GLSA 200402-07: Clam Antivirus DoS vulnerability

http://security.gentoo.org/

Severity:	normal
Title:	Clam Antivirus DoS vulnerability
Date:	02/17/2004
Bugs:	#41248
ID:	200402-07

Synopsis

Oliver Eikemeier has reported a vulnerability in Clam AV, which can be exploited by a malformed uuencoded message causing a denial of service for programs that rely on the clamav daemon, such as SMTP daemons.

Background

Clam AntiVirus is a GPLed anti-virus toolkit, designed for integration with mail servers to perform attachment scanning. Clam AV also provides a command line scanner and a tool for fetching updates of the virus database.

Affected packages

Package	Vulnerable	Unaffected	Architecture(s)
app-antivirus/clamav	< 0.67	>= 0.67	All supported architectures

Description

Oliver Eikemeier of Fillmore Labs discovered the overflow in Clam AV 0.65 when it handled malformed UUEncoded messages, causing the daemon to shut down.

The problem originated in libclamav which calculates the line length of an uuencoded message by taking the ASCII value of the first character minus 64 while doing an assertion if the length is not in the allowed range, effectively terminating the calling program as clamav would not be available.

Impact

A malformed message would cause a denial of service, and depending on the server configuration this may impact other daemons relying on Clam AV in a fatal manner.

Workaround

There is no immediate workaround, a software upgrade is required.

Resolution

All users are urged to upgrade their Clam AV installations to Clam AV 0.67:

    # emerge sync
    # emerge -pv ">=app-antivirus/clamav-0.6.7"
    # emerge ">=app-antivirus/clamav-0.6.7"

References

Availability

This GLSA and any updates to it are available for viewing at the Gentoo Security Website: http://security.gentoo.org/glsa/glsa-200402-07.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.