El Hackeo que casi INFECTA al MUNDO ENTERO | La puerta trasera de xzutils

Summary

This video details a sophisticated supply chain attack targeting the XZ Utils open-source software. The attacker, 'Jatan', inserted a backdoor during the compilation process, exploiting SSH's RSA authentication function to enable remote command execution. The vulnerability was discovered by a vigilant developer, leading to a swift response and the removal of the malicious code. This attack highlights the risks of relying on open-source software and the potential dangers posed by even subtle vulnerabilities, stressing the need for enhanced security measures in both community-driven and corporate-backed projects.

Takeaways

• 😀 A supply chain attack was carried out on the open-source software *xz-utils*, affecting its compilation process.
• 😀 The attacker, known as Jatan, introduced malicious code during the compilation stage that modified the SSH rsa_public_decrypt function.
• 😀 The backdoor allowed remote attackers to execute commands on vulnerable systems without knowing the password.
• 😀 The malicious code was hidden in test files that were used only during compilation, making it difficult for developers to detect.
• 😀 The attacker, Jatan, had built a reputation as a meticulous contributor, making it harder for anyone to suspect his involvement.
• 😀 The vulnerability was detected by a developer named Andrés, who noticed unusual delays in the system’s processing times.
• 😀 If the malicious code had gone unnoticed, it could have affected many Linux systems after they updated their software.
• 😀 Some Linux distributions, like Gentoo and Arch Linux, were not affected because they didn’t directly link SSH with *xz-utils* updates.
• 😀 The incident highlights the risks of supply chain attacks, where attackers compromise software during development rather than targeting end-users directly.
• 😀 The story also underscores the false sense of security that can arise from the transparency of open-source projects, where anyone can review the code.

Q & A

What is the primary focus of the video script?

The primary focus of the video script is explaining a security breach that occurred in XZ Utils, a software library used in Linux systems, and how a malicious actor exploited the compilation process to insert a backdoor into the software.

How do Linux distributions typically use XZ Utils?

Linux distributions like Debian use XZ Utils by downloading the source code, compiling it, and packaging it for end users. This compiled version is what users install and use on their systems.

What role does the compilation script play in the attack?

The compilation script normally checks the system's compatibility and prepares the software for compilation. However, in this attack, the script was modified to secretly insert malicious code during the compilation process, which went undetected in the official source code.

What is the function `rsa_public_decrypt` used for in SSH?

The `rsa_public_decrypt` function in SSH is used for handling RSA public key decryption, which is a core part of the authentication process that allows users to securely log into remote systems.

How did the malicious code affect SSH authentication?

The malicious code modified the `rsa_public_decrypt` function, allowing attackers to execute remote commands on the system, even without knowing the system's password. This created a backdoor for unauthorized access.

How was the malicious code hidden during the compilation process?

The malicious code was hidden inside test files that were included during the compilation process. These files were not part of the main codebase and went unnoticed by most developers or users, making it difficult to detect the breach.

Who discovered the malicious code, and how was it identified?

The malicious code was discovered by Andrés, who noticed unusual delays during SSH logins. After further investigation, it was determined that the delay was caused by the compromised `rsa_public_decrypt` function, which led to the identification of the attack.

Why did the attack not affect all Linux distributions equally?

The attack did not affect all distributions equally because some, like Debian and Ubuntu, linked XZ Utils directly to system libraries, making them vulnerable. Other distributions, like Gentoo or Arch Linux, did not, so the vulnerability did not manifest there.

What is a supply chain attack, and how does it relate to this incident?

A supply chain attack targets the developer or distributor of software rather than the end user. In this case, the attacker modified the XZ Utils source code during the compilation process, inserting a backdoor that was then distributed to users through legitimate channels.

What is the main takeaway about the open-source software ecosystem from this incident?

The main takeaway is that while open-source software offers transparency, it can also create a false sense of security. The XZ Utils attack demonstrated how vulnerabilities can be introduced during the compilation process, even though the source code itself appears safe.