CVE-2021-3493 PoC — Linux kernel 安全漏洞

Source

https://github.com/fei9747/CVE-2021-3493

Associated Vulnerability

Title:Linux kernel 安全漏洞 (CVE-2021-3493)
Description:Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 linux kernel 存在安全漏洞，该漏洞源于非特权用户名称空间和Ubuntu内核中允许非特权覆盖的补丁的组合，攻击者可利用该漏洞可以使用它来获得更高的特权。

Readme

# 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/.

File Snapshot


 [4.0K]  /data/pocs/f69e725c0f64cc7fb8aca72b58edcf3b7f3a9a8f
├── [3.5K]  exploit.c
└── [1.1K]  README.md

0 directories, 2 files

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