The xz sshd backdoor rabbithole goes quite a bit deeper (twitter.com)

Article summary

A researcher has discovered a sophisticated backdoor in the xz sshd, which allows for remote code execution and potentially full authentication bypass. The backdoor is triggered by sending a crafted command to the RSA_public_decrypt hook, and it involves a complex process of installing another hook and sending fake ssh-rsa pubkeys. The researcher has confirmed the existence of the backdoor and is still exploring its functionality. The discovery has sparked a discussion about the potential for other undetected backdoors in open-source software.

Main themes

• xz sshd backdoor
• Remote code execution
• Authentication bypass
• Open-source software security
• Backdoor detection

What commenters say

• The discovery of the xz sshd backdoor is a significant finding, but it raises concerns about the potential for other undetected backdoors in open-source software.
• The complexity of the backdoor suggests that it was designed to be difficult to detect, and its existence may have gone unnoticed for a long time.
• The fact that the backdoor was discovered through a performance regression suggests that it may have been introduced intentionally, rather than being a accidental vulnerability.
• Some commenters believe that the existence of this backdoor does not necessarily mean that there are many others like it, as it is a highly complex and sophisticated piece of code.
• Others argue that the lack of detection of other backdoors does not mean they do not exist, and that there may be many more waiting to be discovered.
• There is a need for more eyes on open-source code to detect and prevent backdoors, and some suggest that online tools and platforms could be developed to facilitate this process.
• The discovery of the backdoor has sparked a debate about the trade-offs between security and convenience, with some arguing that the benefits of open-source software outweigh the risks.