CVE-2011-4415 Information

Description

The ap_pregsub function in server/util.c in the Apache HTTP Server 2.0.x through 2.0.64 and 2.2.x through 2.2.21 when the mod_setenvif module is enabled does not restrict the size of values of environment variables which allows local users to cause a denial of service (memory consumption or NULL pointer dereference) via a .htaccess file with a crafted SetEnvIf directive in conjunction with a crafted HTTP request header related to (1) the \len +=\ statement and (2) the apr_pcalloc function call a different vulnerability than CVE-2011-3607.

Reference

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c03360041 http://www.gossamer-threads.com/lists/apache/dev/403775 http://www.halfdog.net/Security/2011/ApacheModSetEnvIfIntegerOverflow/ http://www.halfdog.net/Security/2011/ApacheModSetEnvIfIntegerOverflow/DemoExploit.html