ZDI-06-001: Clam AntiVirus UPX Unpacking Code Execution Vulnerability
January 12, 2006
-- CVE ID:
-- Affected Vendor:
-- Affected Products:
Clam AntiVirus 0.80 through 0.87.1
-- TippingPoint(TM) IPS Customer Protection:
TippingPoint IPS customers have been protected against this
vulnerability since December 13, 2005 by Digital Vaccine protection
filter ID 3975. For further product information on the TippingPoint IPS:
-- Vulnerability Details:
This vulnerability allows remote attackers to execute arbitrary code on
vulnerable ClamAV installations. Authentication is not required to
exploit this vulnerability.
This specific flaw exists within libclamav/fsg.c during the unpacking of
executable files compressed with FSG v1.33. Due to invalid bounds
checking when copying user-supplied data to heap allocated memory, an
exploitable memory corruption condition is created. The unpacking
algorithm for other versions of FSG is not affected.
-- Vendor Response:
Addressed in Clam AntiVirus version 0.88:
-- Disclosure Timeline:
2005.13.12 - Vulnerability reported to vendor
2005.13.12 - Digital Vaccine released to TippingPoint customers
2006.12.01 - Public release of advisory
This vulnerability was discovered by an anonymous researcher.
-- About the Zero Day Initiative (ZDI):
Established by TippingPoint, a division of 3Com, The Zero Day Initiative
(ZDI) represents a best-of-breed model for rewarding security
researchers for responsibly disclosing discovered vulnerabilities.
Researchers interested in getting paid for their security research
through the ZDI can find more information and sign-up at:
The ZDI is unique in how the acquired vulnerability information is used.
3Com does not re-sell the vulnerability details or any exploit code.
Instead, upon notifying the affected product vendor, 3Com provides its
customers with zero day protection through its intrusion prevention
technology. Explicit details regarding the specifics of the
vulnerability are not exposed to any parties until an official vendor
patch is publicly available. Furthermore, with the altruistic aim of
helping to secure a broader user base, 3Com provides this vulnerability
information confidentially to security vendors (including competitors)
who have a vulnerability protection or mitigation product.