Clam AntiVirus MIME Parameter Directory Traversal Bug Lets Remote Users Overwrite Certain Files
SecurityTracker Alert ID: 1017660|
SecurityTracker URL: http://securitytracker.com/id/1017660
(Links to External Site)
Date: Feb 16 2007
Modification of user information|
Fix Available: Yes Vendor Confirmed: Yes |
Version(s): prior to 0.90 stable|
A vulnerability was reported in Clam AntiVirus. A remote user can oerwrite certain files on the target system.|
The software does not properly validate user-supplied input in the MIME header id parameter. A remote user can supply a specially crafted value containing '../' directory traversal characters to overwrite files on target system with the privileges of the clamd scanner process. Data from the MIME message body will be written to the specified file.
The vendor was notified on February 7, 2007.
iDefense reported this vulnerability.
A remote user can overwrite files on the target system with the privileges of the clamd scanner.|
The vendor has issued a fixed version (0.90 stable).|
Vendor URL: www.clamav.net/ (Links to External Site)
Input validation error|
|Underlying OS: Linux (Any), UNIX (Any)|
Source Message Contents
Subject: iDefense Security Advisory 02.15.07: Multiple Vendor ClamAV MIME|
Multiple Vendor ClamAV MIME Parsing Directory Traversal Vulnerability
iDefense Security Advisory 02.15.07
Feb 15, 2007
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
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
iDefense is unaware of any effective workarounds for this issue.
VI. VENDOR RESPONSE
Clam AntiVirus has addressed this vulnerability in the version 0.90 stable
VII. CVE INFORMATION
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
VIII. DISCLOSURE TIMELINE
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.
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