GLSA 200405-03: ClamAV VirusEvent parameter vulnerability

http://security.gentoo.org/

Severity:	high
Title:	ClamAV VirusEvent parameter vulnerability
Date:	05/11/2004
Bugs:	#46264
ID:	200405-03

Synopsis

With a specific configuration (using %f in the VirusEvent parameter), Clam AntiVirus is vulnerable to an attack allowing execution of arbitrary commands.

Background

From http://www.clamav.net/ :

"Clam AntiVirus is a GPL anti-virus toolkit for UNIX. The main purpose of this software is the integration with mail servers (attachment scanning). The package provides a flexible and scalable multi-threaded daemon, a command line scanner, and a tool for automatic updating via Internet. The programs are based on a shared library distributed with the Clam AntiVirus package, which you can use with your own software. Most importantly, the virus database is kept up to date."

Affected packages

Package	Vulnerable	Unaffected	Architecture(s)
app-antivirus/clamav	< 0.70	>= 0.70	All supported architectures

Description

The VirusEvent parameter in the clamav.conf configuration file allows to specify a system command to run whenever a virus is found. This system command can make use of the "%f" parameter which is replaced by the name of the file infected. The name of the file scanned is under control of the attacker and is not sufficiently checked. Version 0.70 of clamav disables the use of the "%f" parameter.

Impact

Sending a virus with a malicious file name can result in execution of arbirary system commands with the rights of the antivirus process. Since clamav is often associated to mail servers for email scanning, this attack can be used remotely.

Workaround

You should not use the "%f" parameter in your VirusEvent configuration.

Resolution

All users of Clam AntiVirus should upgrade to the latest stable version:

    # emerge sync
    
    # emerge -pv ">=app-antivirus/clamav-0.70"
    # emerge ">=app-antivirus/clamav-0.70"

References

CVE-2004-1876

Availability

This GLSA and any updates to it are available for viewing at the Gentoo Security Website: http://security.gentoo.org/glsa/glsa-200405-03.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.