Exim verify=header_syntax buffer overflow
Gentoo Linux Security Advisory
||GLSA 200405-07 / Exim
||May 14, 2004
||May 14, 2004: 01
All supported architectures
When the verify=header_syntax option is set, there is a buffer overflow in
Exim that allows remote execution of arbitrary code.
Exim is an highly configurable message transfer agent (MTA) developed at
the University of Cambridge.
When the option "verify = header_syntax" is used in an ACL in the
configuration file, Exim is vulnerable to a buffer overflow attack that can
be triggered remotely by sending malicious headers in an email message.
Note that this option is not enabled in Exim's default configuration file.
This vulnerability can be exploited to trigger a denial of service attack
and potentially execute arbitrary code with the rights of the user used by
the Exim daemon (by default this is the "mail" user in Gentoo Linux).
Make sure the verify=header_syntax option is not used in your exim.conf
All users of Exim should upgrade to the latest stable version:
Code Listing 3.1: Resolution
# emerge sync
# emerge -pv ">=mail-mta/exim-4.33-r1"
# emerge ">=mail-mta/exim-4.33-r1"