-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 - ------------------------------------------------------------ Arch Linux Security Warning ALSW 2007-#9 - ------------------------------------------------------------
Name: clamav Date: 2007-02-15 Severity: Normal Warning #: 2007-#9 - ------------------------------------------------------------ Product Background =================== Clam AntiVirus is a multi-platform GPL anti-virus toolkit. The main purpose of which is integration into electronic mail servers. More information about ClamAV can be found at http://clamav.net/. Problem Background =================== Remote exploitation of a resource consumption vulnerability in Clam AntiVirus' ClamAV allows attackers to degrade the service of the clamd scanner. The vulnerability specifically exists due to a file descriptor leak. When clam encounters a cabinet header with a record length of zero it will return from a function without closing a local file descriptor. This can be triggered multiple times, eventually using up all but three of its available file descriptors. This prevents clam from scanning most archives, including zip and tar files. (CVE-2007-0897) 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.(CVE-2007-0898) Impact ====== Exploitation allows attackers to degrade the functionality of the ClamAV virus scanning service. Exploitation requires that attackers send a specially constructed CAB file through an e-mail gateway or personal anti-virus client using the ClamAV scanning engine. When ClamAV is unable to scan an archive successfully because it has run out of descriptors, it will return an error status. Several mail servers that use clam were tested to see how they handled this status. Exim, as of version 4.50, features an option to build clamd support into it. It will reject a mail if clamd fails to scan it properly. Amavisd will also deny a mail that clamd cannot properly scan. This vulnerability can be used to deny service to users trying to send legitimate archives through the mail gateway. (CVE-2007-0897) 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. (CVE-2007-0898) Problem Packages =================== - ------------------------------------------------------------------ Package | Repo | Group | Unsafe | Safe | - ------------------------------------------------------------------ clamav extra system < 0.90 >= 0.90 Package Fix =================== Upgrade to ClamAV 0.90. Source: http://dl.sourceforge.net/clamav/clamav-0.90.tar.gz Reference(s) =================== http://cve.mitre.org/cgi-bin/cvename.cgi?name=2007-0897 http://cve.mitre.org/cgi-bin/cvename.cgi?name=2007-0898 Contact =================== JJDaNiMoTh (jjdanimoth AT gmail DOT com) -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFF1Mg6cJj0HNhER0MRAvlOAJ9cXatBWV71HrWdn8X2qNsuuMbPowCdEgVQ HjLa/iI0sqoPW2cEromKbXc= =GOpp -----END PGP SIGNATURE----- _______________________________________________ arch mailing list arch@archlinux.org http://www.archlinux.org/mailman/listinfo/arch
