XZ backdoor: Hook analysis


In their first article on the XZ backdoor, Kaspersky researchers analyzed its code from initial infection to the function hooking it performs. As they mentioned then, its initial goal was to successfully hook one of the functions related to RSA key manipulation.

In this article, the research team will focus on the backdoor’s behaviour inside OpenSSH, specifically OpenSSH portable version 9.7p1 – the most recent version at this time. To better understand what’s going on, they recommend you to read Baeldung’s article about SSH authentication methods and JFrog’s article about privilege separation in SSH.

Read more…
Source: Kaspersky


Sign up for our Newsletter


Related:

  • Ghostcommit attack hides malicious AI instructions in images

    July 13, 2026

    Ghostcommit is a proof of concept that shows how AI assistants used to review software code can be tricked by hidden instructions embedded in images. The academic ASSET Research Group showed that an attacker can place instructions inside an image file, point to it in an AGENTS.md file, and get an AI coding agent to follow those instructions during a ...

  • GigaWiper: Anatomy of a destructive backdoor assembled from multiple malware

    July 9, 2026

    In October 2025, Microsoft Threat Intelligence identified destructive wiping activity and uncovered a sophisticated Go programming language (Golang)-based backdoor we now track as GigaWiper, a versatile implant that combines robust command-and-control (C2) capabilities with multiple destructive payloads, including disk wiping, fake ransomware, and system-level sabotage. GigaWiper is particularly notable for its makeup. It’s not a single, ...

  • Vidar Stealer Unmasked: Code Signing Abuse, Go Loaders and File Inflation

    July 7, 2026

    In April 2026, Unit 42 researchers identified a financially motivated campaign delivering Vidar stealer and the XMRig cryptocurrency miner to consumer and small- and medium-sized business victims worldwide. Attackers lure victims via malvertising to pages for downloading files that impersonate cracked versions of copyright-protected software. Upon execution, the loader drops and runs both Vidar stealer and ...

  • Self-destructing Mistic backdoor linked to access broker selling corporate footholds to ransomware gangs

    June 25, 2026

    A new self-destructing backdoor called Mistic used in intrusions since April appears to be linked to a criminal gang that compromises corporate networks and then sells that access to ransomware groups, according to security researchers. This backdoor, also tracked as MLTBackdoor, was first documented by Zscaler earlier this month, with the security shop suggesting the novel malware is ...

  • A VBScript campaign distributed through WhatsApp deploying RMM software

    June 22, 2026

    In June 2026, Kaspersky observed a malware campaign distributing malicious VBScript files through direct messages in WhatsApp. The campaign affected users across multiple countries and territories, including Malaysia, Brazil, India, Mexico, Singapore, UK, Spain, Taiwan, Australia, Russia and Vietnam, with the highest number of victims observed in Malaysia. At the time of writing this article, ...

  • Dozens of malicious wallpapers found on Steam Workshop

    June 16, 2026

    Since late 2025, malware has been spreading rapidly through the Steam Workshop, the gaming platform’s built-in service for players to create and share custom content. The attackers are primarily targeting gamers in China and Russia, aiming to hijack their accounts. To pull this off, they are exploiting Wallpaper Engine – a popular live wallpaper app ...