I have the following situation:

A site hosted in apache 2.4, with ssl, that works like a charm for a while now, but out of no where, without modifications to the site, apache started serving random blank pages.

The workaround this is to delete the cookies of the browser or restart the browser.

I've switched the vitualhost to log in debug mode but it didn't got me anywhere.

Here is the debug log of a failed page load:

[Wed Oct 24 10:57:35.762547 2012] [ssl:info] [pid 27854:tid 140617706374912] [client 192.168.10.150:58917] AH01964: Connection to child 147 established (server xxx.com.br:443)
[Wed Oct 24 10:57:35.762739 2012] [ssl:debug] [pid 27854:tid 140617706374912] ssl_engine_kernel.c(1966): [client 192.168.10.150:58917] AH02043: SSL virtual host for servername xxx.com.br found
[Wed Oct 24 10:57:35.777479 2012] [ssl:debug] [pid 27854:tid 140617706374912] ssl_engine_kernel.c(1899): [client 192.168.10.150:58917] AH02041: Protocol: TLSv1, Cipher: DHE-RSA-AES256-SHA (256/256 bits)
[Wed Oct 24 10:57:35.779912 2012] [ssl:debug] [pid 27854:tid 140617706374912] ssl_engine_kernel.c(243): [client 192.168.10.150:58917] AH02034: Initial (No.1) HTTPS request received for child 147 (server xxx.com.br:443)
[Wed Oct 24 10:57:35.780044 2012] [authz_core:debug] [pid 27854:tid 140617706374912] mod_authz_core.c(809): [client 192.168.10.150:58917] AH01628: authorization result: granted (no directives)
[Wed Oct 24 10:57:40.783950 2012] [ssl:info] [pid 27854:tid 140617706374912] (70007)The timeout specified has expired: [client 192.168.10.150:58917] AH01991: SSL input filter read failed.
[Wed Oct 24 10:57:40.784077 2012] [ssl:debug] [pid 27854:tid 140617706374912] ssl_engine_io.c(988): [remote 192.168.10.150:58917] AH02001: Connection closed to child 147 with standard shutdown (server xxx.com.br:443)