openSUSE maintainers received notification of a supply chain attack against the “xz” compression tool and “liblzma5” library.

Background

Security Researcher Andres Freund reported to Debian that the xz / liblzma library had been backdoored.

This backdoor was introduced in the upstream github xz project with release 5.6.0 in February 2024.

Our rolling release distribution openSUSE Tumbleweed and openSUSE MicroOS included this version between March 7th and March 28th.

SUSE Linux Enterprise and Leap are built in isolation from openSUSE. Code, functionality and characteristics of Tumbleweed are not automatically introduced in SUSE Linux Enterprise and/or Leap. It has been established that the malicious file introduced into Tumbleweed is not present in SUSE Linux Enterprise and/or Leap.

Impact

Current research indicates that the backdoor is active in the SSH Daemon, allowing malicious actors to access systems where SSH is exposed to the internet.

As of March 29th reverse engineering of the backdoor is still ongoing.

Mitigations

openSUSE Maintainers have rolled back the version of xz on Tumbleweed on March 28th and have released a new Tumbleweed snapshot (20240328 or later) that was built from a safe backup.

The reversed version is versioned 5.6.1.revertto5.4 and can be queried with rpm -q liblzma5.

User recommendation

For our openSUSE Tumbleweed users where SSH is exposed to the internet we recommend installing fresh, as it’s unknown if the backdoor has been exploited. Due to the sophisticated nature of the backdoor an on-system detection of a breach is likely not possible. Also rotation of any credentials that could have been fetched from the system is highly recommended. Otherwise, simply update to openSUSE Tumbleweed 20240328 or later and reboot the system.

More Information about openSUSE:

  • @[email protected]
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    8 months ago

    It’s good that it didn’t get into Leap or Enterprise. Servers for businesses shouldn’t generally be using Tumbleweed.

    It sounds like to be really vulnerable a machine has to expose SSH to the internet. So if that’s correct then most typical home computers should be safe. Based on that assumption I’m not rushing to wipe and reinstall.

    • @[email protected]
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      348 months ago

      What scary is the maintainer that insert the backdoor has been main maintainer for xz for the last two years. Who know if they have other backdoors inserted in the last 2 years? Investigation is still ongoing so I expect more juicy revelations in the next few days.

    • @Lime66
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      28 months ago

      doesn’t pushing to github (and probably a selfhosted equivalent) require ssh to do without entering your password every single time?