Clam AntiVirus ENSURE_BITS function denial of service
| clam-antivirus-ensurebits-dos (21204) |  Low Risk |
Description:
Clam AntiVirus is vulnerable to a denial of service attack caused by improper validation of user-supplied input in the ENSURE_BITS() function in the libclamav/mspack/mszipd.c. A remote attacker could send a specially-crafted CAB file with a cffile_FolderOffset set to 0xff to cause the program to enter an infinite loop, resulting in a denial of service.
Platforms Affected:
- Clam Anti-Virus, ClamAV 0.83
- Clam Anti-Virus, ClamAV prior to 0.86
- Debian, Debian Linux 3.1
Remedy:
Upgrade to the latest version of Clam AntiVirus (0.86 or later), available from the ClamAV Download Web page. See References.
For Debian GNU/Linux 3.1 (Sarge):
Upgrade to the latest version of clamav (0.84-2.sarge.1 or later), as listed in DSA-737-1. See Reference.
For Conectiva Linux 9.0 and 10.0:
Upgrade to the latest version of clamav (0.86.1 or later), as listed in Conectiva Linux Security Announcement CLSA-2005:973. See References.
As a workaround, follow the instructions as listed in iDEFENSE Security Advisory 06.29.05. See References.
Consequences:
Denial of Service
References:
- ClamAV Download Web page, clamav 0.86.1 released at http://www.clamav.net/stable.php#pagestart.
- Conectiva Linux Security Announcement CLSA-2005:973, Fixes for two security vulnerabilities in clamav at http://distro.conectiva.com/atualizacoes/index.php?id=a&anuncio=000973.
- iDEFENSE Security Advisory 06.29.05, Clam AntiVirus ClamAV Cabinet File Handling DoS Vulnerability at http://www.idefense.com/application/poi/display?id=275&type=vulnerabilities&flashstatus=true.
- BID-14089: Clam Anti-Virus ClamAV Cabinet File Parsing Remote Denial Of Service Vulnerability
- BID-14090: Clam Anti-Virus ClamAV MS-Expand File Parsing Remote Denial Of Service Vulnerability
- CVE-2005-1923: The ENSURE_BITS macro in mszipd.c for Clam AntiVirus (ClamAV) 0.83, and other versions vefore 0.86, allows remote attackers to cause a denial of service (CPU consumption by infinite loop) via a cabinet (CAB) file with the cffile_FolderOffset field set to 0xff, which causes a zero-length read.
- DSA-737: clamav -- remote denial of service
Reported:
Jun 29, 2005
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