GRUB2 Authentication Bypass Vulnerability

A vulnerability has been discovered in the GRUB2 boot loader that affects versions dating back to 2009. GRUB2 is the default boot loader for a variety of popular Linux distributions including Ubuntu, Red Hat and Debian. The vulnerability can be exploited by pressing the backspace button 28 times when the boot loader asks for your username. This sequence of keys places the user into a “rescue shell”. An attacker could¬†leverage this shell to access confidential data or install persistent malware.

It’s worth noting that the vulnerability requires access to the system’s console. Even if your organization has proper physical security controls in place, this issue should still be addressed as soon as possible. Ubuntu, RedHat and Debian have already released patches for this vulnerability.

Got MS DNS Servers? Get the Patch ASAP!

If you run DNS on Microsoft Windows, pay careful attention to the MS-15-127 patch.

Microsoft rates this patch as critical for most Windows platforms running DNS services.

Remote exploits are possible, including remote code execution. Attackers exploiting this issue could obtain Local System context and privileges.

We are currently aware that reverse engineering of the patch has begun by researchers and exploit development is under way in the underground pertaining to this issue. A working exploit is likely to be made available soon, if it is not already in play, as you read this.