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Debian: Security update for vsftpd

Two security issue have been discovered that affect vsftpd, a lightweight, efficient FTP server written for security. It was discovered that Linux kernels < 2.6.35 are considerably slower in releasing than in the creation of network namespaces. As a result of this and because vsftpd is using this feature as a security enhancement to provide network isolation for connections, it is possible to cause denial of service conditions due to excessive memory allocations by the kernel. Maksymilian Arciemowicz discovered that vsftpd is incorrectly handling certain glob expressions in STAT commands. This allows a remote authenticated attacker to conduct denial of service attacks (excessive CPU and process slot exhaustion) via crafted STAT commands. Updated packages are available from security.debian.org.

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Debian Security Advisory DSA-2305-1                    security@debian.org
http://www.debian.org/security/                                 Nico Golde
September 19, 2011                      http://www.debian.org/security/faq
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Package        : vsftpd
Vulnerability  : denial of service
Problem type   : remote
Debian-specific: no
Debian bug     : 622741 629373
CVE IDs        : CVE-2011-0762 CVE-2011-2189

Two security issue have been discovered that affect vsftpd, a lightweight,
efficient FTP server written for security.

CVE-2011-2189

   It was discovered that Linux kernels < 2.6.35 are considerably slower in
   releasing than in the creation of network namespaces.  As a result of this
   and because vsftpd is using this feature as a security enhancement to
   provide network isolation for connections, it is possible to cause denial
   of service conditions due to excessive memory allocations by the kernel.
   This is technically no vsftpd flaw, but a kernel issue.  However, this
   feature has legitimate use cases and backporting the specific kernel patch
   is too intrusive.  Additionally, a local attacker requires the CAP_SYS_ADMIN
   capability to abuse this functionality.  Therefore, as a fix, a kernel
   version check has been added to vsftpd in order to disable this feature
   for kernels < 2.6.35.

CVE-2011-0762

   Maksymilian Arciemowicz discovered that vsftpd is incorrectly handling
   certain glob expressions in STAT commands.  This allows a remote authenticated
   attacker to conduct denial of service attacks (excessive CPU and process
   slot exhaustion) via crafted STAT commands.

For the oldstable distribution (lenny), this problem has been fixed in
version 2.0.7-1+lenny1.

For the stable distribution (squeeze), this problem has been fixed in
version 2.3.2-3+squeeze2.  Please note that CVE-2011-2189 does not affect
the lenny version.

For the testing distribution (wheezy), this problem will be fixed soon.

For the unstable distribution (sid), this problem has been fixed in
version 2.3.4-1.

We recommend that you upgrade your vsftpd packages.

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: http://www.debian.org/security/

Mailing list: debian-security-announce@lists.debian.org
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