Users are urged to update their systems immediately

Jun 21, 2017 20:04 GMT  ·  By

Canonical today announced that it released a new kernel security update for the Ubuntu 12.04 LTS (Precise Pangolin) operating system series to patch the infamous Stack Clash vulnerability discovered recently by Qualys Research Labs.

Ubuntu 12.04 LTS reached end of life a few weeks ago, on April 28, 2017, but Canonical is now providing ESM (Extended Security Maintenance) updates for those still using the operating system on their machines. That's why the company is now releasing an updated kernel to fix the security issue known as Stack Clash (CVE-2017-1000364), which was already patched in all the other supported Ubuntu Linux releases.

"It was discovered that the stack guard page for processes in the Linux kernel was not sufficiently large enough to prevent overlapping with the heap. An attacker could leverage this with another vulnerability to execute arbitrary code and gain administrative privileges," reads today's USN-3338-1 security advisory.

Another security flaw patched in Linux kernel's netfilter implementation

Additionally, the kernel update fixes another security flaw (CVE-2016-4997) that was discovered by Tim Newsham and Jesse Hertz in Linux kernel's netfilter implementation, which incorrectly performed validations when attempting to handle 32-bit compatibility IPT_SO_SET_REPLACE events on 64-bit systems.

This could allow an unprivileged, local attacker to crash the affected system by causing a denial of service or execute arbitrary code with administrative (root) privileges. Canonical says that both problems can be fixed by updating your Ubuntu 12.04 LTS machines to the new kernel version (linux-image 3.2.0.128.142).

An HWE (hardware enablement) kernel from Ubuntu 14.04 LTS (Trusty Tahr) is available as well for those using Ubuntu 12.04.5 LTS, versioned linux-image-generic-lts-trusty 3.13.0.121.112. To update your systems, please follow the instructions provided by Canonical at https://wiki.ubuntu.com/Security/Upgrades.