Linux got wrecked by backdoor attack

Fireship

1 Apr 202404:32

Summary

TLDRThe open source community faces a critical security crisis as a sophisticated supply chain attack compromises the XZ compression tool, affecting numerous Linux distributions. The attack, which grants unauthorized code execution via a secret backdoor, is discovered by software engineer Andre Frin. The malicious code, hidden in the liblzma library and requiring the attacker's private key, raises questions about the perpetrator's identity, with suspicions ranging from individual hackers to state-sponsored entities. The incident underscores the importance of vigilance in software security.

Takeaways

🚨 A sophisticated supply chain attack has affected the XZ compression tool, impacting various Linux distributions like Debian, CentOS, and openSUSE.
🔒 The attack introduced a secret back door, allowing unauthorized execution of code on affected machines through the XZ utility.
⚠️ This security breach is considered a Threat Level Midnight 10.0, indicating a critical issue on the CVE RoR scale, surpassing the severity of known bugs like Heartbleed and Shellshock.
🎯 The XZ back door relies on the lzma algorithm, which is widely used in Linux distributions and is also a part of the SSH daemon (sshd).
🤝 The liblzma library, which is compromised, is utilized by many software applications for compression functionalities.
🔍 The malicious code was obfuscated and injected during the build process, modifying the lzma code to enable data interception and manipulation.
🔐 The back door's payload must be signed with the attacker's private key, ensuring that only the attacker can exploit the vulnerability.
💡 The vulnerability was discovered by chance by a software engineer, Andre Frin, who noticed unusual CPU usage while benchmarking on Debian's unstable branch.
🌐 The potential impact could have been disastrous, given that the majority of internet servers run on Linux.
🛑 The attacker's identity remains unknown, with suspicions ranging from an individual to a state-sponsored group, possibly from countries like Russia, North Korea, or the United States.

Q & A

What is the main issue discussed in the video?
-The main issue discussed is a highly sophisticated and carefully planned attack affecting the XZ compression tool, which has been shipped to production and compromised various Linux distributions.
How does this attack rank in terms of severity?
-This attack is considered a Threat Level Midnight 10.0 critical issue on the CVE RoR scale, even higher than famous bugs like Heartbleed, Log4Shell, and ShellShock.
Which operating system is mentioned as being unaffected by the XZ back door?
-Temple OS is mentioned as being unaffected by the XZ back door.
What is XY utils and why is it significant in this context?
-XY utils is a tool for compressing and decompressing streams based on the Lempel-Ziv-Markov chain algorithm (LZMA). It contains a command-line tool installed on most Linux distributions by default and an API library called liblzma, which many other pieces of software depend on for compression.
How was the back door discovered?
-The back door was discovered by pure luck when a software engineer named Andre Marinescu was using the unstable branch of Debian to benchmark PostgreSQL. He noticed that SSH logins were using more CPU resources than normal, which led him to investigate and ultimately identify the issue in XY utils.
What is the role of the liblzma library in this security breach?
-The liblzma library, which is part of XY utils, contains the back door. Malicious code was found in the tarballs of liblzma, which is what most people install. The code is obfuscated and injects a pre-built object disguised as a test file during the build process, allowing the attacker to intercept and modify data that interacts with this library.
What is unique about the payload sent to the back door?
-The payload sent to the back door must be signed by the attacker's private key, meaning only the attacker can send a payload to the back door. This makes it more difficult to test, monitor, and adds a layer of protection for the attacker.
Who is suspected of introducing the malicious tarballs?
-A contributor to the liblzma project named 'gian' is suspected of introducing the malicious tarballs. This individual has been a trusted contributor for the last few years and has been building up trust before attempting this back door.
What is the potential impact of this back door on the internet?
-Since the vast majority of servers that power the internet are Linux-based, this back door could have been a major disaster. However, it was discovered early on, which helped to avoid a potential multi-billion dollar disaster.
What is the significance of the name 'Andre Marinescu' in this context?
-Andre Marinescu is the hero software engineer who discovered the back door while using the unstable branch of Debian. His last name translates to 'friend' in German, which is fitting as he single-handedly helped the world avoid a major disaster.
What is the current state of understanding regarding the true identity of the hacker?
-At this point, it is unclear who is behind the attack. It could be an individual, a group of state-sponsored hackers, or even a rogue state like Russia, North Korea, or the United States.
What is the recommended course of action for those using the affected Linux distributions?
-Users of the affected Linux distributions are advised to upgrade their systems immediately to mitigate the risk and potential impact of the XZ back door.

Outlines

00:00

🚨 Urgent Security Crisis in the Open Source World

The open source community has been thrown into a state of panic due to a highly sophisticated and meticulously planned attack on the XZ compression tool. This supply chain attack has compromised various Linux distributions, including Debian CI, open Suse, and others. Fortunately, Temple OS remains unaffected. The severity of this issue is unprecedented, surpassing even notorious vulnerabilities like Heartbleed and Shellshock. The video aims to explain the workings of the XZ back door and the remarkable story of its accidental discovery. It is crucial for users of the affected Linux distributions to upgrade their systems immediately, as this back door could have led to a catastrophic event had it not been discovered early.

Mindmap

Keywords

💡Open Source

Open source refers to a type of software licensing where the source code is made publicly available for inspection, modification, and enhancement. In the context of the video, the open source community is in a state of panic due to a security breach in a widely used tool, highlighting the importance of open source's collaborative nature in maintaining and securing software.

💡Supply Chain Attack

A supply chain attack is a type of cyber attack where the vulnerability is introduced into a software application through its development, distribution, or management process. In the video, this term is used to describe the infiltration of the XZ compression tool, which is a critical component in the software supply chain of several Linux distributions.

💡Linux Distros

Linux distributions, or distros, are variations of the Linux operating system that are tailored for specific uses, hardware, or user preferences. The video discusses how certain Linux distros, such as Debian and openSUSE, are affected by the security breach in the XZ compression tool.

💡Back Door

A back door in software is a hidden入口 or access point that bypasses normal authentication or security measures, allowing unauthorized access or control. In the video, the discovery of a back door in the XZ compression tool is a critical security issue, as it provides attackers with a covert way to execute code on affected systems.

💡CVE RoR Scale

The CVE RoR (Range of the Vulnerability Ecosystem) Scale is a method for rating the risk posed by a cybersecurity vulnerability based on its impact on the ecosystem. The video emphasizes the severity of the XZ compression tool breach by stating it as a 'Threat Level Midnight 10.0 critical issue on the CVE RoR scale,' which is even higher than other famous bugs like Heartbleed and Shellshock.

💡LZMA

LZMA stands for Lempel-Ziv-Markov chain Algorithm, which is a compression algorithm used by the XZ compression tool. The video explains that the XZ compression tool contains a command-line tool and an API library called liblzma, which is widely used by other software, including SSH, to implement compression.

💡SSH (Secure Shell)

SSH, or Secure Shell, is a protocol that provides a secure channel over an unsecured network for remote login and other secure network services. In the video, the security breach in the XZ compression tool potentially affects SSH because it relies on the liblzma library for compression, which has been compromised.

💡Obfuscation

Obfuscation refers to the process of making code difficult to understand by intentionally making it complex, using misleading names, or employing other techniques to hide its true purpose. In the context of the video, the attackers used obfuscation to hide the malicious code within the XZ compression tool, making it challenging to detect and understand.

💡Private Key

A private key, in the context of cryptography, is a unique piece of data that is used to decrypt or sign messages and transactions. In the video, the back door in the XZ compression tool can only be exploited if the payload sent to it is signed by the attacker's private key, ensuring that only the attacker can send a payload and maintain control over the back door.

💡Andre Frin

Andre Frin is a software engineer who discovered the security breach in the XZ compression tool by accident. His last name, which translates to 'friend' in German, is fitting as he helped the world avoid a major disaster by uncovering the issue.

💡Lassie Colin

Lassie Colin is the maintainer of the liblzma project, which was targeted in the supply chain attack. The malicious tarballs were associated with this project, and while Lassie Colin is not suspected of being involved, the attacker used his project as a means to distribute the compromised XZ compression tool.

Highlights

The open source world is in panic due to a sophisticated attack on the XZ compression tool.

The attack has compromised Linux distributions like Debian, CI, openSUSE, and others.

Temple OS remains unaffected by this security breach.

This incident is considered one of the most well-executed supply chain attacks in history.

The threat level is rated 10.0 on the CVE RoR scale, higher than famous bugs like Heartbleed and Shellshock.

The XZ back door works by injecting a pre-built object disguised as a test file during build time.

The malicious code modifies the lzma code to intercept and alter data interacting with the library.

The payload sent to the back door must be signed by the attacker's private key, limiting access to the creator.

The attacker obfuscated the code to avoid detection, with no obvious characters and a built-in state machine to recognize important strings.

Linux-based servers, which power the majority of the internet, could have been severely impacted by this back door.

Andre Frin, a software engineer, discovered the issue by accident while benchmarking PostgreSQL on an unstable branch of Debian.

SSH logins were using more CPU resources than normal, which initially led Frin to investigate further.

The liblzma project is maintained by Lassie Colin, but the malicious tarballs were passed by giaan, a trusted contributor.

Giaan, or the group behind this, spent years building trust before implementing the back door without notice.

The true identity of the hacker remains unknown, and it is unclear whether it is an individual or a state-sponsored group.

The attack aimed to exploit the popularity and single maintainer status of XZ, making it a sitting duck.

The discovery by Andre Frin helped the world avoid a potential multi-billion dollar disaster.

The story serves as a reminder of the importance of security in open source software and the potential risks of supply chain attacks.