GLSA 200501-23: Exim: Two buffer overflows

http://security.gentoo.org/

Severity:	high
Title:	Exim: Two buffer overflows
Date:	01/12/2005
Bugs:	#76893
ID:	200501-23

Synopsis

Buffer overflow vulnerabilities, which could lead to arbitrary code execution, have been found in the handling of IPv6 addresses as well as in the SPA authentication mechanism in Exim.

Background

Exim is an highly configurable message transfer agent (MTA) developed at the University of Cambridge.

Affected packages

Package	Vulnerable	Unaffected	Architecture(s)
mail-mta/exim	< 4.43-r2	>= 4.43-r2	All supported architectures

Description

Buffer overflows have been found in the host_aton() function (CAN-2005-0021) as well as in the spa_base64_to_bits() function (CAN-2005-0022), which is part of the SPA authentication code.

Impact

A local attacker could trigger the buffer overflow in host_aton() by supplying an illegal IPv6 address with more than 8 components, using a command line option. The second vulnerability could be remotely exploited during SPA authentication, if it is enabled on the server. Both buffer overflows can potentially lead to the execution of arbitrary code.

Workaround

There is no known workaround at this time.

Resolution

All Exim users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=mail-mta/exim-4.43-r2"

References

Availability

This GLSA and any updates to it are available for viewing at the Gentoo Security Website: http://security.gentoo.org/glsa/glsa-200501-23.xml

Concerns?

Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org.