Multiple kernel flaws have been fixed.
It was discovered that the /proc filesystem did not correctly handle permission changes when programs executed. A local attacker could hold open files to examine details about programs running with higher privileges, potentially increasing the chances of exploiting additional vulnerabilities. (CVE-2011-1020)
21 September 2011
A security issue affects these releases of Ubuntu and its derivatives:
Multiple kernel flaws have been fixed.
It was discovered that the /proc filesystem did not correctly handle permission changes when programs executed. A local attacker could hold open files to examine details about programs running with higher privileges, potentially increasing the chances of exploiting additional vulnerabilities. (CVE-2011-1020)
Dan Rosenberg discovered that the X.25 Rose network stack did not correctly handle certain fields. If a system was running with Rose enabled, a remote attacker could send specially crafted traffic to gain root privileges. (CVE-2011-1493)
Vasiliy Kulikov and Dan Rosenberg discovered that ecryptfs did not correctly check the origin of mount points. A local attacker could exploit this to trick the system into unmounting arbitrary mount points, leading to a denial of service. (CVE-2011-1833)
It was discovered that Bluetooth l2cap and rfcomm did not correctly initialize structures. A local attacker could exploit this to read portions of the kernel stack, leading to a loss of privacy. (CVE-2011-2492)
It was discovered that GFS2 did not correctly check block sizes. A local attacker could exploit this to crash the system, leading to a denial of service. (CVE-2011-2689)
Fernando Gont discovered that the IPv6 stack used predictable fragment identification numbers. A remote attacker could exploit this to exhaust network resources, leading to a denial of service. (CVE-2011-2699)
The performance counter subsystem did not correctly handle certain counters. A local attacker could exploit this to crash the system, leading to a denial of service. (CVE-2011-2918)
A flaw was found in the Linux kernel’s /proc/*/map interface. A local, unprivileged user could exploit this flaw to cause a denial of service. (CVE-2011-3637)
Ben Hutchings discovered several flaws in the Linux Rose (X.25 PLP) layer. A local user or a remote user on an X.25 network could exploit these flaws to execute arbitrary code as root. (CVE-2011-4914)
The problem can be corrected by updating your system to the following package versions:
To update your system, please follow these instructions: https://wiki.ubuntu.com/Security/Upgrades.
After a standard system update you need to reboot your computer to make all the necessary changes.
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