Users are urged to update as soon as possible

Oct 1, 2015 21:47 GMT  ·  By

Today, October 1, Canonical announced the general availability of a new kernel update for its long-term supported Ubuntu 12.04 LTS (Precise Pangolin) computer operating system, patching three critical Linux kernel vulnerabilities.

The first kernel vulnerability was discovered in Linux kernel's SCSI generic (sg) driver as an integer overflow error that could allow a local attacker that had write permissions to the SCSI generic device to crash the target system by causing a denial of service (DoS) condition, as well as to gain root access.

The second security flaw was discovered by Marc-André Lureau in Linux kernel's vhost driver, which apparently did not correctly release the userspace provided log file descriptor, allowing a privileged attacker to cause a DoS (Denial of Service) attack on the target system.

Last but not least, the third kernel vulnerability was discovered in Linux kernel's perf subsystem, which didn't bound callchain backtraces on the PowerPC 64 (PPC64) hardware architecture, allowing a local attacker to cause a Denial of Service (DoS) attack on the target system.

Ubuntu 12.04 LTS users are urged to update immediately

The security flaws have been discovered by various developers in the upstream Linux 3.2 LTS kernel branch and appear to affect Ubuntu 12.04 LTS and its derivatives, but also any other GNU/Linux distribution that uses a kernel from the Linux 3.2 series. More details can be found at CVE-2015-5707, CVE-2015-6252, and CVE-2015-6526.

Canonical urges all users of the Ubuntu 12.04 LTS (Precise Pangolin) operating system and its derivatives that use the Linux 3.2.0 kernel packages to upgrade immediately to linux-image-3.2.0-91 (3.2.0-91.129). To do so, run the Software Updater utility from the Unity Dash, and apply all existing updates.

Make sure that you reboot your computer after the update. To check if your kernel matches the one above, run the "uname -a" command in the Terminal app. Also, it is imperative that you rebuild any third-party kernel modules you may have installed on your system.