16-year-old Januscape vulnerability found in the Linux kernel enables virtual machine escape

Security researchers have discovered a vulnerability in the Linux kernel that has been named Januscape. According to available information, the flaw went unnoticed for 16 years.

The vulnerability affects systems based on Intel and AMD processors. It allows an attacker to perform a virtual machine escape (VM escape) and run arbitrary code directly on the host system, bypassing the isolation that virtualization is supposed to provide.

Why it's dangerous

A virtual machine escape is considered one of the most serious classes of vulnerabilities in cloud and virtualized environments. Isolation between guest systems and the host is a key security mechanism that cloud service providers and data center operators rely on when different customers share the same physical hardware.

If an attacker is able to break out of a virtual machine, it puts at risk not only the data and processes of the specific guest, but potentially also the other virtual machines running on the same physical server.

The fact that the vulnerability remained in the Linux kernel for 16 years underscores how difficult it is to audit the low-level code responsible for virtualization and for working with hardware from different manufacturers.

Details about the technical nature of the vulnerability, the status of fixes, and the affected kernel versions are still limited.

Source: Bleeping Computer