It looks to be limited to Linux systems that are running certain patches. macOS and BSD seem unaffected?
Ubuntu 22.04 version:
dpkg -l |grep liblzma ii liblzma5:amd64 5.2.5-2ubuntu1 amd64 XZ-format compression library
Whew!
I am *not* a security researcher, nor a reverse engineer. There's lots of
stuff I have not analyzed and most of what I observed is purely from
observation rather than exhaustively analyzing the backdoor code.The systemd notification protocol could have been as simple as just writing a newline to a pipe, but instead you have to link to the libsystemd C library, so now security-critical daemons like openssh have additional dependencies like liblzma loaded into their address space (even if you don't use systemd as PID 1), increasing the risks of supply chain attacks. Thanks, systemd.
It is known to be in version 5.6.0 and 5.6.1, and the obfuscated code is found in the test directory.
Also super weird a contributor thought they could slip this in and not have it be noticed at some point. It may point to burning that person (aka, they go to jail) for whatever they achieved with this. (And whoever they are…)
Does that mean this affects RHEL and Fedora?
I worked in the software supply chain field and cannot resist feeling the entire point of that industry is to make companies pay for a security certificate so you can shift the blame onto someone else when things go wrong.
Makes you wonder what more competent actors can do.
He has been part of the xz project for 2 years, adding all sorts of binary test files, and to be honest with this level of sophistication I would be suspicious of even older versions of xz until proven otherwise.
https://github.com/tukaani-project/xz/commit/af071ef7702debe...
Would be interesting to see what's going on here; the person who did the releases has done previous releases too (are they affected?) And has commits going back to 2022 – relatively recent, but not that recent. Many are real commits with real changes, and they have commits on some related projects like libarchive. Seems like a lot of effort just to insert a backdoor.
Edit: anyone with access can add files to existing releases and it won't show that someone else added it (I just tested). However, the timestamp of the file will be to when you uploaded it, not that of the release. On xz all the timestamps of the files match with the timestamp of the release (usually the .tar.gz is a few minutes earlier, which makes sense). So looks like they were done by the same person who did the release. I suspected someone else might have added/altered the files briefly after the release before anyone noticed, but that doesn't seem to be the case.
- A very recent version of liblzma5 - 5.6.0 or 5.6.1. This was added in the last month or so. If you're not on a rolling release distro, your version is probably older.
- A debian or RPM based distro of Linux on x86_64. In an apparent attempt to make reverse engineering harder, it does not seem to apply when built outside of deb or rpm packaging. It is also specific to Linux.
- Running OpenSSH sshd from systemd. OpenSSH as patched by some distros only pulls in libsystemd for logging functionality, which pulls in the compromised liblzma5.
Debian testing already has a version called '5.6.1+really5.4.5-1' that is really an older version 5.4, repackaged with a newer version to convince apt that it is in fact an upgrade.
It is possible there are other flaws or backdoors in liblzma5, though.
https://github.com/tukaani-project/xz/commit/af071ef7702debe...
Not sure what to make of this.
$ xz --version
xz (XZ Utils) 5.6.1
liblzma 5.6.1
https://github.com/tukaani-project/xz/commit/af071ef7702debe...
Removes instructions about details relevant to security reports. Heh, nice one.
My understanding is that right now it's pretty much a name and shame of people who most of the time aren't even real "people" but hostile agents either working for governments or criminal groups ( or both )
Getting punched in the face is actually a necessary human condition for a healthy civilization.
> If you discover a security vulnerability in this project please report it privately. *Do not disclose it as a public issue.* This gives us time to work with you to fix the issue before public exposure, reducing the chance that the exploit will be used before a patch is released.
Reading that in a different light, it says give me time to adjust my exploits and capitalize on any targets. Makes me wonder what other vulns might exist in the author's other projects.
About a week ago I received the first PR on that repo, to upgrade to 5.6.1. I thought it was odd to get such a random PR...it's not the same GitHub account as upstream though.
edit to add: Arch Linux' entire package system used to run on .tar.xz binaries (they switched to Zstd a few years ago [0]).
[0] https://news.ycombinator.com/item?id=19478171 ("Arch Linux propose changing compression method from xz to zstd (archlinux.org)")
> Note: GitHub automatically includes two archives Source code (zip) and Source code (tar.gz) in the releases. These archives cannot be disabled and should be ignored.
The author was thinking ahead! Latest commit hash for this repo: 8a3b5f28d00ebc2c1619c87a8c8975718f12e271
It is too easy to hide things in testdata.
Can we start including a blacklist of emails and names of contributors (with reasons/links to discussions)?
I can't track them and I don't want them in my projects.
Might not be very helpful as it is easy to create new identities, but I see no reason to make it easier for them. Also, I might approach differently someone with lots of contributions to known projects than a new account, so it still helps.
But luckily there was some serendipity: "I accidentally found a security issue while benchmarking postgres changes." https://mastodon.social/@AndresFreundTec/112180083704606941
I literally can't make heads or tails of the risk here. All I see is the very alarming and scary words "backdoor" and "ssh server" in the same sentence.
If I am keeping stuff up to date, is there anything at all to worry about?
My server runs arch w/ a LTS kernel (which sounds dumb on the surface, but was by far the easiest way to do ZFS on Linux that wasn't Ubuntu) and it seems that since I don't have SSH exposed to the outside internet for good reason, and my understanding is Arch never patched shhd to begin with that I and most people who would be in similar situations to me are unaffected.
Still insane that this happened to begin with, and I feel bad for the Archlinux maintainers who are now going to feel more pressure to try to catch things like this.
https://lore.kernel.org/lkml/20240320183846.19475-2-lasse.co...
https://web.archive.org/web/20240329182300/https://www.openw...
I'm recalling bad memories of the Juniper backdoor years ago.
Whoever did this, was playing the long game. As the top post pointed out, there was an effort to get this into Fedora.... which eventually makes its way into RHEL (read: high value targets). This was not for short term payoffs by some rogue developer trying to mine crypto or other such nonsense. What you are seeing here is the planting of seeds for something months or a year down the road.
{0}[calvinow@mozart ~] dpkg-query -W liblzma5
liblzma5:amd64 5.6.0-0.2
{0}[calvinow@mozart ~] hexdump -ve '1/1 "%.2x"' /lib/x86_64-linux-gnu/liblzma.so.5 | grep -c f30f1efa554889f54c89ce5389fb81e7000000804883ec28488954241848894c2410
1
Abandonment and inaction, the actual developers of these tools are elsewhere, oblivious to this drama, trying to make living because most of the time you are not compensated nor any corporation cares about making things sustainable at all. This is the default status of everything your fancy cloud depends on underneath.
An attacker took over of the project slowly and stayed dormant until recently.
https://aws.amazon.com/security/security-bulletins/AWS-2024-...
That's devastating.
If you don't build your release packages from feeding "git ls-files" into tar, you are doing it wrong.
At the time I thought it was just rude, but maybe this is when it all started.
It's a known fact that China will "recruit" people to operate them. A quote:
> They talk to them, say my friend, I see you like our special menu. Are you from China? Are you here on a VISA? Do you have family back there? Would you like your family to stay alive? Is your loyalty to this temporary employer or is your loyalty to your motherland? You know, a whole bunch of stuff like that. That’s how Chinese intelligence operations acts...
This just gives feelings of less "compromised account" and more "Your account is now our account"
Let me guess, autotools? I want to rage shit post but I guess I'll wait for confirmation first.
EDIT: YUP, AT LEAST PARTIALLY. Fucking god damn autotools.
I hope Lasse Collin still has control of his accounts, though the CC on the kernel mailing list looks kind of suspicious to me.
Randomly picked https://github.com/Neustradamus and looked at all their contributions.
Interestingly enough, they got Microsoft to upgrade ([0],[1]) `vcpkg` to liblzma 5.6.0 3 weeks ago.
I wonder what amount of scrutiny all the accounts that proposed the upgrade should be put under.
[0] https://github.com/search?q=liblzma+5.6.0&type=pullrequests
WHOWAS jiatan provided me the following information:
jiatan ~jiatan 185.128.24.163 * :Jia Tan jiatan 185.128.24.163 :actually using host jiatan jiatan :was logged in as jiatan tungsten.libera.chat :Fri Mar 14:47:40 2024
WHOIS yields nothing, the user is not present on the network at the moment.
Given that 185.128.24.163 is covered with a range-block on the English Wikipedia, it appears this is a proxy.
Are they somehow in the clear unless we can show they actively exploited it?
You only get this kind of humility when you're working with absolute wizards on a consistent basis.
I really don't think some random guy wants to weaken ssh just to extract some petty ransomware cash from a couple targets.
it wasn't the apparently newly-created identity "Hans Jansen" just asking for a new version to be uploaded, it was "Hans Jansen" providing a new version to be uploaded as a non-maintainer-upload - Debian-speak for "the maintainer is AWOL, someone else is uploading their package". if "Hans Jansen" is another attacker then they did this cleverly, providing the new - compromised - upstream tarballs in an innocent-looking way and avoiding anyone examining the upstream diff.
Who else would have run a PostgreSQL performance benchmark and discover a major security issue in the process?
It's something always in the back of our minds as developers using public libraries, but when something like this happens, non-developers that hear about it start to associate it with the rest of the open-source community.
It's essentially a terrorist attack on developer experience. Thankfully, management doesn't follow the same approach as the TSA.
The known unknowns can be better than the unknown unknowns.
Here[0] is a very simple example, that shows how easy such supply chain attacks are in Rust; and lets not forget that there was a very large python attack just a few days ago[1].
[0] - https://github.com/c-skills/rust1
[1] - https://checkmarx.com/blog/over-170k-users-affected-by-attac...
Searching DDG for "jiat0218" I came across a blog post which I found weird. Seems to be dated: 2006-05-03
Blog post: "Kuso拍賣．有靈氣的筷子 - 闕小豪" <https://char.tw/blog/post/24397301>
Internet Archive link: <https://web.archive.org/web/20240329182713/https://char.tw/b...>
The contents of the page when translated seems to be about jiat0218 auctioning a pair of spiritual chopsticks as a prank.
The blog entry is basically a QA between jiat0218 and various other people about these chopsticks.
If Jia Tan does turn out to be a compromised maintainer working for a state actor then some of the content on the blog page can be viewed in a more sinister way (i.e. spycraft / hacks for sale etc.).
Example question 38:
Question 38
accounta066 (3): Are these chopsticks really that good? I kind of want to buy
them! But I recently sent money for online shopping but didn’t receive anything.
It’s very risky; currently jiat0218 you don’t have any reviews, you can
interview me. Do you want to hand it over?! … A sincere buyer will keep it.
Reply to
jiat0218 (4): First of all, I would like to express my condolences to you for
your unfortunate experience! What can I say about this kind of thing...My little
sister has always been trustworthy. What’s more, this is a pair of spiritual
chopsticks, so I hope to have a good one. It’s the beginning! As you can see,
my little sister is very careful and takes her time when answering your
questions. Except for the two messages that were accidentally deleted by her,
she always answers your questions. If this still doesn’t reassure you, then I
can only say that I still have room to work hard. You are still welcome
to bid... ^_^
Using the build system (and potentially the compiler) to insert malicious backdoors is far from a new idea, and I don't see why this example would the only case.
Xz: Disable ifunc to fix Issue 60259 - https://news.ycombinator.com/item?id=39869718
FAQ on the xz-utils backdoor - https://news.ycombinator.com/item?id=39869068
Everything I Know About the XZ Backdoor - https://news.ycombinator.com/item?id=39868673
zero definition of what that means...
egos of people who just like to say cool words they don't understand
lol
this comment will probably get deleted, but let the action of this comment being deleted stand that in 2024 we're all allowed to use big words with no definition of what they mean -> bad
state actor? who? what motive? what country? all comments involving "state actor" are very broad and strange... i would like people to stop using words that have no meaning, as it really takes away from the overall conversation of what is going on.
i mean you're seriously going to say "state actor playing the long game" to what end? the issue was resolved in 2 hours... this is stupid
I'm not *too* worried about OpenConnect given that we use `libxml2` only to read and parse uncompressed XML…
But I am wondering if there has been any statement from libxml2 devs (they're under the GNOME umbrella) about potential risks to libxml2 and its users.
Could have fooled me - impressive write-up!
I ran "brew upgrade" and that downgraded to version 5.4.6.
I got curious and decided to run 'ent' https://www.fourmilab.ch/random/ to see how likely the data in the bad stream was to be random. I used some python to split the data into 3 streams, since it's supposed to be the middle one that's "bad":
I used this regex to split in python, and wrote to "tmp":
re.split(b'\xfd7zXZ', x)
$ ent tmp2 # bad file payload
Entropy = 4.157806 bits per byte.
Optimum compression would reduce the size
of this 48 byte file by 48 percent.
Chi square distribution for 48 samples is 1114.67, and randomly
would exceed this value less than 0.01 percent of the times.
Arithmetic mean value of data bytes is 51.4167 (127.5 = random).
Monte Carlo value for Pi is 4.000000000 (error 27.32 percent).
Serial correlation coefficient is 0.258711 (totally uncorrelated = 0.0).
$ ent tmp3 # urandom
Entropy = 5.376629 bits per byte.
Optimum compression would reduce the size
of this 48 byte file by 32 percent.
Chi square distribution for 48 samples is 261.33, and randomly
would exceed this value 37.92 percent of the times.
Arithmetic mean value of data bytes is 127.8125 (127.5 = random).
Monte Carlo value for Pi is 3.500000000 (error 11.41 percent).
Serial correlation coefficient is -0.067038 (totally uncorrelated = 0.0).
https://github.com/tukaani-project/xz vs https://github.com/JiaT75
Definitely looking like they were most likely some sort of state actor. This is very well done and all in plain sight. It's reassuring that it was discovered but given a simple audit of the release build artifacts would have raised alarms, how prevalent is this behavior in other projects? Terrifying stuff.
I agree with the lzip guy
This would thwart brute force attacks, but not be a significant cost for users. If you could attach your login to the crypto account it would mean the account would have to be funded to allow the attempt. The token wouldn't store passwords it would just be a gatekeeper to the login attempt.
The fees would be paid to the service providers as mining fees.
E.g. foo@bar.com needs a password and a token provided from a designated crypto address to gain access to the service.
I find it incredibly ironic that a “version control” site gives no assurance of reproducible builds (nor reproducible source!!)
The real villain is not the perpetrator, it is Microsoft, and it is all of us.
5.4.5 can be compromised
nice
if [ "$path" == "" ]
should be
if [ "$path" = "" ]
``` #!/bin/bash
# Get list of all running Docker containers containers=$(docker ps --format "{{.Names}}")
# Loop through each container for container in $containers; do # Get container image image=$(docker inspect --format='{{.Config.Image}}' "$container")
# Execute xz --version inside the container
version=$(docker exec "$container" xz --version)
# Write container name, image, and command output to a text file
echo "Container: $container" >> docker_container_versions.txt
echo "Image: $image" >> docker_container_versions.txt
echo "xz Version:" >> docker_container_versions.txt
echo "$version" >> docker_container_versions.txt
echo "" >> docker_container_versions.txt
echo "Output written to docker_container_versions.txt" ```
A few interesting bits that I haven't fully fleshed out. TLDR: Some people have been throwing around that Jia is from “China,” but it seems also quite possible that Jia is from somewhere in Eastern Europe pretending to be from China. In addition, Lasse Collin and Hans Jansen are from the same EET time zone.
The following analysis was conducted on JiaT75’s (https://github.com/JiaT75?tab=overview&from=2021-12-01&to=20...) commits to the XZ repository, and their time stamps.
Observation 1: Time zone basic analysis
Here is the data on Jia’s time zone and the number of times he was recorded in that time zone: 3: + 0200 (in winter: February and November) 6: +0300 (in summer: in Jun, Jul, early October) 440: +0800
1. The +800 is likely CST. China (or Indonesia or Philippines), given that Australia does daylight savings time and almost no one lives in Siberia and the Gobi dessert. 2. The +0200/+0300, if we are assuming that this is one location, is likely on EET (Finland, Estonia, Latvia, Lithuania, Ukraine, Moldavia, Romania, Bulgaria, Greece, Turkey). This is because we see a switch from +300 in the winter (past the last weekend of October) and +200 in the summer (past the last Sunday in March). 1. Incidentally, this seems to be the same time zone as Lasse Collin and Hans Jansen…
Observation 2: Time zone inconsistencies
Let’s analyze the few times where Jia was recorded in a non +800 time zone. Here, we notice that there are some situations where Jia switches between +800 and +300/+200 in a seemingly implausible time. Indicating that perhaps he is not actually in +800 CST time, as his profile would like us to believe.
Jia Tan Tue, 27 Jun 2023 23:38:32 +0800 —> 23:38 + 8 = 7:30 (+ 1) Jia Tan Tue, 27 Jun 2023 17:27:09 +0300 —> 17:27 + 3 = 20:30 —> about a 9 hour difference, but a flight from China to anywhere in Eastern Europe is at a min 10 hours
Jia Tan Thu, 5 May 2022 20:53:42 +0800 Jia Tan Sat, 19 Nov 2022 23:18:04 +0800 Jia Tan Mon, 7 Nov 2022 16:24:14 +0200 Jia Tan Sun, 23 Oct 2022 21:01:08 +0800 Jia Tan Thu, 6 Oct 2022 21:53:09 +0300 —> 21:53 + 3 = 1:00 (+1) Jia Tan Thu, 6 Oct 2022 17:00:38 +0800 —> 17:00 + 8 = 1:00 (+1) Jia Tan Wed, 5 Oct 2022 23:54:12 +0800 Jia Tan Wed, 5 Oct 2022 20:57:16 +0800 —> again, given the flight time, this is even more impossible
Jia Tan Fri, 2 Sep 2022 20:18:55 +0800 Jia Tan Thu, 8 Sep 2022 15:07:00 +0300 Jia Tan Mon, 25 Jul 2022 18:30:05 +0300 Jia Tan Mon, 25 Jul 2022 18:20:01 +0300 Jia Tan Fri, 1 Jul 2022 21:19:26 +0800 Jia Tan Thu, 16 Jun 2022 17:32:19 +0300 Jia Tan Mon, 13 Jun 2022 20:27:03 +0800 —> the ordering of these time stamps and the switching back and forth between time zones looks strange.
Jia Tan Thu, 15 Feb 2024 22:26:43 +0800 Jia Tan Thu, 15 Feb 2024 01:53:40 +0800 Jia Tan Mon, 12 Feb 2024 17:09:10 +0200 Jia Tan Mon, 12 Feb 2024 17:09:10 +0200 Jia Tan Tue, 13 Feb 2024 22:38:58 +0800 —> this travel time is possible, but the duration of stay is unlikely
Observation 3: Strange record of time stamps
It seems that from the commits, often the time stamps are out of order. I am not sure what would cause this other than some tampering.
Observation 4: Bank holiday inconsistencies
We notice that Jia’s work schedule and holidays seems to align much better with an Eastern European than a Chinese person.
Disclaimer: I am not an expert in Chinese holidays, so this very well could be inaccurate. I am referencing this list of bank holidays:(https://www.bankofchina.co.id/en-id/service/information/late...)
Chinese bank holidays (just looking at 2023): - Working on 2023, 29 September: Mid Autumn Festival - Working on 2023, 05 April: Tomb Sweeping Day - Working on 2023, 26, 22, 23, 24, 26, 27 Jan: Lunar New Year
Eastern European holidays: - Never working on Dec 25: Christmas (for many EET countries) - Never working Dec 31 or Jan 1: New Years
Observation 5: Little weekend work —> salary job?
The most common working days for Jia were Tue (86), Wed (85), Thu (89), and Fri (79). If we adjust his time zone to EET, then that means he is usually working 9 am to 6 pm. This makes much more sense than someone working at midnight and 1 am on a Tuesday night.
These times also line up well with Hans Jansen and Lasse Collin.
I think it is more likely that Jia does this as part of his work… somewhere in Eastern Europe. Likely working with, or in fact being one and the same as, Hans Jansen and Lasse Collin.
These are my notes on time stamps/zones. There are a few interesting bits that I haven't fully fleshed out.
The following analysis was conducted on JiaT75’s (https://github.com/JiaT75?tab=overview&from=2021-12-01&to=20...) commits to the XZ repository, and their time stamps.
Observation 1: Time zone basic analysis
Here is the data on Jia’s time zone and the number of times he was recorded in that time zone:
3: + 0200 (in winter: February and November)
6: +0300 (in summer: in Jun, Jul, early October)
440: +0800
1. The +800 is likely CST. China (or Indonesia or Philippines), given that Australia does daylight savings time and almost no one lives in Siberia and the Gobi dessert.
2. The +0200/+0300, if we are assuming that this is one location, is likely on EET (Finland, Estonia, Latvia, Lithuania, Ukraine, Moldavia, Romania, Bulgaria, Greece, Turkey). This is because we see a switch from +300 in the winter (past the last weekend of October) and +200 in the summer (past the last Sunday in March).
Incidentally, this seems to be the same time zone as Lasse Collin and Hans Jansen…
Observation 2: Time zone inconsistencies
Let’s analyze the few times where Jia was recorded in a non +800 time zone. Here, we notice that there are some situations where Jia switches between +800 and +300/+200 in a seemingly implausible time. Indicating that perhaps he is not actually in +800 CST time, as his profile would like us to believe.
Jia Tan Tue, 27 Jun 2023 23:38:32 +0800 —> 23:38 + 8 = 7:30 (+ 1) Jia Tan Tue, 27 Jun 2023 17:27:09 +0300 —> 17:27 + 3 = 20:30 —> about a 9 hour difference, but flight from China to anywhere in Eastern Europe is at a min 10 hours
Jia Tan Thu, 5 May 2022 20:53:42 +0800
Jia Tan Sat, 19 Nov 2022 23:18:04 +0800
Jia Tan Mon, 7 Nov 2022 16:24:14 +0200
Jia Tan Sun, 23 Oct 2022 21:01:08 +0800
Jia Tan Thu, 6 Oct 2022 21:53:09 +0300 —> 21:53 + 3 = 1:00 (+1)
Jia Tan Thu, 6 Oct 2022 17:00:38 +0800 —> 17:00 + 8 = 1:00 (+1)
Jia Tan Wed, 5 Oct 2022 23:54:12 +0800
Jia Tan Wed, 5 Oct 2022 20:57:16 +0800
—> again, given the flight time, this is even more impossible
Jia Tan Fri, 2 Sep 2022 20:18:55 +0800
Jia Tan Thu, 8 Sep 2022 15:07:00 +0300
Jia Tan Mon, 25 Jul 2022 18:30:05 +0300
Jia Tan Mon, 25 Jul 2022 18:20:01 +0300
Jia Tan Fri, 1 Jul 2022 21:19:26 +0800
Jia Tan Thu, 16 Jun 2022 17:32:19 +0300
Jia Tan Mon, 13 Jun 2022 20:27:03 +0800
—> the ordering of these time stamps, and the switching back and forth looks strange.
Jia Tan Thu, 15 Feb 2024 22:26:43 +0800
Jia Tan Thu, 15 Feb 2024 01:53:40 +0800
Jia Tan Mon, 12 Feb 2024 17:09:10 +0200
Jia Tan Mon, 12 Feb 2024 17:09:10 +0200
Jia Tan Tue, 13 Feb 2024 22:38:58 +0800
—> this travel time is possible, but the duration of stay is unlikely
Observation 3: Strange record of time stamps It seems that from the commits, often the time stamps are out of order. I am not sure what would cause this other than some tampering.
Observation 4: Bank holiday inconsistencies
We notice that Jia’s work schedule and holidays seem to align much better with an Eastern European than a Chinese person.
Disclaimer: I am not an expert in Chinese holidays, so this very well could be inaccurate. I am referencing this list of bak holidays:(https://www.bankofchina.co.id/en-id/service/information/late...)
Chinese bank holidays (just looking at 2023):
- Working on 2023, 29 September: Mid Autumn Festival
- Working on 2023, 05 April: Tomb Sweeping Day
- Working on 2023, 26, 22, 23, 24, 26, 27 Jan: Lunar New Year
Eastern European holidays:
- Never working on Dec 25: Christmas (for many EET countries)
- Never working Dec 31 or Jan 1: New Years
Observation 5: No weekend work —> salary job?
The most common working days for Jia was Tue (86), Wed (85), Thu (89), and Fri (79). If we adjust his time zone to be EET, then that means he is usually working 9 am to 6 pm. This makes much more sense than someone working at midnight and 1 am on a Tuesday night.
These times also line up well with Hans Jansen and Lasse Collin.
I think it is more likely that Jia does this as part of his work… somewhere in Eastern Europe. Likely working with, or in fact being one and the same as, Hans Jansen and Lasse Collin.
https://git.tukaani.org/?p=xz.git;a=commitdiff;h=4323bc3e0c1...
It's written in Pascal, and the only (semi-)documented way to build it yourself is to use a graphical IDE, and pull in pre-compiled library binaries (stored in the git repo of a dependency which afaict Pack is the only dependent of - appears to be maintained by the same pseudonymous author but from a different account).
I've opened an issue[2] outlining my concerns. I'm certainly not accusing them of having backdoored binaries, but if I was setting up a project to be deliberately backdoorable, it'd look a lot like this.
[0] https://pack.ac/
Should we start doing background checks on all committers to such critical IT infrastructure?
Obviously a bad actor will make use of these conditions and the assumption of good will.
We need automated tooling to vet for stuff like this. And maybe migrate away from C/C++ while we are at it because they don't make such scanning easy at all.
"I haven't lost interest but my ability to care has been fairly limited mostly due to longterm mental health issues but also due to some other things. Recently I've worked off-list a bit with Jia Tan on XZ Utils and perhaps he will have a bigger role in the future, we'll see.
It's also good to keep in mind that this is an unpaid hobby project. "
Github (Microsoft) are in a unique position to figure out if his account is hacked or not, and find a way to reach him. I hope they reach out and offer him some proper support! Economic support (if that's needed), or just help clearing his name.
This is another tale of how we are building multi trillion dollar industries on the back of unpaid volunteers. It's not github 'job', and many other organisations have benefited even more from Lasses work, but they are in a unique position, and would be literally pocket change for them.
1:https://www.mail-archive.com/xz-devel@tukaani.org/msg00567.h...
The offending tarball for v5.6.1 is easier to find, an example being.[2]
m4/.gitignore was updated 2 weeks ago to hide build-to-host.m4 that is only present in the release tarball and is used to inject the backdoor at build time.[3]
[1] https://git.phial.org/d6/xz-analysis-mirror
[2] https://mirrors.xtom.ee/gentoo/distfiles/9f/xz-5.6.1.tar.gz
[3] https://git.phial.org/d6/xz-analysis-mirror/commit/4323bc3e0...
Why? Well, consider this, to "contribute" to a proprietary project you need to get hired by a company, go through their he. Also they have to be hiring in the right team etc. Your operative has to be in a different country, needs a CV that checks out, passports/ids are checked etc.
But to contribute to an OS project? You just need an email address. Your operative sends good contributions until they build trust, then they start introducing backdoors in the part of the code "no one, but them understands".
The cost of such attack is a lot lower for a state actor so we have to assume every single OS project that has a potential to get back doored had many attempts of doing so. (proprietary software too, but as mentioned, this is much more expensive)
So what is the solution? IDK, but enforcing certain "understandability" requirements can be a part of it.
For every one of these we spot, assume there are two we have not.
Github just disabled the repo : https://github.com/tukaani-project/xz
Do someone have an up to date fork to see the project history ?
https://github.com/emirkmo/xz-backdoor-github
For those who want to see the GitHub events (commits, comments, pull_requets, diffs, etc.)
IMHO all maintainers of the backdooored projects anyhow related to accepting the malicious changes should be considered as accomplices and boycotted. We don't need evidence of their liability, it is they who need to maintain their reputation. We are just free to take our decisions based on their reputation. Even if they were hacked themselves, it is not our problem, it is their problem. Our problem is to keep ourselves safe. It may feel "unjust" to ruin reputation of a person based on the fact he may be cheated or hacked… But if a person can be cheated or hacked, why should he/she have such a good reputation as everyone else?! So, it makes a lot of sense to just exclude and replace everyone, for whome there exists evidence of comprometation, no matter due to unconcern or malice. But FOSS is a doocracy serving products at dumpling prices ($0, free of charge), and for majority backdoored software is completely acceptable given that they get them free of charge. And powerful actors who can afford to pay for software will just hire devs to develop their private versions, while allowing the public to pay $0 for their free versions and use the backdoors placed into them themselves. In other words a complete market failure.
I think that 1. xz project must be shut down completely. I mean projects should stop using it as a dependency, exclude from distros, boycott it. LZMA algo was developed by Igor Pavlov in 7z project, but somehow it has happenned that liblzma was developed and maintained by unrelated folks. liblzma should be developed as a part of 7z project taking no code other than the trivial one for API compatibility adapter from xz. 2. Projects created by compromised authkrs should be boycotted. 3. Other projects touched by the compromised devs/maintainers should be audited. 4. All the projects using autotools should be audited and must replace autotools with cmake/meson. Autotools is a piece of shit, completely uncomprehensible. There is no surprise it was used to hude a backdoor - according to my experience in FOSS noone likes to touch its scripts anyhow. 5. No project should be built from releases. Project should be built from git directly. Implementing full support of SHA256 in git and git forges (GitHub, GitLab, Codeberg, sr.ht) should be accelerated to mitigate attacks using collisions to replace approved commits (I guess the randomness can be concealed from reviewer's eye in binary resource files, like pictures).
Turns out burned out maintainers are a great attack vector and if you are willing to play the long game you can ingratiate yourself with the community with your seemingly innocuous contributions.
A malware code injection in upstream xz-tools is a vector for remote exploitation of the ssh daemon due to a dependency on systemd for notifications and due to systemd's call to dlopen() liblzma library (CVE-2024-3094). The resulting build interferes with authentication in sshd via systemd.
Also, some info here: https://tukaani.org/xz-backdoor/
[0] https://github.com/python/cpython/blob/main/PCbuild/get_exte...
The perpetrator did most GitHub actions between 10 and 18 UTC, which sort of rules out US based, unless the messages were scheduled. Consistent with Europe to Asia.
See clickhouse for data: https://play.clickhouse.com/play?user=play#U0VMRUNUICogRlJPT...
I am taking the initiative to gather more information regarding the possible precursors and perpetrators of the backdoor.
The purpose of this commentary is focused on open source information (OSINT).
I am not a judge of anyone or any action that may occur, the objective of this comment is to help through accurate and quick information to help the core developers of the affected packages and consequently the Linux kernel (which may have been indirectly or directly affected) take action necessary in relation to the fact that occurred.
NOTE: This comment will always have "edit" so always review it for information.
Information I have so far.
Summary: 1. GitHub Account Suspension: - The accounts of @JiaT75 and @Larhzu were suspended by GitHub. - All Tukaani repositories, including downloads, were disabled. - Investigate the cause of the account suspensions and whether there is any correlation with suspicious activities.
2. Possible Backdoor in xz/liblzma: - There are concerns about the presence of a backdoor in xz/liblzma. - Investigate whether there is evidence of compromise in the source code and recent updates. - Examine potential impacts, especially if the software is used in critical systems.
3. Updates and Patches in Packages: - Note recent updates in packages such as MinGW w64, pacman-static, Alpine, and OpenSUSE. - Review changelogs to understand if these updates are related to security fixes.
4. Jia's Activities on Platforms and Projects: - Investigate Jia's contributions to different projects and platforms, such as Arch Linux, Alpine Linux, and OpenSUSE. - Check for correlations between Jia's activities and reported security issues.
5. Libera Registration Information: - Analyze Jia's registration details on Libera to determine the timeline of their online activities. - Consider correlating this information with other online activities of Jia.
6. VPN Usage: - Confirm Jia's use of VPN and assess its impact on security investigations. - Explore possible reasons for using a VPN and how it may affect the identification and tracking of online activities.
Links related to user JiaT75 [xz] Remove JiaT75 as a contact, determine correct contacts #11760 - Google/oss-fuzz https://github.com/google/oss-fuzz/issues/11760
Tuktest index hash #7 - tukaani-project/xz/pull/7 https://web.archive.org/web/20240329230522/https://github.co...
So much damage is caused just by adding a single maintainer to a project - imagine how much power you would have to wield the remote execution systems put in place by naive developers for "automatic updates".
All it takes is a single malicious maintainer given access to the new version update of some popular user software, and they have a new botnet of thousands of devices at their disposal. Better yet, after the backdoor installation, they can just release the real update and cover their tracks forever.
Automatic updates are like running web applications, but without any sandboxing or protection usually implemented by the browser.
It was probably a tactic to give a reason to upgrade. It's not always a fault for those who did or tried to do.
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