Clam AntiVirus is a multi-platform GPL anti-virus toolkit. ClamAV is often integrated into mail gateways, and used to scan mail traffic for viruses. More information about ClamAV is available from http://clamav.net/. Multipurpose Internet Mail Extensions (MIME), is an internet standard for sending email with non-text attachments, multi-part message bodies, and non-ASCII character sets.
Remote exploitation of a directory traversal vulnerability in Clam AntiVirus' ClamAV allows attackers to overwrite files owned by the clamd scanner.
The vulnerability specifically exists due to the lack of validation of the id parameter string taken from a MIME header. When parsing a multi-part message clam takes this string from the header and uses it to create a local file. By sending a string such as "../../../../some/file" an attacker can create or overwrite an arbitrary file owned by the clamd process. Data from the message body is later written to this file.
Exploitation allows attackers to degrade the service of the ClamAV virus scanning service. The most important mitigating factor is that the clam process runs with the privileges of the clamav user and group. This group has access to a limited subset of files on the host. A possible target for overwriting is the virus database file. By overwriting this file an attacker could then send a virus through the gateway without clam recognizing it; this effectively denies service. Arbitrary viruses will be allowed to pass through, creating a false sense of security.
iDefense has confirmed this vulnerability affects Clam AntiVirus ClamAV v0.88.6. All versions prior to the 0.90 stable release are suspected to be vulnerable.
iDefense is unaware of any effective workarounds for this issue.
Clam AntiVirus has addressed this vulnerability in the version 0.90 stable release.
The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-0898 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems.
02/07/2007 Initial vendor notification
02/13/2007 Initial vendor response
02/15/2007 Coordinated public disclosure
The discoverer of this vulnerability wishes to remain anonymous.
Get paid for vulnerability research
Free tools, research and upcoming events
Copyright © 2006 Verisign, Inc.
Permission is granted for the redistribution of this alert electronically. It may not be edited in any way without the express written consent of iDefense. If you wish to reprint the whole or any part of this alert in any other medium other than electronically, please e-mail customer service for permission.
Disclaimer: The information in the advisory is believed to be accurate at the time of publishing based on currently available information. Use of the information constitutes acceptance for use in an AS IS condition. There are no warranties with regard to this information. Neither the author nor the publisher accepts any liability for any direct, indirect, or consequential loss or damage arising from use of, or reliance on, this information.