[NEWS] Apache ssl_callback_SSLVerify_CRL DoS

The following security advisory is sent to the securiteam mailing list, and can 
be found at the SecuriTeam web site: http://www.securiteam.com
- - promotion

The SecuriTeam alerts list - Free, Accurate, Independent.

Get your security news from a reliable source.
http://www.securiteam.com/mailinglist.html 

- - - - - - - - -



  Apache ssl_callback_SSLVerify_CRL DoS
------------------------------------------------------------------------


SUMMARY

"Apache is one of the the world's most widely used Web servers. Originally 
developed in 1995 by a group that was to go on to become the The Apache 
Group, the Apache HTTP Server is Open Source Software, and considered by 
proponents to be fast, scalable and secure. The name was derived from the 
project's less robust beginnings ('A patchy Web server')."

A buffer overrun vulnerability was recently reported in Apache, this 
vulnerability could be exploited by malicious attackers to cause a denial 
of service.

DETAILS

Vulnerable Systems:
 * Apache HTTP Server version 2.0.54

Immune Systems:
 * Apache HTTP Server version 2.0.55

A buffer overrun can be found in ssl_callback_SSLVerify_CRL( ) - 
ssl_engine_kernel.c:
char buff[512]; /* should be plenty */
[...]
n = BIO_read(bio, buff, sizeof(buff));
buff[n] = '\0';

If there are more than 512 bytes the resulting value of n is 512, causing 
us to write at location 512 (buff[512]) overflowing the buffer by one. The 
line should read:
    n = BIO_read(bio, buff, sizeof(buff) - 1);


ADDITIONAL INFORMATION

The original article can be found at:  
<http://issues.apache.org/bugzilla/show_bug.cgi?id=35081> 
http://issues.apache.org/bugzilla/show_bug.cgi?id=35081



======================================== 


This bulletin is sent to members of the SecuriTeam mailing list. 
To unsubscribe from the list, send mail with an empty subject line and body to: 
list-unsubscribe@xxxxxxxxxxxxxx 
In order to subscribe to the mailing list, simply forward this email to: 
list-subscribe@xxxxxxxxxxxxxx 


==================== 
==================== 

DISCLAIMER: 
The information in this bulletin is provided "AS IS" without warranty of any 
kind. 
In no event shall we be liable for any damages whatsoever including direct, 
indirect, incidental, consequential, loss of business profits or special 
damages.