🖥️OverlayFS: CVE-2021-3493
Exploit a 2021 Kernel vulnerability in Ubuntu to become root almost instantly!
Room Attributes
Value
Subscription Required
False [Free]
Type
Walkthrough
Difficulty
Info
Tags
PrivEsc, Linux, Ubuntu, Kernel, CVE-2021-3493
Task 1 - What is OverlayFS?
I have a very rough overview of what OverlayFS is
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Task 2 - CVE-2021-3493 - OverlayFS Exploit
Deploy the machine with the Start Machine button in this task and wait up to 2 minutes for the VM to boot.
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SSH into the machine with the credentials provided in the task text.
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Grab the source code for the exploit from SSD-Disclosure here and save it as exploit.c on the target machine.
HINT: Perhaps the easiest way is copy/pasting the code into a text editor like Nano or Vim!
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Compile the exploit with gcc. If you're finding this difficult, a command is given in the hints.
HINT: gcc -o exploit exploit.c
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Run your compiled exploit, and get root! What's the flag in /root/?
Task 3 - Further reading
Hope you've enjoyed this short room.
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