Debian DSA-2303-2 : linux-2.6 - privilege escalation/denial of service/information leak

critical Nessus Plugin ID 56130


The remote Debian host is missing a security-related update.


Several vulnerabilities have been discovered in the Linux kernel that may lead to a denial of service or privilege escalation. The Common Vulnerabilities and Exposures project identifies the following problems :

- CVE-2011-1020 Kees Cook discovered an issue in the /proc filesystem that allows local users to gain access to sensitive process information after execution of a setuid binary.

- CVE-2011-1576 Ryan Sweat discovered an issue in the VLAN implementation. Local users may be able to cause a kernel memory leak, resulting in a denial of service.

- CVE-2011-2484 Vasiliy Kulikov of Openwall discovered that the number of exit handlers that a process can register is not capped, resulting in local denial of service through resource exhaustion (CPU time and memory).

- CVE-2011-2491 Vasily Averin discovered an issue with the NFS locking implementation. A malicious NFS server can cause a client to hang indefinitely in an unlock call.

- CVE-2011-2492 Marek Kroemeke and Filip Palian discovered that uninitialized struct elements in the Bluetooth subsystem could lead to a leak of sensitive kernel memory through leaked stack memory.

- CVE-2011-2495 Vasiliy Kulikov of Openwall discovered that the io file of a process' proc directory was world-readable, resulting in local information disclosure of information such as password lengths.

- CVE-2011-2496 Robert Swiecki discovered that mremap() could be abused for local denial of service by triggering a BUG_ON assert.

- CVE-2011-2497 Dan Rosenberg discovered an integer underflow in the Bluetooth subsystem, which could lead to denial of service or privilege escalation.

- CVE-2011-2517 It was discovered that the netlink-based wireless configuration interface performed insufficient length validation when parsing SSIDs, resulting in buffer overflows. Local users with the CAP_NET_ADMIN capability can cause a denial of service.

- CVE-2011-2525 Ben Pfaff reported an issue in the network scheduling code. A local user could cause a denial of service (NULL pointer dereference) by sending a specially crafted netlink message.

- CVE-2011-2700 Mauro Carvalho Chehab of Red Hat reported a buffer overflow issue in the driver for the Si4713 FM Radio Transmitter driver used by N900 devices. Local users could exploit this issue to cause a denial of service or potentially gain elevated privileges.

- CVE-2011-2723 Brent Meshier reported an issue in the GRO (generic receive offload) implementation. This can be exploited by remote users to create a denial of service (system crash) in certain network device configurations.

- CVE-2011-2905 Christian Ohm discovered that the 'perf' analysis tool searches for its config files in the current working directory. This could lead to denial of service or potential privilege escalation if a user with elevated privileges is tricked into running 'perf' in a directory under the control of the attacker.

- CVE-2011-2909 Vasiliy Kulikov of Openwall discovered that a programming error in the Comedi driver could lead to the information disclosure through leaked stack memory.

- CVE-2011-2918 Vince Weaver discovered that incorrect handling of software event overflows in the 'perf' analysis tool could lead to local denial of service.

- CVE-2011-2928 Timo Warns discovered that insufficient validation of Be filesystem images could lead to local denial of service if a malformed filesystem image is mounted.

- CVE-2011-3188 Dan Kaminsky reported a weakness of the sequence number generation in the TCP protocol implementation. This can be used by remote attackers to inject packets into an active session.

- CVE-2011-3191 Darren Lavender reported an issue in the Common Internet File System (CIFS). A malicious file server could cause memory corruption leading to a denial of service.

This update also includes a fix for a regression introduced with the previous security fix for CVE-2011-1768 (Debian bug #633738).


Upgrade the linux-2.6 and user-mode-linux packages.

For the stable distribution (squeeze), this problem has been fixed in version 2.6.32-35squeeze2. Updates for issues impacting the oldstable distribution (lenny) will be available soon.

The following matrix lists additional source packages that were rebuilt for compatibility with or to take advantage of this update :

Debian 6.0 (squeeze) user-mode-linux 2.6.32-1um-4+35squeeze2

See Also

Plugin Details

Severity: Critical

ID: 56130

File Name: debian_DSA-2303.nasl

Version: 1.20

Type: local

Agent: unix

Published: 9/9/2011

Updated: 1/11/2021

Supported Sensors: Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information


Risk Factor: Medium

Score: 6.4


Risk Factor: Critical

Base Score: 10

Temporal Score: 8.7

Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C

Vulnerability Information

CPE: p-cpe:/a:debian:debian_linux:linux-2.6, cpe:/o:debian:debian_linux:6.0

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 9/10/2011

Vulnerability Publication Date: 2/28/2011

Reference Information

CVE: CVE-2011-1020, CVE-2011-1576, CVE-2011-2484, CVE-2011-2491, CVE-2011-2492, CVE-2011-2495, CVE-2011-2496, CVE-2011-2497, CVE-2011-2517, CVE-2011-2525, CVE-2011-2700, CVE-2011-2723, CVE-2011-2905, CVE-2011-2909, CVE-2011-2918, CVE-2011-2928, CVE-2011-3188, CVE-2011-3191

BID: 46567, 47321, 48383, 48441, 48472, 48538, 48641, 48804, 48907, 48929, 49140, 49141, 49152, 49256, 49289, 49295, 49408, 49411

DSA: 2303