CVE-2021-4034 PoC — polkit 缓冲区错误漏洞

Source

https://github.com/Al1ex/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

Local Privilege Escalation in polkit's pkexec (CVE-2021-4034)

Readme

### Information

```
Exploit Title: Local Privilege Escalation in polkit's pkexec (CVE-2021-4034)
Date: 01/25/2022
Exploit Author: Qualys Research Team
Tested on: ubuntu 20.04.1 LTS
CVE ID: CVE-2021-27928
```

## How to Exploit
Test Environment：

![img](img/env.png)

Step 1：build the exp(From https://github.com/berdav/CVE-2021-4034)

```
make
```

![img](img/build.png)

Step 2：run exploit and get a root shell

![img](img/root.png)

### Analysis Detail

https://blog.qualys.com/vulnerabilities-threat-research/2022/01/25/pwnkit-local-privilege-escalation-vulnerability-discovered-in-polkits-pkexec-cve-2021-4034

### Reference

https://github.com/berdav/CVE-2021-4034

https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt

### Disclosure Timeline

- 2021-11-18: Advisory sent to secalert@redhat.
- 2022-01-11: Advisory and patch sent to distros@openwall.
- 2022-01-25: Coordinated Release Date (5:00 PM UTC).

File Snapshot


 [4.0K]  /data/pocs/bf51e9949abc91ea6e8fa111bf9bc68eb49f58ae
├── [ 274]  cve-2021-4034.c
├── [4.0K]  img
│   ├── [161K]  build.png
│   ├── [167K]  env.png
│   └── [ 70K]  root.png
├── [ 400]  Makefile
├── [ 266]  pwnkit.c
└── [ 924]  README.md

1 directory, 7 files

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