CVE-2021-4034 PoC — polkit 缓冲区错误漏洞

Source

https://github.com/fnknda/CVE-2021-4034_POC

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

Proof Of Concept for the 2021's pkexec vulnerability CVE-2021-4034

Readme

# CVE-2021-4034 - Proof Of Concept

This *POC* exploits *GLib*'s `g_printerr` to leverage code execution through the injection of the `GCONV_PATH` environmental variable.

## Running the exploit

Make a tarball file of the exploit:

```bash
make tar
```

Then somehow transfer the generated tar to the target machine, compile, and run the vulnerability:

```bash
make
./poc
```

The exploit will try to execute a `/bin/sh` as root.

## Further reading

* [The blog post this exploit was based on](https://milot.io/dissecting-pkexec-cve-2021-4034-vulnerability/)
* [An article to better understand the theory behind the attack](https://blog.qualys.com/vulnerabilities-threat-research/2022/01/25/pwnkit-local-privilege-escalation-vulnerability-discovered-in-polkits-pkexec-cve-2021-4034)

File Snapshot


 [4.0K]  /data/pocs/23cef84578508bf73dfa5b5a3de2295bd30f6484
├── [4.0K]  GCONV_PATH=.
│   └── [   0]  modules
├── [ 233]  lib.c
├── [ 221]  Makefile
├── [4.0K]  modules
│   └── [  38]  gconv-modules
├── [ 234]  poc.c
└── [ 786]  README.md

2 directories, 6 files

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