Gentoo: ClamAV Multiple Denials of Service
Posted by Benjamin D. Thomas   
Gentoo ClamAV contains several vulnerabilities leading to a Denial of Service. A remote attacker could send a specially crafted file to the scanner, possibly triggering one of the vulnerabilities. The two buffer overflows are reported to only cause Denial of Service. This would lead to a Denial of Service by CPU consumption or a crash of the scanner. The insecure temporary file creation vulnerability could be used by a local user to access sensitive data.
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Gentoo Linux Security Advisory                           GLSA 200706-05
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                                            http://security.gentoo.org/
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  Severity: Normal
     Title: ClamAV: Multiple Denials of Service
      Date: June 15, 2007
      Bugs: #178082
        ID: 200706-05

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Synopsis
========

ClamAV contains several vulnerabilities leading to a Denial of Service.

Background
==========

ClamAV is a GPL virus scanner.

Affected packages
=================

    -------------------------------------------------------------------
     Package               /  Vulnerable  /                 Unaffected
    -------------------------------------------------------------------
  1  app-antivirus/clamav      < 0.90.3                      >= 0.90.3

Description
===========

Several vulnerabilities were discovered in ClamAV by various
researchers:

* Victor Stinner (INL) discovered that the OLE2 parser may enter in
  an infinite loop (CVE-2007-2650).

* A boundary error was also reported by an anonymous researcher in
  the file unsp.c, which might lead to a buffer overflow
  (CVE-2007-3023).

* The file unrar.c contains a heap-based buffer overflow via a
  modified vm_codesize value from a RAR file (CVE-2007-3123).

* The RAR parsing engine can be bypassed via a RAR file with a header
  flag value of 10 (CVE-2007-3122).

* The cli_gentempstream() function from clamdscan creates temporary
  files with insecure permissions (CVE-2007-3024).

Impact
======

A remote attacker could send a specially crafted file to the scanner,
possibly triggering one of the vulnerabilities. The two buffer
overflows are reported to only cause Denial of Service. This would lead
to a Denial of Service by CPU consumption or a crash of the scanner.
The insecure temporary file creation vulnerability could be used by a
local user to access sensitive data.

Workaround
==========

There is no known workaround at this time.

Resolution
==========

All ClamAV users should upgrade to the latest version:

    # emerge --sync
    # emerge --ask --oneshot --verbose ">=app-antivirus/clamav-0.90.3"

References
==========

  [ 1 ] CVE-2007-2650
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-2650
  [ 2 ] CVE-2007-3023
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-3023
  [ 3 ] CVE-2007-3024
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-3024
  [ 4 ] CVE-2007-3122
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-3122
  [ 5 ] CVE-2007-3123
        http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2007-3123

Availability
============

This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:

  http://security.gentoo.org/glsa/glsa-200706-05.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
http://bugs.gentoo.org.

License
=======

Copyright 2007 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).

The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.

http://creativecommons.org/licenses/by-sa/2.5