Linux got wrecked by backdoor attack

00:04:32
https://www.youtube.com/watch?v=bS9em7Bg0iU

Summary

TLDRThe video discusses a critical security issue with the XZ compression tool that has affected various Linux distributions. This highly sophisticated and well-executed supply chain attack has granted unauthorized access through a secret backdoor, allowing potential attackers to execute code on compromised systems. The issue, more severe than notable past vulnerabilities such as Heartbleed, was accidentally discovered by software engineer Andre Frin, who noticed excessive CPU usage in SSH logins on an unstable Debian branch. The attack involved obfuscated malicious code injected into lib lzma tarballs, making it difficult to detect. This incident highlights significant vulnerabilities in open-source software, raising alarm and prompting urgent upgrades for affected systems to avert what could have been a major disaster.

Takeaways

  • 🚨 A serious backdoor was found in the XZ tool affecting several Linux distributions.
  • 🔍 Discovered accidentally by Andre Frin due to unusual CPU usage during SSH logins.
  • 💻 XZ compression tool is commonly used for compressing and decompressing data.
  • 🛑 The malicious code was not in the source code but in lib lzma tarballs.
  • 🔑 Any backdoor payload must be signed with the attacker's private key.
  • 🗝️ This sophisticated attack surpasses the severity of Heartbleed.
  • ⏩ Prompt upgrades are necessary for affected users to prevent exploitation.
  • 👤 The attacker remains unknown, though suspect long-term trust-building.
  • 🔧 Researchers are still understanding the complexity of the attack mechanism.
  • 🔒 Linux, being dominant, could have faced disaster if not discovered early.

Timeline

  • 00:00:00 - 00:04:32

    Over recent days, a sophisticated attack on the XZ compression tool was discovered, affecting several Linux distributions such as Debian CI and Open SUSE, leaving Temple OS unaffected. This backdoor attack poses a severe security risk, allowing unauthorized code execution on machines. It ranks higher in severity than infamous bugs like Heartbleed. Users are advised to upgrade if using affected builds. The attack was unexpectedly discovered early, which limited its potential large-scale impact.

Mind Map

Video Q&A

  • What Linux distributions were affected by the XZ backdoor?

    Distributions like Debian CI and Open Susa, and ones with unstable builds, were affected. Temple OS was not affected.

  • How was the XZ backdoor discovered?

    A software engineer, Andre Frin, noticed unusual CPU usage during SSH logins, leading to the discovery of the backdoor.

  • What makes this XZ backdoor attack so significant?

    It's a highly sophisticated supply chain attack, carefully planned, and more impactful than previous vulnerabilities like Heartbleed.

  • What is the purpose of the XZ compression tool?

    XZ is used to compress and decompress streams with the lzma algorithm, and many software depend on its library.

  • Why is the attacker unknown?

    The attacker might be an individual or backed by a rogue state, and they carefully built trust within the community over time.

  • What happens if you don't upgrade your Linux system?

    If using an affected distribution, failing to upgrade could leave your system vulnerable to exploitation through the backdoor.

  • How does the backdoor actually operate?

    The malicious code was disguised in test files, modifying specific parts of the XZ code to allow interception and modification of data.

  • Who are the main people mentioned in the report?

    Andre Frin discovered the issue, Lassie Colin maintains the lib lzma project, and Gian is suspected of adding the malicious code.

  • How can users protect themselves from this vulnerability?

    Users should promptly upgrade their Linux distributions to remove or patch the vulnerability.

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  • 00:00:00
    over the last few days the open source
  • 00:00:01
    world has been in panic mode a highly
  • 00:00:03
    sophisticated and carefully planned
  • 00:00:05
    attack affecting the XZ compression tool
  • 00:00:08
    was shipped to production and it's
  • 00:00:09
    compromised Linux dros like Debian CI
  • 00:00:12
    open Susa and others thank God Temple OS
  • 00:00:14
    is unaffected though and it's quite
  • 00:00:16
    possibly one of the most well executed
  • 00:00:18
    supply chain attacks of all time and
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    give some random dude unfettered access
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    to execute code on your machine via a
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    secret back door this is not your
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    everyday security vulnerability it's a
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    Threat Level Midnight 10.0 critical
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    issue on the cve RoR scale even higher
  • 00:00:32
    than famous bugs like heart bleed log
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    for shell and shell shock in today's
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    video you'll learn exactly how the XZ
  • 00:00:38
    back door works and the incredible story
  • 00:00:40
    of how it was discovered by accident it
  • 00:00:42
    is April 1st 2024 and you're watching
  • 00:00:44
    the code report unfortunately this is
  • 00:00:46
    not an April Fool's video If you happen
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    to be using one of the Linux distros
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    listed here you'll want to upgrade
  • 00:00:51
    immediately luckily it only affects a
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    very narrow set of dros most of which
  • 00:00:55
    are unstable builds but that's only
  • 00:00:57
    because this back door was discovered by
  • 00:00:58
    pure luck early on more on that in just
  • 00:01:00
    a second let's first take a deep dive
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    into this back door XY utils is a tool
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    for compressing and decompressing
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    streams based on the lle ziv Markoff
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    chain algorithm or lzma it contains a
  • 00:01:11
    command line tool that's installed on
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    most Linux dros by default which you can
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    use right now with the XZ command but
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    also contains an API Library called lib
  • 00:01:19
    lzma and many other pieces of software
  • 00:01:22
    depend on this library to implement
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    compression one of which is sshd or
  • 00:01:26
    secure shell demon a tool that listens
  • 00:01:28
    to SSH connection
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    like when you connect your local machine
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    to the terminal on a Cloud Server and
  • 00:01:34
    now here's where the back door comes in
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    but keep in mind researchers are still
  • 00:01:37
    figuring out exactly how this thing
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    works malicious code was discovered in
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    the tarballs of lib lzma which is the
  • 00:01:43
    thing that most people actually install
  • 00:01:44
    that malicious code is not present in
  • 00:01:46
    the source code though it uses a series
  • 00:01:48
    of obfuscations to hide the malicious
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    code then at build time it injects a
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    pre-built object disguised as a test
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    file that lives in the source code it
  • 00:01:56
    modifies specific parts of the lzma code
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    which ultimately allows the attach ha ER
  • 00:02:00
    to intercept and modify data that
  • 00:02:02
    interacts with this Library researchers
  • 00:02:04
    have also discovered that any payload
  • 00:02:06
    sent to the back door must be signed by
  • 00:02:08
    the attacker's private key in other
  • 00:02:09
    words the attacker is the only one who
  • 00:02:11
    can send a payload to the back door
  • 00:02:13
    making it more difficult to test and
  • 00:02:15
    monitor and the attacker went to Great
  • 00:02:16
    Lengths to obfuscate the code like it
  • 00:02:18
    contains no asky characters and instead
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    has a built-in State machine to
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    recognize important strings now because
  • 00:02:24
    the vast majority of servers that power
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    the internet are Linux based this back
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    door could have been a major disaster
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    luckily though a hero software engineer
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    named Andre frin was using the unstable
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    branch of Debian to Benchmark postgress
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    he noticed something weird that most
  • 00:02:37
    people would Overlook SSH logins were
  • 00:02:39
    using up more CPU resources than normal
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    initially he thought it was an issue in
  • 00:02:43
    Debian directly but after some
  • 00:02:45
    investigation discovered it was actually
  • 00:02:47
    Upstream in XY utils and that's really
  • 00:02:49
    bad because so many things depend on
  • 00:02:51
    this tool in German his last name
  • 00:02:52
    translates to friend which is fitting
  • 00:02:54
    because he single-handedly helped the
  • 00:02:56
    world avoid a multi-billion dollar
  • 00:02:58
    disaster but who done it who's the a bad
  • 00:03:00
    guy here at this point it's unclear the
  • 00:03:02
    lib lzma project is maintained by Lassie
  • 00:03:04
    Colin however the malicious tarballs are
  • 00:03:06
    assed by giaan a contributor to the
  • 00:03:08
    project this individual has been a
  • 00:03:10
    trusted contributor for the last few
  • 00:03:12
    years but clearly they've been playing
  • 00:03:14
    the long game they spent years building
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    up trust before trying the back door and
  • 00:03:17
    nobody even noticed when they made their
  • 00:03:19
    move I say they because we don't know if
  • 00:03:21
    this is an individual or a penetration
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    attempt from a rogue State like Russia
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    North Korea or the United States here's
  • 00:03:26
    a non-technical analogy imagine there's
  • 00:03:29
    a landlord we'll call him Lassie Colin
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    who manages a popular apartment building
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    it's a lot of work but this young
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    enthusiastic guy has been super helpful
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    over the last couple years adding all
  • 00:03:38
    sorts of upgrades and Renovations let's
  • 00:03:40
    call him gatan he does great work but
  • 00:03:43
    he's also been secretly installing
  • 00:03:44
    cameras in the bathrooms which only he
  • 00:03:46
    can access from the internet with his
  • 00:03:48
    password now he would have gotten away
  • 00:03:49
    with it too if it weren't for a pesky
  • 00:03:51
    tenant named andrees who happened to
  • 00:03:53
    notice that his electricity bill was
  • 00:03:55
    just a little bit higher than usual he
  • 00:03:56
    started looking behind the walls and
  • 00:03:58
    found some unexpected wies that led
  • 00:04:00
    right to the unauthorized cameras at
  • 00:04:02
    this point we don't know the true
  • 00:04:03
    identity of the hacker but whoever did
  • 00:04:05
    this was looking to cast a very wide net
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    and because it's protected by a secret
  • 00:04:09
    key can only be exploited by one party
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    XZ was a Sitting Duck because it's
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    extremely popular while also being very
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    boring with a single maintainer
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    whoever's behind this is either an
  • 00:04:18
    extremely intelligent psychopath or more
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    likely a group of state sponsored
  • 00:04:22
    Dimension hopping lizard people hellbent
  • 00:04:24
    on world domination and that's why the
  • 00:04:25
    only drro you should use is Temple OS
  • 00:04:28
    this has been the code report thanks for
  • 00:04:29
    watching watching and I will see you in
  • 00:04:31
    the next one
Tags
  • Linux
  • XZ compression
  • security
  • backdoor
  • Debian
  • software vulnerability
  • supply chain attack
  • open source
  • malicious code