## https://sploitus.com/exploit?id=6C42C92B-E19C-567B-958C-05FF2EF60DB4
# CVE-2021-3493
Ubuntu OverlayFS Local Privesc
## Affected Versions
- Ubuntu 20.10
- Ubuntu 20.04 LTS
- Ubuntu 19.04
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 ESM
## Usage
- ```gcc exploit.c -o exploit```
- ```./exploit```
## Description
"Ubuntu specific issue in the overlayfs file system in the Linux kernel where it did not properly validate the application of file system capabilities with respect 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." [- Ubuntu Security](https://ubuntu.com/security/CVE-2021-3493)
Fixed in Linux 5.11
## References
- https://ssd-disclosure.com/ssd-advisory-overlayfs-pe/
- https://ubuntu.com/security/CVE-2021-3493
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7c03e2cda4a584cadc398e8f6641ca9988a39d52
- https://www.openwall.com/lists/oss-security/2021/04/16/1
## Disclaimer
I am not the author of this exploit. I have not made any modifications to the PoC found here: https://ssd-disclosure.com/ssd-advisory-overlayfs-pe/.