Dirty Pipe - Linux Local Privilege Escalation

Similar to the “Dirty COW” exploit (CVE-2016-5195), this flaw abuses how the Kernel manages pages in pipes and impacts the latest versions of Linux. The vulnerability is unofficially rated at a critically severe score of 8.8, which is extremely high for a local vulnerability.

• Dirty Pipe (CVE-2022-0847) is a local privilege escalation vulnerability in the Linux kernel that could potentially allow an unprivileged user to do the following:
  • Modify/overwrite arbitrary read-only files like /etc/passwd.
  • Obtain an elevated shell.

Affected versions

• Linux kernel versions newer than 5.8 are affected.
• So far the vulnerability has been patched in the following Linux kernel versions:
  • 5.16.11
  • 5.15.25
  • 5.10.102
• You can learn more about the vulnerability here: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-0847

DirtyPipe Vulnerability Scanner

• If you are not sure if a target system is vulnerable, use this really cool bash script developed by @basharkey.
• DirtyPipe Checker: https://github.com/basharkey/CVE-2022-0847-dirty-pipe-checker

Compiling the exploit

• An automated compiler bash script has been provided to you to automate the compilation of both exploits.
• In order to compile the exploit succesfully, you will need to have GCC installed.

sudo apt-get install gcc

• After installing GCC, you can run the ‘compile.sh” script as follows:

chmod +x compile.sh

./compile.sh

Exploit-1 - Modifying/overwriting read only files

• This repo contains 2 exploits, the ‘exploit-1.c’ exploit can be used to modify or overwrite arbitrary read only files.
• This exploit is a proof of concept that was developed by Max Kellermann and has been modified to change the root password in the /etc/passwd file, consequently providing you with access to an elevated shell.

Running the exploit binary

• The exploit code has already been configured to replace the root password with the password “piped” and will take a backup of the /etc/passwd file under /tmp/passwd.bak. Furthermore, the exploit will also provide you with an elevated root shell and will restore the original passwd file when done.

./exploit-1

Exploit-2 - Hijacking SUID binaries

• This exploit can be used to inject and overwrite data in read-only SUID process memory that run as root.

Finding SUID binaries

find / -perm -4000 2>/dev/null

Running the exploit binary

./exploit-2 /usr/bin/sudo

Important Note

• I do not claim credit/ownership/disclosure of the vulnerability and all corresponding exploits hosted in this GitHub repo.
• All the credit goes to the awesome Max Kellerman, you can check out the official disclosure here: https://dirtypipe.cm4all.com/

Credits

• https://github.com/febinrev/dirtypipez-exploit
• https://github.com/basharkey/CVE-2022-0847-dirty-pipe-checker