A recent Linux vulnerability was found with Grub bootloader. Grub2 bootloader version 1.98 from nineteen ninety nine to version 2.02 December of two thousand fifteen has a potential security hole. Users can potentially bypass any plain or hashed password authentication.
This would allow someone to take control of your Linux based computer. Grub2 is used by most modern Linux systems. You can test this vulnerability on your Linux machine by pressing a backspace twenty eight times at Grub's username login box. If your computer reboots or drops into a rescue shell, then your machine is affected by this security hole.
A grub rescue shell allows:
* Elevation of privilege: allows full access to grub shell commands
* Information disclosure: allows installation of a rootkit and or ability to copy entire hard disk contents
* Denial of service: allows any and all data to become destroyed even grub itself
This actual bug is quite a bit more convoluted and complex than this blog post. However, you can check out this detailed Grub2 authentication bypass article. Malware and infections can be installed on a Linux machine without an owner's knowledge.
Currently, there is a username password vulnerability patch for Grub2 version 2.02 from Github. Successfully exploitating this security hole depends on the Basic Input Output System version, GRand Unified Bootloader version, amount of Random Access Memory, and whatever modifies that computer's memory layout. This flaw allows a potential physical security risk.
Users should install any Grub2 related updates available as soon as possible. Major linux vendors such as Debian, Red Hat, and Ubuntu have released patches for this security flaw. Obviously, not allowing physical access to your Linux machine(s) is one way to avoid this security bug being exploited.