Debian Security Advisory
DSA-2305-1 vsftpd -- denial of service
- Date Reported:
- 19 Sep 2011
- Affected Packages:
- Security database references:
- In the Debian bugtracking system: Bug 622741, Bug 629373.
In Mitre's CVE dictionary: CVE-2011-0762, CVE-2011-2189.
- More information:
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. 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.
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.