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Barny_Riches's avatar
Barny_Riches
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Jan 27, 2021

CVE-2021-3156 | SUDO Heap-based Buffer Overflow

Are any of the BIG-IP versions affected by the recent SUDO vulnerability announcement? I have checked our F5 estate and I don't believe that the SUDO package is installed or used, but I just want to be sure.

6 Replies

  • DMan's avatar
    DMan
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    F5s seems to be vulnerable, to confirm, see below:

     

    How can I test if I have vulnerable version?

    To test if a system is vulnerable or not, login to the system as a non-root user.

    Run command “sudoedit -s /”

    If the system is vulnerable, it will respond with an error that starts with “sudoedit:”

    If the system is patched, it will respond with an error that starts with “usage:”

    • Barny_Riches's avatar
      Barny_Riches
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      Thanks for the reply, that's interesting. My BIG-IP (15.1.04) instances return:

      sudoedit: command not found

      Running an rpm -qa query also doesn't show sudo being installed. Could sudo be installed on some versions and not others?

  • DMan's avatar
    DMan
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    Interesting - I have tried it on v14.1.x and 15.1.2 boxes and when i type the "sudoedit -s /" getting a sudoedit: error response back.

  • I have tried it on F5 v12.1.5.2

    testuser@F5v12-1-5-2:~$ sudoedit -s /
    sudoedit: /: not a regular file
    testuser@F5v12-1-5-2:~$ 

    Test on Linux vm before and after patch

    testuser@vm-not-patched:~$ sudoedit -s /
    sudoedit: /: not a regular file
    testuser@vm-not-patched:~$ 
     
    testuser@vm-patched:~$ sudoedit -s /
    usage: sudoedit [-AknS] [-r role] [-t type] [-C num] [-g group] [-h host] [-p prompt] [-T timeout] [-u user] file ...
    testuser@vm-patched:~$
  • I just opened a P2 case with F5 regarding this vulnerability. They responded saying BIG-IP devices are not affected and that F5 will have a public facing KB regarding the vulnerability in the next couple of days.