OverlayFS — CVE-2021–3493 || Writeup || Tryhackme
📖 Introduction
What is OverlayFS.?
OverlayFS is a Linux kernel module that allows the system to combine several mount points into one, so that you can access all the files from each within one directory structure.
It’s often used by live USBs, or some other specialist applications. One use is having a read only root file system, and another partition “overlayed” with that to allow applications to write to a temporary file system.
More resources are included in the final task (Further reading) if you’d like to learn more about OverlayFS and this exploit.
I have a very rough overview of what OverlayFS is — — →
No Answer Needed
CVE-2021–3493 — OverlayFS Exploit
Credentials for SSH
Start the Attack box and and login into the SSH using the credentials given in the task.
Answer the questions below:
No Answer Required.
SSH into the machine with the credentials provided in the task text.
No Answer Rerquired
Grab the source code for the exploit from SSD-Disclosure here and save it as exploit.c on the target machine.
Go to the link provided and save the exploit as exploit.c using Vim editor or nano editor in the terminal.
Compile the exploit with gcc.
Compile the code using the command
Run your compiled exploit, and get root!
What’s the flag in /root/?
bash-4.4# id
bash-4.4# cd /root/
bash-4.4# cat flag.txt
Happy Hacking..!!
fathallah17/overlayfs-cve-2021-3493
