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  • Implementing arrays using a stack

    - by Zack
    My programming language has no arrays, no lists, no pointers, no eval and no variable variables. All it has: Ordinary variables like you know them from most programming languages: They all have an exact name and a value. One stack. Functions provided are: push (add element to top), pop (remove element from top, get value) and empty (check if stack is empty) My language is turing-complete. (Basic arithmetics, conditional jumps, etc implemented) That means, it must be possible to implement some sort of list or array, right? But I have no idea how... What I want to achieve: Create a function which can retrieve and/or change an element x of the stack. I could easily add this function in the implementation of my language, in the interpreter, but I want to do it in my programming language. "Solution" one (Accessing an element x, counting from the stack top) Create a loop. Pop off the element from the stack top x times. The last element popped of is element number x. I end up with a destroyed stack. Solution two: Do the same as above, but store all popped off values in a second stack. Then you could move all elements back after you are done. But you know what? I don't have a second stack!

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  • What are the primitive Forth operators?

    - by Barry Brown
    I'm interested in implementing a Forth system, just so I can get some experience building a simple VM and runtime. When starting in Forth, one typically learns about the stack and its operators (DROP, DUP, SWAP, etc.) first, so it's natural to think of these as being among the primitive operators. But they're not. Each of them can be broken down into operators that directly manipulate memory and the stack pointers. Later one learns about store (!) and fetch (@) which can be used to implement DUP, SWAP, and so forth (ha!). So what are the primitive operators? Which ones must be implemented directly in the runtime environment from which all others can be built? I'm not interested in high-performance; I want something that I (and others) can learn from. Operator optimization can come later. (Yes, I'm aware that I can start with a Turing machine and go from there. That's a bit extreme.) Edit: What I'm aiming for is akin to bootstrapping an operating system or a new compiler. What do I need do implement, at minimum, so that I can construct the rest of the system out of those primitive building blocks? I won't implement this on bare hardware; as an educational exercise, I'd write my own minimal VM.

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  • How do people know so much about programming?

    - by Luciano
    I see people in this forums with a lot of points, so I assume they know about a lot of different programming stuff. When I was young I knew about basic (commodore) and the turbo pascal (pc). Then in college I learnt about C, memory management, x86 set, loop invariants, graphs, db query optimization, oop, functional, lambda calculus, prolog, concurrency, polymorphism, newton method, simplex, backtracking, dynamic programming, heuristics, np completeness, LR, LALR, neural networks, static & dynamic typing, turing, godel, and more in between. Then in industry I started with Java several years ago and learnt about it, and its variety of frameworks, and also design patterns, architecture patterns, web development, server development, mobile development, tdd, bdd, uml, use cases, bug trackers, process management, people management if you are a tech lead, profiling, security concerns, etc. I started to forget what I learnt in college... And then there is the stuff I don't know yet, like python, .net, perl, JVM stuff like groovy or scala.. Of course Google is a must for rapid documentation access to know if a problem has been solved already and how, and to keep informed about new stuff by blogs and places like this one. It's just too much or I just have a bad memory.. how do you guys manage it?

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  • Theory of formal languages - Automaton

    - by dader51
    Hi everybody ! I'm wondering about formal languages. I have a kind of parser : It reads à xml-like serialized tree structure and turn it into a multidimmensionnal array. I figured out that i need at least three variables to achieve the job : $tree = array(); // a new array $pTree = array(&$tree); // a new array which the first element points to $tree; $deep = 0; plus the one containing the sentence splitted into words. My point is on the similarities between the algorithm deing used and the differents kinds of automatons ( state machines turing machines stack ... ). The $words variable is the "tape" of the automaton, the test/conditions of the algorithm are transitions, $deep is the state and $tree is the output. I cannont figure what is $pTree. So the question is : which is the automaton I implictly use here, and to which formal languages family does it fit ? And what's about recursion ?

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  • Windows Update and IE fail to connect, but Chrome fine?

    - by I Gottlieb
    Out of ideas on this one. (Running Windows Vista.) I have a program that accesses the internet to retrieve financial market data. One day it tells me that it can't log in -- timeout error. I check the documentation and it says must have a working copy of IE browser installed. I check IE (have IE9) and sure enough -- it just spins. No error message, not timeout, no 'try later' -- just spins -- as far as I can tell, indefinitely. Any page, any address. Even access to a localhost site just spins. Chrome works fine. So does another program I have that fetches market data. Windows 'diagnose and repair' says my internet connection is working fine. I tried uninstall/re-install of IE. Same spinning. I tried to install Windows Updates, and guess what? I can't. I comes up with error 80072efd; checked documentation for the error and it says I should check firewall blockage. Thing is, the only firewall I have is Windows Firewall, and obviously it wouldn't be blocking Windows Update. In contrast, Windows 'Help' in all programs has no problem accessing the Internet. I had a filter on the internet connection, and this was updated just prior to first appearance of the problem. But I uninstalled the filter entirely (official, with passwd from the company's service rep) -- and no difference. I'm guessing that a high level Windows network service file is corrupted -- used only by MS programs and their ilk, but how do I find it? I'd like to avoid having to do a clean install of Windows. Much obliged for any insight. IG Ramhound -- Thanks for reply. I'm familiar with virtual machines as in e.g. JVM or an emulator for an alternative architecture or (theoretical) Turing Machine equivalence. But I'm not familiar with the way you're using the term. Please clarify -- what one needs for this VM 'test' and why you expect it will provide an advantage of insight into the problem. And what sort of 'configuration issue' are you referring to? IG

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  • An Alphabet of Eponymous Aphorisms, Programming Paradigms, Software Sayings, Annoying Alliteration

    - by Brian Schroer
    Malcolm Anderson blogged about “Einstein’s Razor” yesterday, which reminded me of my favorite software development “law”, the name of which I can never remember. It took much Wikipedia-ing to find it (Hofstadter’s Law – see below), but along the way I compiled the following list: Amara’s Law: We tend to overestimate the effect of a technology in the short run and underestimate the effect in the long run. Brook’s Law: Adding manpower to a late software project makes it later. Clarke’s Third Law: Any sufficiently advanced technology is indistinguishable from magic. Law of Demeter: Each unit should only talk to its friends; don't talk to strangers. Einstein’s Razor: “Make things as simple as possible, but not simpler” is the popular paraphrase, but what he actually said was “It can scarcely be denied that the supreme goal of all theory is to make the irreducible basic elements as simple and as few as possible without having to surrender the adequate representation of a single datum of experience”, an overly complicated quote which is an obvious violation of Einstein’s Razor. (You can tell by looking at a picture of Einstein that the dude was hardly an expert on razors or other grooming apparati.) Finagle's Law of Dynamic Negatives: Anything that can go wrong, will—at the worst possible moment. - O'Toole's Corollary: The perversity of the Universe tends towards a maximum. Greenspun's Tenth Rule: Any sufficiently complicated C or Fortran program contains an ad hoc, informally-specified, bug-ridden, slow implementation of half of Common Lisp. (Morris’s Corollary: “…including Common Lisp”) Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law. Issawi’s Omelet Analogy: One cannot make an omelet without breaking eggs - but it is amazing how many eggs one can break without making a decent omelet. Jackson’s Rules of Optimization: Rule 1: Don't do it. Rule 2 (for experts only): Don't do it yet. Kaner’s Caveat: A program which perfectly meets a lousy specification is a lousy program. Liskov Substitution Principle (paraphrased): Functions that use pointers or references to base classes must be able to use objects of derived classes without knowing it Mason’s Maxim: Since human beings themselves are not fully debugged yet, there will be bugs in your code no matter what you do. Nils-Peter Nelson’s Nil I/O Rule: The fastest I/O is no I/O.    Occam's Razor: The simplest explanation is usually the correct one. Parkinson’s Law: Work expands so as to fill the time available for its completion. Quentin Tarantino’s Pie Principle: “…you want to go home have a drink and go and eat pie and talk about it.” (OK, he was talking about movies, not software, but I couldn’t find a “Q” quote about software. And wouldn’t it be cool to write a program so great that the users want to eat pie and talk about it?) Raymond’s Rule: Computer science education cannot make anybody an expert programmer any more than studying brushes and pigment can make somebody an expert painter.  Sowa's Law of Standards: Whenever a major organization develops a new system as an official standard for X, the primary result is the widespread adoption of some simpler system as a de facto standard for X. Turing’s Tenet: We shall do a much better programming job, provided we approach the task with a full appreciation of its tremendous difficulty, provided that we respect the intrinsic limitations of the human mind and approach the task as very humble programmers.  Udi Dahan’s Race Condition Rule: If you think you have a race condition, you don’t understand the domain well enough. These rules didn’t exist in the age of paper, there is no reason for them to exist in the age of computers. When you have race conditions, go back to the business and find out actual rules. Van Vleck’s Kvetching: We know about as much about software quality problems as they knew about the Black Plague in the 1600s. We've seen the victims' agonies and helped burn the corpses. We don't know what causes it; we don't really know if there is only one disease. We just suffer -- and keep pouring our sewage into our water supply. Wheeler’s Law: All problems in computer science can be solved by another level of indirection... Except for the problem of too many layers of indirection. Wheeler also said “Compatibility means deliberately repeating other people's mistakes.”. The Wrong Road Rule of Mr. X (anonymous): No matter how far down the wrong road you've gone, turn back. Yourdon’s Rule of Two Feet: If you think your management doesn't know what it's doing or that your organisation turns out low-quality software crap that embarrasses you, then leave. Zawinski's Law of Software Envelopment: Every program attempts to expand until it can read mail. Zawinski is also responsible for “Some people, when confronted with a problem, think 'I know, I'll use regular expressions.' Now they have two problems.” He once commented about X Windows widget toolkits: “Using these toolkits is like trying to make a bookshelf out of mashed potatoes.”

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  • College Courses through distance learning

    - by Matt
    I realize this isn't really a programming question, but didn't really know where to post this in the stackexchange and because I am a computer science major i thought id ask here. This is pretty unique to the programmer community since my degree is about 95% programming. I have 1 semester left, but i work full time. I would like to finish up in December, but to make things easier i like to take online classes whenever I can. So, my question is does anyone know of any colleges that offer distance learning courses for computer science? I have been searching around and found a few potential classes, but not sure yet. I would like to gather some classes and see what i can get approval for. Class I need: Only need one C SC 437 Geometric Algorithms C SC 445 Algorithms C SC 473 Automata Only need one C SC 452 Operating Systems C SC 453 Compilers/Systems Software While i only need of each of the above courses i still need to take two more electives. These also have to be upper 400 level classes. So i can take multiple in each category. Some other classes I can take are: CSC 447 - Green Computing CSC 425 - Computer Networking CSC 460 - Database Design CSC 466 - Computer Security I hoping to take one or two of these courses over the summer. If not, then online over the regular semester would be ok too. Any help in helping find these classes would be awesome. Maybe you went to a college that offered distance learning. Some of these classes may be considered to be graduate courses too. Descriptions are listed below if you need. Thanks! Descriptions Computer Security This is an introductory course covering the fundamentals of computer security. In particular, the course will cover basic concepts of computer security such as threat models and security policies, and will show how these concepts apply to specific areas such as communication security, software security, operating systems security, network security, web security, and hardware-based security. Computer Networking Theory and practice of computer networks, emphasizing the principles underlying the design of network software and the role of the communications system in distributed computing. Topics include routing, flow and congestion control, end-to-end protocols, and multicast. Database Design Functions of a database system. Data modeling and logical database design. Query languages and query optimization. Efficient data storage and access. Database access through standalone and web applications. Green Computing This course covers fundamental principles of energy management faced by designers of hardware, operating systems, and data centers. We will explore basic energy management option in individual components such as CPUs, network interfaces, hard drives, memory. We will further present the energy management policies at the operating system level that consider performance vs. energy saving tradeoffs. Finally we will consider large scale data centers where energy management is done at multiple layers from individual components in the system to shutting down entries subset of machines. We will also discuss energy generation and delivery and well as cooling issues in large data centers. Compilers/Systems Software Basic concepts of compilation and related systems software. Topics include lexical analysis, parsing, semantic analysis, code generation; assemblers, loaders, linkers; debuggers. Operating Systems Concepts of modern operating systems; concurrent processes; process synchronization and communication; resource allocation; kernels; deadlock; memory management; file systems. Algorithms Introduction to the design and analysis of algorithms: basic analysis techniques (asymptotics, sums, recurrences); basic design techniques (divide and conquer, dynamic programming, greedy, amortization); acquiring an algorithm repertoire (sorting, median finding, strong components, spanning trees, shortest paths, maximum flow, string matching); and handling intractability (approximation algorithms, branch and bound). Automata Introduction to models of computation (finite automata, pushdown automata, Turing machines), representations of languages (regular expressions, context-free grammars), and the basic hierarchy of languages (regular, context-free, decidable, and undecidable languages). Geometric Algorithms The study of algorithms for geometric objects, using a computational geometry approach, with an emphasis on applications for graphics, VLSI, GIS, robotics, and sensor networks. Topics may include the representation and overlaying of maps, finding nearest neighbors, solving linear programming problems, and searching geometric databases.

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  • Subroutine & GoTo design

    - by sub
    I have a strange question concerning subroutines: As I'm creating a minimal language and I don't want to add high-level loops like while or for I was planning on just adding gotos to keep it Turing-Complete. Now I thought, eww - gotos - I wouldn't want to program in that language if I had to use gotos so often. So I thought about adding subroutines instead. I see the difference as the following: gotos Go to (captain obvious) a previously defined point and continue executing the program from there. Leads to hardly understandable and buggy code, I think that's a fact. subroutines Similiar: You define their starting point somewhere, as you call them the program jumps there - but the subroutine can go back to the point it was called from with return. Okay. Why didn't I just add the more function-like, nice looking subroutines? Because: In order to make return work if I call subroutines from within subroutines from within other subroutines, I'd have to use a stack containing the point where the currently running subroutine came from at top. That would then mean that I would, if I create loops using the subroutines, end up with an extremely memory-eating, overflowing stack with return locations. Not good. Don't think of my subroutines as functions. They are just gotos that return to the point they were called from, they don't actually give back values like the return x; statement in nearly all today's languages. Now to my actual questions: How can I solve the above problem with the stack overflow on loops with subroutines? Do I have to add a separate goto language construct without the return option? Assembler doesn't have loops but as I have seen myJumpPoint:, jnz, jz, retn. That means to me that there must also be a stack containing all the return locations. Am I right with that? What about long running loops then? Don't they overflow the stack/eat memory then? Am I getting the retn symbol in assembler totally wrong? If yes, please explain it to me.

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  • How hard programming is? Really. [closed]

    - by Bubba88
    Hi! The question is about your perception of programming activity. How hard/exacting this task is? There is much buzz about programming nowadays, people say that programmers are smart, very technical and abstract at a time, know much about world, psychology etc.. They say, that programmers got really powerful brain thing, cause there is much to keep in consideration simultaneously again with much information folded into each other associatively (up 10 levels of folding they say))) Still, there are some terms to specify at our own.. So that is the question: What do you think about programming in general? Is it hard? Is it 'for everyone' or for the particular kind of people only? How much non-CS background do you need to program (just to program, really; enterprise applications for example)? How long is the learning curve? (again, for programming in general) And another bunch of random questions: - If you were not to like/love programming, would that be a serious trouble bothering your current employment? - If you were to start from the beginning, would you chose that direction this time? - What other areas (jobs or maybe hobbies) are comparable to programming in the way they can explode someone's lovely brain? - Is 'non turing-complete programming' (SQL, XML, etc.) comparable to what we do or is it really way easier, less requiring, cheap and akin to cooking :)? Well, the essence is: How would you describe programming activity WRT to its difficulty? Or, on the other hand: Did you ever catch yourself thinking at some point: OMG, it's sooo hard! I don't know how would I ever program, even carried away this way and doing programming just for fun? It's very interesting to know your opinion, your'e the programmers after all. I mean much people must be exaggerating/speculating about the thing they do not really know about. But that musn't be the case here on SO :) P.S.: I'll try my best to update this post later, and you please edit it too. At least I'll get decent English in my question text :)

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  • Connect to SQLite Database using Eclipse (Java)

    - by bnabilos
    Hello, I'm trying to connect to SQLite database with Ecplise but I have some errors. This is my Java code and the errors that I get on output. Please see if you can help me. Thank you in advance. package jdb; import java.sql.*; public class Test { public static void main(String[] args) throws Exception { Class.forName("org.sqlite.JDBC"); Connection conn = DriverManager.getConnection("jdbc:sqlite:/Applications/MAMP/db/sqlite/test.sqlite"); Statement stat = conn.createStatement(); stat.executeUpdate("drop table if exists people;"); stat.executeUpdate("create table people (name, occupation);"); PreparedStatement prep = conn.prepareStatement( "insert into people values (?, ?);"); prep.setString(1, "Gandhi"); prep.setString(2, "politics"); prep.addBatch(); prep.setString(1, "Turing"); prep.setString(2, "computers"); prep.addBatch(); prep.setString(1, "Wittgenstein"); prep.setString(2, "smartypants"); prep.addBatch(); conn.setAutoCommit(false); prep.executeBatch(); conn.setAutoCommit(true); ResultSet rs = stat.executeQuery("select * from people;"); while (rs.next()) { System.out.println("name = " + rs.getString("name")); System.out.println("job = " + rs.getString("occupation")); } rs.close(); conn.close(); } } ans that what I get in Ecplise : Exception in thread "main" java.lang.ClassNotFoundException: org.sqlite.JDBC at java.net.URLClassLoader$1.run(URLClassLoader.java:200) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:188) at java.lang.ClassLoader.loadClass(ClassLoader.java:315) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:330) at java.lang.ClassLoader.loadClass(ClassLoader.java:250) at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:398) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:169) at jdb.Test.main(Test.java:7) Thank you

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  • How does this main domain have a CNAME record?

    - by TRiG
    I was under the impression that only subdomains could have CNAME records: main domains need to define all their own records. However, apt-get.com seems to have only a CNAME record. How can this work? $ dig apt-get.com ; <<>> DiG 9.8.1-P1 <<>> apt-get.com ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 45743 ;; flags: qr rd ra; QUERY: 1, ANSWER: 9, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;apt-get.com. IN A ;; ANSWER SECTION: apt-get.com. 86336 IN CNAME thie5ku9.dsgeneration.com. thie5ku9.dsgeneration.com. 60 IN A 208.73.211.242 thie5ku9.dsgeneration.com. 60 IN A 208.73.211.246 thie5ku9.dsgeneration.com. 60 IN A 208.73.211.166 thie5ku9.dsgeneration.com. 60 IN A 208.73.211.232 thie5ku9.dsgeneration.com. 60 IN A 208.73.211.161 thie5ku9.dsgeneration.com. 60 IN A 208.73.210.233 thie5ku9.dsgeneration.com. 60 IN A 208.73.211.186 thie5ku9.dsgeneration.com. 60 IN A 208.73.211.188 ;; Query time: 59 msec ;; SERVER: 127.0.0.1#53(127.0.0.1) ;; WHEN: Tue Jun 10 15:05:48 2014 ;; MSG SIZE rcvd: 193 $ dig apt-get.com ns ; <<>> DiG 9.8.1-P1 <<>> apt-get.com ns ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 43831 ;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0 ;; QUESTION SECTION: ;apt-get.com. IN NS ;; Query time: 26 msec ;; SERVER: 127.0.0.1#53(127.0.0.1) ;; WHEN: Tue Jun 10 15:12:37 2014 ;; MSG SIZE rcvd: 29 $ dig apt-get.com ns @b.gtld-servers.net ; <<>> DiG 9.8.1-P1 <<>> apt-get.com ns @b.gtld-servers.net ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 38228 ;; flags: qr rd; QUERY: 1, ANSWER: 0, AUTHORITY: 2, ADDITIONAL: 2 ;; WARNING: recursion requested but not available ;; QUESTION SECTION: ;apt-get.com. IN NS ;; AUTHORITY SECTION: apt-get.com. 172800 IN NS ns1.domainrecover.com. apt-get.com. 172800 IN NS ns2.domainrecover.com. ;; ADDITIONAL SECTION: ns1.domainrecover.com. 172800 IN A 66.45.232.66 ns2.domainrecover.com. 172800 IN A 65.23.159.179 ;; Query time: 70 msec ;; SERVER: 192.33.14.30#53(192.33.14.30) ;; WHEN: Tue Jun 10 15:07:05 2014 ;; MSG SIZE rcvd: 111 The domain does resolve. I get the following headers: GET / HTTP/1.1 User-Agent: Testing_Sniffer/4.15 Host: apt-get.com Accept: */* HTTP/1.0 200 (OK) Cache-Control: private, no-cache, must-revalidate Connection: Keep-Alive Pragma: no-cache Server: Oversee Turing v1.0.0 Content-Length: 1347 Content-Type: text/html Expires: Mon, 26 Jul 1997 05:00:00 GMT Keep-Alive: timeout=3, max=96 P3P: policyref="http://www.dsparking.com/w3c/p3p.xml", CP="NOI DSP COR ADMa OUR NOR STA" Set-Cookie: parkinglot=1; domain=.apt-get.com; path=/; expires=Wed, 11-Jun-2014 14:10:37 GMT <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Frameset//EN" "http://www.w3.org/TR/html4/frameset.dtd"> <!-- turing_cluster_prod --> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>apt-get.com</title> <meta name="keywords" content="apt-get.com" /> <meta name="description" content="apt-get.com" /> <meta name="robots" content="index, follow" /> <meta name="revisit-after" content="10" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <script type="text/javascript"> document.cookie = "jsc=1"; </script> </head> <frameset rows="100%,*" frameborder="no" border="0" framespacing="0"> <frame src="http://apt-get.com?epl=5PfLSSqWrYDAt-gbwMDK_rA3b1UJCYVTJHfxTzr9FTDQV84b6vAgVhU3FTeCRQNiuRNv79Ni0V3mkEVNRhpqo2gpMjp5iOIR1w2_EISPENaqzoXohVXl2QI3ryXlRCB4FaIIaxynnWXWY6QBgBgNiIZ6agD1NBoNGg0ajXpUCXUAIJDer78AAOB_AwAAQIDbCwAAe_NWlVlTJllBMTZoWkKPAAAA8A" name="apt-get.com"> </frameset> <noframes> <body><a href="http://apt-get.com?epl=5PfLSSqWrYDAt-gbwMDK_rA3b1UJCYVTJHfxTzr9FTDQV84b6vAgVhU3FTeCRQNiuRNv79Ni0V3mkEVNRhpqo2gpMjp5iOIR1w2_EISPENaqzoXohVXl2QI3ryXlRCB4FaIIaxynnWXWY6QBgBgNiIZ6agD1NBoNGg0ajXpUCXUAIJDer78AAOB_AwAAQIDbCwAAe_NWlVlTJllBMTZoWkKPAAAA8A">Click here to go to apt-get.com</a>.</body> </noframes> </html>

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  • CodePlex Daily Summary for Sunday, October 30, 2011

    CodePlex Daily Summary for Sunday, October 30, 2011Popular ReleasesKoober: Koober - The Ebook Creator 0.2: The official release of Koober as Open source. Koober is a ebook creator for Windows, and Koob Reader is the reader.?????????????: ??????????????: ??????????????VidCoder: 1.2.0: Updated to HandBrake svn 4311. Refactored to read in list of encoders from HandBrake itself. Added ffaac, FLAC audio and ffmpeg2 video. Reworked audio encoding UI: removed grid and gave each encoding more vertical space. Added audio quality targeting and compression. Added status messages. Added messages for a few events (encode start/stop, playing a preview clip, update available, update download finished). Made source and destination path UI elements smarter about what parts they cut ...patterns & practices: Enterprise Library Contrib: Enterprise Library Contrib - 5.0 (Oct 2011): This release of Enterprise Library Contrib is based on the Microsoft patterns & practices Enterprise Library 5.0 core and contains the following: Common extensionsTypeConfigurationElement<T> - A Polymorphic Configuration Element without having to be part of a PolymorphicConfigurationElementCollection. AnonymousConfigurationElement - A Configuration element that can be uniquely identified without having to define its name explicitly. Data Access Application Block extensionsMySql Provider - ...Network Monitor Open Source Parsers: Network Monitor Parsers 3.4.2748: The Network Monitor Parsers packages contain parsers for more than 400 network protocols, including RFC based public protocols and protocols for Microsoft products defined in the Microsoft Open Specifications for Windows and SQL Server. NetworkMonitor_Parsers.msi is the base parser package which defines parsers for commonly used public protocols and protocols for Microsoft Windows. In this release, NetowrkMonitor_Parsers.msi continues to improve quality and fix bugs. It has included the fo...Duckworth Lewis Professional Edition Calculator: DLcalc 3.0: DLcalc 3.0 can perform Duckworth/Lewis Professional Edition calculations 100% accurately. It also produces over-by-over and ball-by-ball PAR score tables.Folder Bookmarks: Folder Bookmarks 2.2.0.1: In this version: Custom Icons - now you can change the icons of the bookmarks. By default, whenever an image is added, the icon is automatically changed to a thumbnail of the picture. This can be turned off in the settings (Options... > Settings) Ability to remove items from the 'Recent' category Bugfixes - 'Choose' button in 'Edit Bookmark' now works Another bug fix: another problem in the 'Edit Bookmark' windowMedia Companion: MC 3.420b Weekly: Ensure .NET 4.0 Full Framework is installed. (Available from http://www.microsoft.com/download/en/details.aspx?id=17718) Ensure the NFO ID fix is applied when transitioning from versions prior to 3.416b. (Details here) Movies Fixed: Fanart and poster scraping issues TV Shows (Re)Added: Rebuild single show Fixed: Issue when shows are moved from original location Ability to handle " for actor nicknames Crash when episode name contains "<" (does not scrape yet) Clears fanart when switch...patterns & practices - Unity: Unity 3.0 for .NET4.5 Preview: The Unity 3.0.1026.0 Preview enables Unity to work on .NET 4.5 with both the WinRT and desktop profiles. The major changes include: Unity projects updated to target .NET 4.5. Dynamic build plans modified to use compiled lambda expressions instead of Reflection.Emit Converting reflection to use the new TypeInfo for reflection. Projects updated to work with the Microsoft Visual Studio 2011 Preview Notes/Known Issues: The Microsoft.Practices.Unity.UnityServiceLocator class cannot be use...Managed Extensibility Framework: MEF 2 Preview 4: Detailed information on this release is available on the BCL team blog.Image Converter: Image Converter 0.3: New Features: - English and German support Technical Improvements: - Microsoft All Rules using Code Analysis Planned Features for future release: 1. Unit testing 2. Command line interface 3. Automatic UpdatesAcDown????? - Anime&Comic Downloader: AcDown????? v3.6: ?? ● AcDown??????????、??????,??????????????????????,???????Acfun、Bilibili、???、???、???、Tucao.cc、SF???、?????80????,???????????、?????????。 ● AcDown???????????????????????????,???,???????????????????。 ● AcDown???????C#??,????.NET Framework 2.0??。?????"Acfun?????"。 ????32??64? Windows XP/Vista/7 ????????????? ??:????????Windows XP???,?????????.NET Framework 2.0???(x86)?.NET Framework 2.0???(x64),?????"?????????"??? ??????????????,??????????: ??"AcDown?????"????????? ?? v3.6?? ??“????”...Path Copy Copy: 8.0: New version that mostly adds lots of requested features: 11340 11339 11338 11337 This version also features a more elaborate Settings UI that has several tabs. I tried to add some notes to better explain the use and purpose of the various options. The Path Copy Copy documentation is also on the way, both to explain how to develop custom plugins and to explain how to pre-configure options if you're a network admin. Stay tuned.MVC Controls Toolkit: Mvc Controls Toolkit 1.5.0: Added: The new Client Blocks feaure of Views A new "move" js method for the TreeViews The NewHtmlCreated js event to the DataGrid Improved the ChoiceList structure that now allows also the selection list of a dropdown to be chosen with a lambda expression Improved the AcceptViewHintAttribute controller filter. Now a client can specify not only the name of a View or Partial View it prefers, but also to receive just the rough data in Json format. Now the the SMinimum and SMaximum par...Free SharePoint Master Pages: Buried Alive (Halloween) Theme: Release Notes *Created for Halloween, you will find theme file, custom css file and images. *Created by Al Roome @AlstarRoome Features: Custom styling for web part Custom background *Screenshot https://s3.amazonaws.com/kkhipple/post/sharepoint-showcase-halloween.pngDevForce Application Framework: DevForce AF 2.0.3 RTW: PrerequisitesWPF 4.0 Silverlight 4.0 DevForce 2010 6.1.3.1 Download ContentsDebug and Release Assemblies API Documentation Source code License.txt Requirements.txt Release HighlightsNew: EventAggregator event forwarding New: EntityManagerInterceptor<T> to intercept EntityManger events New: IHarnessAware to allow for ViewModel setup when executed inside of the Development Harness New: Improved design time stability New: Support for add-in development New: CoroutineFns.To...NicAudio: NicAudio 2.0.5: Minor change to accept special DTS stereo modes (LtRt, AB,...)NDepend TFS 2010 integration: version 0.5.0 beta 1: Only the activity and the VS plugin are avalaible right now. They basically work. Data types that are logged into tfs reports are subject to change. This is no big deal since data is not yet sent into the warehouse.Windows Azure Toolkit for Windows Phone: Windows Azure Toolkit for Windows Phone v1.3.1: Upgraded Windows Azure projects to Windows Azure Tools for Microsoft Visual Studio 2010 1.5 – September 2011 Upgraded the tools tools to support the Windows Phone Developer Tools RTW Update SQL Azure only scenarios to use ASP.NET Universal Providers (through the System.Web.Providers v1.0.1 NuGet package) Changed Shared Access Signature service interface to support more operations Refactored Blobs API to have a similar interface and usage to that provided by the Windows Azure SDK Stor...DotNetNuke® FAQ: 05.00.00: FAQ (Frequently Asked Questions) 05.00.00 will work for any DNN version 5.6.1 and up. It is the first version which is rewritten in C#. The scope of this update is to fix all known issues and improve user interface. Please review and rate this release... (stars are welcome)BUG FIXESManage Categories button text was not localized Edit/Add FAQ Entry: button text was not localized ENHANCEMENTSAdded an option to select the control for category display: Listbox with checkboxes (flat category ...New ProjectsalphaCards: Digitale LernkarteiBinary Code Interpreter: The Binary Code Interpreter is a small and funny programming languaage. This interpreter works a bit like a Turing Machine.Buscar ciudades: This is the source code for the application "Buscar ciudades" published in the Windows Phone Marketplace. CamOnWeb - Componente para WebCam: Este projeto tem como objetivo o desenvolvimento um componente para captura e exibição de videos da webcam. Compare.Net: Compare.Net is a configurable application to compare and reconclie from different sources. C# WPF applcation targeting .Net 4CSGame: Academic project for our studies. Subject "Client -server technology"curbside: curbsideDanish Language Pack for Community Server: Danish Language Packs for Community Server 2.1 and 2007. At its inception, this project contains quite incomplete translations to Danish. This project provides a common resource where all interested parties can gradually improve on this language pack. Please join to improve the contents. The source code tree contains two major folders: One for Community Server 2.1 and one for Community Server 2007.Dependency Variable Lib: ??????????????????、?????????????????????。(???????、?????????????w) ???、「??×??=??」???????????????、????????、????????、???「??×??」????????????????????????????????????。 FreedBack: FreedBack allows you to quickly and easily embed a configurable feedback form into any web application. It can be a standalone application that you install and deploy, then embed a bit of script into existing apps to implement feedback, or you can make it part of your MVC App.Hageveld - NieuwsModule (Chris' Tutorial: A news article manager made for educational purposes.Idea Resto: Aplicación para restaurantes.jqgridmvcgeneration: codesmith template that creates js, html and asp.net mvc server side json server for a jqgrid -based table on a arbitratrary database table. The code includes pagination and server side sorting. Jqgrid is a great jquery extension that provides an ajax-enabled fully customizable interactive table based on server side data. However, the actual coding can be a bit tedious and cryptic. This project provides a template base approach that basically performs two tasks: 1. creates a client si...MyClassMapper: A simple configurable classmapper for mapping ClassA to ClassB and vice versa, the ideas are borrowed from the Dozer project (http://dozer.sourceforge.net). Most code is based on 'Dynamic Access' code from Hongju Cao <hjcao_wei@hotmail.com> (All that code is located in the "DynamicAccess" sub-directory from the project.)NavigateTo Providers: This project is a collection of NavigateTo providers for Visual Studio 2010. NObsidian: A proxy component to access Obisidian Portal API from .NetNSession: The objective of this project is to allow ASP Classic to access ASP.NET out-of-process session stores in the same way that ASP.NET accesses them, and thus share the session state with ASP.NET.NTextile: NTextile is a lightweight, humane web compatible markup generator. It generates valid XHTML output using simple easy to remember conventions and text characters (a.k.a modifiers), to markup plain text. NTextile is especially useful to provide quick and valid markup for .NET web applications. For e.g. wikis, blogs, online forums, content management systems etc. This project was inspired by Dean Allen’s original Textile features, as included in the Textpattern content management application. T...OpenTasksBehaviorsLibrary for Windows Phone: Open Tasks Behavior for Windows Phone *OpenWebBrowserTask *OpenMediaLauncherTaskPowerShell Cmdlet Sample: PowerShell Cmdlet SamplePrismEx: PrismEx is a library of helpers and extension methods to allow developers to more easily develop and test Prism applications. QuickDelete: A Windows Explorer add-on to delete files and folders very quickly, much more so than the usual Explorer command. Works on Windows XP or later. Currently in EXPERIMENTAL state. No releases have been produced yet.Quiz Module for DotNetNuke: This is a module that allows you to quickly and easily provide a quiz that can be taken by the visitors on your DotNetNuke website.RaptorDB - The Key Value Store: Smallest, fastest embedded nosql persisted dictionary using b+tree or MurMur hash indexing. (Now with Hybrid WAH bitmap indexes)Rockin CMS-LMS Combo: RockinCmsLms Combo provides a great way for users to build their content and training sites with one great tool. It will be developed with C# 4.0-4.5, Silverlight, JQuery, and ASP.Net and MVC 3.0 with Razor. This project will demonstrate how to use todays technologies to build solutions that last. We may have 2 versions - one with a local db and one with a Windows Azure storage solution. Suggest using the Web Platform Installer to get all of the components.SandKeeper - Time Tracking Addin for Outlook 2010 tasks: SandKeeper is an Outlook Addin that enables you to track time for your tasks.Share: Share is a new web-based content management system. For more information about this project, please visit http://blog.aphysoft.com.SharePoint 2010 ViewEdit Group By Content Type: A simple project that injects JavaScript into the ribbon bar area to add "Content Type" as a choice on the ViewEdit.aspx page. With this, users can once again create views that group by Content Type without having to use SharePoint Designer 2010.Simple Merge Sort: This is a simple implementation of Merge-Sort, using to sort an Array of Integers.UKag: Unity3D?Kr2/KAG3??moduleUsingLinq: TestUtec Logger: Utec Logger is meant to be used the Turbo XS UTEC and UTEC Delta. It is simply a data logger application, it will auto logged based on pre defined conditionals. It also takes this information and displays it in a two dimensional table, averaging the values appropriately to ease of log analysis.WOXalizer: Fork of WOX project. http://woxserializer.sourceforge.net/Zeta Backup Validator: A small .NET 3.5 console application that helps you verifying whether your backups succeed by checking files and folders with various configurable rules (folder size, file age, etc.).Zeta Links: A web application for generating and measuring shortcut hyperlinks, similar to bit.ly.Zombie Slayer v1.0: Zombie Slayer v1.0 is an action first person shooter where players can try and survive a never-ending wave of zombies for as long as they can while a timer keeps track of how long they survived and posts times online from longest to shortest.?????????????: ??????????????????,????。

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  • Toorcon14

    - by danx
    Toorcon 2012 Information Security Conference San Diego, CA, http://www.toorcon.org/ Dan Anderson, October 2012 It's almost Halloween, and we all know what that means—yes, of course, it's time for another Toorcon Conference! Toorcon is an annual conference for people interested in computer security. This includes the whole range of hackers, computer hobbyists, professionals, security consultants, press, law enforcement, prosecutors, FBI, etc. We're at Toorcon 14—see earlier blogs for some of the previous Toorcon's I've attended (back to 2003). This year's "con" was held at the Westin on Broadway in downtown San Diego, California. The following are not necessarily my views—I'm just the messenger—although I could have misquoted or misparaphrased the speakers. Also, I only reviewed some of the talks, below, which I attended and interested me. MalAndroid—the Crux of Android Infections, Aditya K. Sood Programming Weird Machines with ELF Metadata, Rebecca "bx" Shapiro Privacy at the Handset: New FCC Rules?, Valkyrie Hacking Measured Boot and UEFI, Dan Griffin You Can't Buy Security: Building the Open Source InfoSec Program, Boris Sverdlik What Journalists Want: The Investigative Reporters' Perspective on Hacking, Dave Maas & Jason Leopold Accessibility and Security, Anna Shubina Stop Patching, for Stronger PCI Compliance, Adam Brand McAfee Secure & Trustmarks — a Hacker's Best Friend, Jay James & Shane MacDougall MalAndroid—the Crux of Android Infections Aditya K. Sood, IOActive, Michigan State PhD candidate Aditya talked about Android smartphone malware. There's a lot of old Android software out there—over 50% Gingerbread (2.3.x)—and most have unpatched vulnerabilities. Of 9 Android vulnerabilities, 8 have known exploits (such as the old Gingerbread Global Object Table exploit). Android protection includes sandboxing, security scanner, app permissions, and screened Android app market. The Android permission checker has fine-grain resource control, policy enforcement. Android static analysis also includes a static analysis app checker (bouncer), and a vulnerablity checker. What security problems does Android have? User-centric security, which depends on the user to grant permission and make smart decisions. But users don't care or think about malware (the're not aware, not paranoid). All they want is functionality, extensibility, mobility Android had no "proper" encryption before Android 3.0 No built-in protection against social engineering and web tricks Alternative Android app markets are unsafe. Simply visiting some markets can infect Android Aditya classified Android Malware types as: Type A—Apps. These interact with the Android app framework. For example, a fake Netflix app. Or Android Gold Dream (game), which uploads user files stealthy manner to a remote location. Type K—Kernel. Exploits underlying Linux libraries or kernel Type H—Hybrid. These use multiple layers (app framework, libraries, kernel). These are most commonly used by Android botnets, which are popular with Chinese botnet authors What are the threats from Android malware? These incude leak info (contacts), banking fraud, corporate network attacks, malware advertising, malware "Hackivism" (the promotion of social causes. For example, promiting specific leaders of the Tunisian or Iranian revolutions. Android malware is frequently "masquerated". That is, repackaged inside a legit app with malware. To avoid detection, the hidden malware is not unwrapped until runtime. The malware payload can be hidden in, for example, PNG files. Less common are Android bootkits—there's not many around. What they do is hijack the Android init framework—alteering system programs and daemons, then deletes itself. For example, the DKF Bootkit (China). Android App Problems: no code signing! all self-signed native code execution permission sandbox — all or none alternate market places no robust Android malware detection at network level delayed patch process Programming Weird Machines with ELF Metadata Rebecca "bx" Shapiro, Dartmouth College, NH https://github.com/bx/elf-bf-tools @bxsays on twitter Definitions. "ELF" is an executable file format used in linking and loading executables (on UNIX/Linux-class machines). "Weird machine" uses undocumented computation sources (I think of them as unintended virtual machines). Some examples of "weird machines" are those that: return to weird location, does SQL injection, corrupts the heap. Bx then talked about using ELF metadata as (an uintended) "weird machine". Some ELF background: A compiler takes source code and generates a ELF object file (hello.o). A static linker makes an ELF executable from the object file. A runtime linker and loader takes ELF executable and loads and relocates it in memory. The ELF file has symbols to relocate functions and variables. ELF has two relocation tables—one at link time and another one at loading time: .rela.dyn (link time) and .dynsym (dynamic table). GOT: Global Offset Table of addresses for dynamically-linked functions. PLT: Procedure Linkage Tables—works with GOT. The memory layout of a process (not the ELF file) is, in order: program (+ heap), dynamic libraries, libc, ld.so, stack (which includes the dynamic table loaded into memory) For ELF, the "weird machine" is found and exploited in the loader. ELF can be crafted for executing viruses, by tricking runtime into executing interpreted "code" in the ELF symbol table. One can inject parasitic "code" without modifying the actual ELF code portions. Think of the ELF symbol table as an "assembly language" interpreter. It has these elements: instructions: Add, move, jump if not 0 (jnz) Think of symbol table entries as "registers" symbol table value is "contents" immediate values are constants direct values are addresses (e.g., 0xdeadbeef) move instruction: is a relocation table entry add instruction: relocation table "addend" entry jnz instruction: takes multiple relocation table entries The ELF weird machine exploits the loader by relocating relocation table entries. The loader will go on forever until told to stop. It stores state on stack at "end" and uses IFUNC table entries (containing function pointer address). The ELF weird machine, called "Brainfu*k" (BF) has: 8 instructions: pointer inc, dec, inc indirect, dec indirect, jump forward, jump backward, print. Three registers - 3 registers Bx showed example BF source code that implemented a Turing machine printing "hello, world". More interesting was the next demo, where bx modified ping. Ping runs suid as root, but quickly drops privilege. BF modified the loader to disable the library function call dropping privilege, so it remained as root. Then BF modified the ping -t argument to execute the -t filename as root. It's best to show what this modified ping does with an example: $ whoami bx $ ping localhost -t backdoor.sh # executes backdoor $ whoami root $ The modified code increased from 285948 bytes to 290209 bytes. A BF tool compiles "executable" by modifying the symbol table in an existing ELF executable. The tool modifies .dynsym and .rela.dyn table, but not code or data. Privacy at the Handset: New FCC Rules? "Valkyrie" (Christie Dudley, Santa Clara Law JD candidate) Valkyrie talked about mobile handset privacy. Some background: Senator Franken (also a comedian) became alarmed about CarrierIQ, where the carriers track their customers. Franken asked the FCC to find out what obligations carriers think they have to protect privacy. The carriers' response was that they are doing just fine with self-regulation—no worries! Carriers need to collect data, such as missed calls, to maintain network quality. But carriers also sell data for marketing. Verizon sells customer data and enables this with a narrow privacy policy (only 1 month to opt out, with difficulties). The data sold is not individually identifiable and is aggregated. But Verizon recommends, as an aggregation workaround to "recollate" data to other databases to identify customers indirectly. The FCC has regulated telephone privacy since 1934 and mobile network privacy since 2007. Also, the carriers say mobile phone privacy is a FTC responsibility (not FCC). FTC is trying to improve mobile app privacy, but FTC has no authority over carrier / customer relationships. As a side note, Apple iPhones are unique as carriers have extra control over iPhones they don't have with other smartphones. As a result iPhones may be more regulated. Who are the consumer advocates? Everyone knows EFF, but EPIC (Electrnic Privacy Info Center), although more obsecure, is more relevant. What to do? Carriers must be accountable. Opt-in and opt-out at any time. Carriers need incentive to grant users control for those who want it, by holding them liable and responsible for breeches on their clock. Location information should be added current CPNI privacy protection, and require "Pen/trap" judicial order to obtain (and would still be a lower standard than 4th Amendment). Politics are on a pro-privacy swing now, with many senators and the Whitehouse. There will probably be new regulation soon, and enforcement will be a problem, but consumers will still have some benefit. Hacking Measured Boot and UEFI Dan Griffin, JWSecure, Inc., Seattle, @JWSdan Dan talked about hacking measured UEFI boot. First some terms: UEFI is a boot technology that is replacing BIOS (has whitelisting and blacklisting). UEFI protects devices against rootkits. TPM - hardware security device to store hashs and hardware-protected keys "secure boot" can control at firmware level what boot images can boot "measured boot" OS feature that tracks hashes (from BIOS, boot loader, krnel, early drivers). "remote attestation" allows remote validation and control based on policy on a remote attestation server. Microsoft pushing TPM (Windows 8 required), but Google is not. Intel TianoCore is the only open source for UEFI. Dan has Measured Boot Tool at http://mbt.codeplex.com/ with a demo where you can also view TPM data. TPM support already on enterprise-class machines. UEFI Weaknesses. UEFI toolkits are evolving rapidly, but UEFI has weaknesses: assume user is an ally trust TPM implicitly, and attached to computer hibernate file is unprotected (disk encryption protects against this) protection migrating from hardware to firmware delays in patching and whitelist updates will UEFI really be adopted by the mainstream (smartphone hardware support, bank support, apathetic consumer support) You Can't Buy Security: Building the Open Source InfoSec Program Boris Sverdlik, ISDPodcast.com co-host Boris talked about problems typical with current security audits. "IT Security" is an oxymoron—IT exists to enable buiness, uptime, utilization, reporting, but don't care about security—IT has conflict of interest. There's no Magic Bullet ("blinky box"), no one-size-fits-all solution (e.g., Intrusion Detection Systems (IDSs)). Regulations don't make you secure. The cloud is not secure (because of shared data and admin access). Defense and pen testing is not sexy. Auditors are not solution (security not a checklist)—what's needed is experience and adaptability—need soft skills. Step 1: First thing is to Google and learn the company end-to-end before you start. Get to know the management team (not IT team), meet as many people as you can. Don't use arbitrary values such as CISSP scores. Quantitive risk assessment is a myth (e.g. AV*EF-SLE). Learn different Business Units, legal/regulatory obligations, learn the business and where the money is made, verify company is protected from script kiddies (easy), learn sensitive information (IP, internal use only), and start with low-hanging fruit (customer service reps and social engineering). Step 2: Policies. Keep policies short and relevant. Generic SANS "security" boilerplate policies don't make sense and are not followed. Focus on acceptable use, data usage, communications, physical security. Step 3: Implementation: keep it simple stupid. Open source, although useful, is not free (implementation cost). Access controls with authentication & authorization for local and remote access. MS Windows has it, otherwise use OpenLDAP, OpenIAM, etc. Application security Everyone tries to reinvent the wheel—use existing static analysis tools. Review high-risk apps and major revisions. Don't run different risk level apps on same system. Assume host/client compromised and use app-level security control. Network security VLAN != segregated because there's too many workarounds. Use explicit firwall rules, active and passive network monitoring (snort is free), disallow end user access to production environment, have a proxy instead of direct Internet access. Also, SSL certificates are not good two-factor auth and SSL does not mean "safe." Operational Controls Have change, patch, asset, & vulnerability management (OSSI is free). For change management, always review code before pushing to production For logging, have centralized security logging for business-critical systems, separate security logging from administrative/IT logging, and lock down log (as it has everything). Monitor with OSSIM (open source). Use intrusion detection, but not just to fulfill a checkbox: build rules from a whitelist perspective (snort). OSSEC has 95% of what you need. Vulnerability management is a QA function when done right: OpenVas and Seccubus are free. Security awareness The reality is users will always click everything. Build real awareness, not compliance driven checkbox, and have it integrated into the culture. Pen test by crowd sourcing—test with logging COSSP http://www.cossp.org/ - Comprehensive Open Source Security Project What Journalists Want: The Investigative Reporters' Perspective on Hacking Dave Maas, San Diego CityBeat Jason Leopold, Truthout.org The difference between hackers and investigative journalists: For hackers, the motivation varies, but method is same, technological specialties. For investigative journalists, it's about one thing—The Story, and they need broad info-gathering skills. J-School in 60 Seconds: Generic formula: Person or issue of pubic interest, new info, or angle. Generic criteria: proximity, prominence, timeliness, human interest, oddity, or consequence. Media awareness of hackers and trends: journalists becoming extremely aware of hackers with congressional debates (privacy, data breaches), demand for data-mining Journalists, use of coding and web development for Journalists, and Journalists busted for hacking (Murdock). Info gathering by investigative journalists include Public records laws. Federal Freedom of Information Act (FOIA) is good, but slow. California Public Records Act is a lot stronger. FOIA takes forever because of foot-dragging—it helps to be specific. Often need to sue (especially FBI). CPRA is faster, and requests can be vague. Dumps and leaks (a la Wikileaks) Journalists want: leads, protecting ourselves, our sources, and adapting tools for news gathering (Google hacking). Anonomity is important to whistleblowers. They want no digital footprint left behind (e.g., email, web log). They don't trust encryption, want to feel safe and secure. Whistleblower laws are very weak—there's no upside for whistleblowers—they have to be very passionate to do it. Accessibility and Security or: How I Learned to Stop Worrying and Love the Halting Problem Anna Shubina, Dartmouth College Anna talked about how accessibility and security are related. Accessibility of digital content (not real world accessibility). mostly refers to blind users and screenreaders, for our purpose. Accessibility is about parsing documents, as are many security issues. "Rich" executable content causes accessibility to fail, and often causes security to fail. For example MS Word has executable format—it's not a document exchange format—more dangerous than PDF or HTML. Accessibility is often the first and maybe only sanity check with parsing. They have no choice because someone may want to read what you write. Google, for example, is very particular about web browser you use and are bad at supporting other browsers. Uses JavaScript instead of links, often requiring mouseover to display content. PDF is a security nightmare. Executible format, embedded flash, JavaScript, etc. 15 million lines of code. Google Chrome doesn't handle PDF correctly, causing several security bugs. PDF has an accessibility checker and PDF tagging, to help with accessibility. But no PDF checker checks for incorrect tags, untagged content, or validates lists or tables. None check executable content at all. The "Halting Problem" is: can one decide whether a program will ever stop? The answer, in general, is no (Rice's theorem). The same holds true for accessibility checkers. Language-theoretic Security says complicated data formats are hard to parse and cannot be solved due to the Halting Problem. W3C Web Accessibility Guidelines: "Perceivable, Operable, Understandable, Robust" Not much help though, except for "Robust", but here's some gems: * all information should be parsable (paraphrasing) * if not parsable, cannot be converted to alternate formats * maximize compatibility in new document formats Executible webpages are bad for security and accessibility. They say it's for a better web experience. But is it necessary to stuff web pages with JavaScript for a better experience? A good example is The Drudge Report—it has hand-written HTML with no JavaScript, yet drives a lot of web traffic due to good content. A bad example is Google News—hidden scrollbars, guessing user input. Solutions: Accessibility and security problems come from same source Expose "better user experience" myth Keep your corner of Internet parsable Remember "Halting Problem"—recognize false solutions (checking and verifying tools) Stop Patching, for Stronger PCI Compliance Adam Brand, protiviti @adamrbrand, http://www.picfun.com/ Adam talked about PCI compliance for retail sales. Take an example: for PCI compliance, 50% of Brian's time (a IT guy), 960 hours/year was spent patching POSs in 850 restaurants. Often applying some patches make no sense (like fixing a browser vulnerability on a server). "Scanner worship" is overuse of vulnerability scanners—it gives a warm and fuzzy and it's simple (red or green results—fix reds). Scanners give a false sense of security. In reality, breeches from missing patches are uncommon—more common problems are: default passwords, cleartext authentication, misconfiguration (firewall ports open). Patching Myths: Myth 1: install within 30 days of patch release (but PCI §6.1 allows a "risk-based approach" instead). Myth 2: vendor decides what's critical (also PCI §6.1). But §6.2 requires user ranking of vulnerabilities instead. Myth 3: scan and rescan until it passes. But PCI §11.2.1b says this applies only to high-risk vulnerabilities. Adam says good recommendations come from NIST 800-40. Instead use sane patching and focus on what's really important. From NIST 800-40: Proactive: Use a proactive vulnerability management process: use change control, configuration management, monitor file integrity. Monitor: start with NVD and other vulnerability alerts, not scanner results. Evaluate: public-facing system? workstation? internal server? (risk rank) Decide:on action and timeline Test: pre-test patches (stability, functionality, rollback) for change control Install: notify, change control, tickets McAfee Secure & Trustmarks — a Hacker's Best Friend Jay James, Shane MacDougall, Tactical Intelligence Inc., Canada "McAfee Secure Trustmark" is a website seal marketed by McAfee. A website gets this badge if they pass their remote scanning. The problem is a removal of trustmarks act as flags that you're vulnerable. Easy to view status change by viewing McAfee list on website or on Google. "Secure TrustGuard" is similar to McAfee. Jay and Shane wrote Perl scripts to gather sites from McAfee and search engines. If their certification image changes to a 1x1 pixel image, then they are longer certified. Their scripts take deltas of scans to see what changed daily. The bottom line is change in TrustGuard status is a flag for hackers to attack your site. Entire idea of seals is silly—you're raising a flag saying if you're vulnerable.

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