Lighttpd: Buffer overflow

Background

Lighttpd is a lightweight HTTP web server.

Description

Mattias Bengtsson and Philip Olausson have discovered a buffer overflow vulnerability in the function fcgi_env_add() in the file mod_fastcgi.c when processing overly long HTTP headers.

Impact

A remote attacker could send a specially crafted request to the vulnerable Lighttpd server, resulting in the remote execution of arbitrary code with privileges of the user running the web server. Note that mod_fastcgi is disabled in Gentoo’s default configuration.

Workaround

Edit the file /etc/lighttpd/lighttpd.conf and comment the following line: “include mod_fastcgi.conf”

Resolution

All Lighttpd users should upgrade to the latest version:

 # emerge --sync
 # emerge --ask --oneshot --verbose ">=www-servers/lighttpd-1.4.18"