The malicious changes were submitted by JiaT75, one of the two main xz Utils developers with years of contributions to the project.
“Given the activity over several weeks, the committer is either directly involved or there was some quite severe compromise of their system,” an official with distributor OpenWall wrote in an advisory. “Unfortunately the latter looks like the less likely explanation, given they communicated on various lists about the ‘fixes’” provided in recent updates. Those updates and fixes can be found here, here, here, and here.
On Thursday, someone using the developer’s name took to a developer site for Ubuntu to ask that the backdoored version 5.6.1 be incorporated into production versions because it fixed bugs that caused a tool known as Valgrind to malfunction.
“This could break build scripts and test pipelines that expect specific output from Valgrind in order to pass,” the person warned, from an account that was created the same day.
One of maintainers for Fedora said Friday that the same developer approached them in recent weeks to ask that Fedora 40, a beta release, incorporate one of the backdoored utility versions.
“We even worked with him to fix the valgrind issue (which it turns out now was caused by the backdoor he had added),” the Ubuntu maintainer said.
He has been part of the xz project for two years, adding all sorts of binary test files, and with this level of sophistication, we would be suspicious of even older versions of xz until proven otherwise.
That link doesn’t prove whatever you think it’s proving.
The open source ecosystem does not rely (exclusively) on project maintainers to ensure security. Security audits are also done by major enterprise-grade distribution providers like Red Hat Enterprise. There are other stakeholders in the community as well who have a vested interest in security, including users in military, government, finance, health care, and academic research, who will periodically audit open source code that they’re using.
When those organizations do their audits, they will typically report issues they find through appropriate channels which may include maintainers, distributors, and the MITRE Corporation, depending on the nature of the issue. Then remedial actions will be taken that depend on the details of the situation.
In the worst case scenario if an issue exists in an open source project that has an unresponsive or unhelpful maintainer (which I assume is what you were suggesting by providing that link), then there are several possible courses of action:
- Distribution providers will roll back the package to an earlier compatible version that doesn’t have the vulnerability if possible
- Someone will fork the project and patch the fix (if the license allows), and distribution providers will switch to the fork
- In the worst case scenario if neither of the above are possible, distribution providers will purge the vulnerable package from their distributions along with any packages that transitively depend on it (this is almost never necessary except as a short-term measure, and even then is extremely rare)
The point being, the ecosystem is NOT strictly relying on the cooperation of package maintainers to ensure security. It’s certainly helpful and makes everything go much smoother for everyone if they do cooperate, but the vulnerability can still be identified and remedied even if they don’t cooperate.
As for the original link, I think the correct takeaway from that is: If you have a vested or commercial interest in ensuring that the open source packages you use are secure from day zero, then you should really consider ways to support the open source projects you depend on, either through monetary contributions or through reviews and code contributions.
And if there’s something you don’t like about that arrangement, then please consider paying for licenses on closed-source software which will provide you with the very reassuring “security by sticking your head in the sand”, because absolutely no one outside the corporation has any opportunity to audit the security of the software that you’re using.
That link doesn’t prove whatever you think it’s proving.
That link strengthens my argument that we’re assuming because it’s open source that the code is less likely to have security issues because it’s easier to be audited, when in truth it really just depends on the maintainer to do the proper level of effort or not, since it’s volunteer work.
When someone suggested a level of effort to be put on code checked in to prevent security issues from happening, the maintainer pushed back, stating that they will decide what level of effort they’ll put in, because they’re doing the work on a volunteer basis.
And my rebuttal is three-fold:
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Security does not depend entirely on the maintainer, and there is recourse even in the worst case scenario of an uncooperative or malicious maintainer.
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The maintainer you quoted said he would be open to complying with requests if the requesters were willing to provide monetary support. You are intentionally misrepresenting their position.
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The alternative of closed source software doesn’t actually protect you from security issues, it just makes it impossible for any users to know if the software has been compromised. For all you know, a closed source software product could be using one of the hypothetical compromised open source software project that you’re so afraid of, and you would never actually know.
If you’re willing to pay a license for a private corporation’s closed source software so you get the pleasure of never being able to know your security posture, then why would you be unwilling to financially support open source developers so they have the resources they need to have the level of security that you’d like from them?
