Ubuntu OverlayFS Local Privesc Vulnerability

The CVE-2021-3493 is an Ubuntu-specific issue in the overlayfs file system in the Linux kernel where there is a lack of proper validation of the application file system capabilities to user namespaces. A local attacker could use this to gain elevated privileges, due to a patch carried in Ubuntu to allow unprivileged overlayfs mounts.

Key Pointers:

• Understanding important key points used throughout the paper
• The severity and scope of impact of this vulnerability
• Learning about the mitigations for different Ubuntu versions
• Setting up the lab environment and demonstrating the exploitation method