CVE-2012-2311

Publication date 4 May 2012

Last updated 4 August 2025

Ubuntu priority

Medium

Why this priority?

sapi/cgi/cgi_main.c in PHP before 5.3.13 and 5.4.x before 5.4.3, when configured as a CGI script (aka php-cgi), does not properly handle query strings that contain a %3D sequence but no = (equals sign) character, which allows remote attackers to execute arbitrary code by placing command-line options in the query string, related to lack of skipping a certain php_getopt for the ‘d’ case. NOTE: this vulnerability exists because of an incomplete fix for CVE-2012-1823.

From the Ubuntu Security Team

It was discovered that PHP, when used as a stand alone CGI processor for the Apache Web Server, did not properly parse and filter query strings. This could allow a remote attacker to execute arbitrary code running with the privilege of the web server. Configurations using mod_php5 and FastCGI were not vulnerable.

Read the notes from the security team

Mitigation

The php-security.net article has an updated set of mod_rewrite rules that can mitigate the vulnerability as well: RewriteEngine on RewriteCond %{QUERY_STRING} ^[^=]*$ RewriteCond %{QUERY_STRING} %2d|\- [NC] RewriteRule .? - [F,L]

Status

No maintained releases are affected by this CVE.

Package Ubuntu Release Status
php5 12.04 LTS precise
Fixed 5.3.10-1ubuntu3.1
11.10 oneiric
Fixed 5.3.6-13ubuntu3.7
11.04 natty
Fixed 5.3.5-1ubuntu7.8
10.04 LTS lucid
Fixed 5.3.2-1ubuntu4.15
8.04 LTS hardy
Fixed 5.2.4-2ubuntu5.24

Notes

sbeattie

Please see http://www.php.net/archive/2012.php#id2012-05-06-1 for more details when using configurations other than as described in /usr/share/doc/php5-cgi/README.Debian.gz.