Starting on June 11, 2026, the Arch User Repository (AUR) was targeted by malware which rapidly compromised over 1,500 packages. The AUR repository allows for abandoned community packages to be taken over by a new maintainer, which was exploited by the attackers to claim ownership.
Once the packages were adopted by the malicious maintainers, the next part should sound familiar: The package build scripts, which are executed by the Arch yay and paru package managers, were modified to install malicious NPM packages (atomic-lockfile and js-digest) each containing the now-usual suite of infostealer malware targeting browser credentials and tokens, SSH private keys, package repository tokens, cloud compute, AI tokens, and crypto wallets.
The malware once installed uses several tricks to cloak itself by renaming processes, and to install systemd services to restart itself, and leveraging eBPF filtering in the kernel to hide the sockets and processes further. It specifically targets browsers and Electron-based applications, which are basically a light-weight Chromium browser disguised as an application anyway. Slack, Discord, Signal, and many more use the Electron wrapper.
A preliminary analysis of the malware is available, which breaks down the exact behavior in more detail and lists the known targets of the malware.
Initially believed to be “only” a few hundred packages, the compromised list eventually grew to over 1500, and additional packages may still be discovered. On June 14, Phoronix reported that a second wave of compromised packages has been found in the AUR repositories, including NeoVim plugins and multiple browsers. The second set of infected packages were compromised in a similar fashion, but with more heavily obfuscated scripts.
Steam Wallpaper Malware
Kaspersky Labs finds that Steam users have been targeted by malware uploaded via a popular animated wallpaper application, “Wallpaper Engine”.
While Valve normally does an admirable job filtering the Steam store, it looks like an exploit has slipped through in “Wallpaper Engine”. Animated wallpapers can be videos, web pages, or full executables themselves. Obviously, being able to run any program masquerading as wallpaper directly is an excellent vector to install malware, so of course this is what happened.
Using the integrated Steam Workshop, which allows users to share game mods and other game content directly, malicious wallpapers install a wide variety of malware including the usual gamut of infostealers, remote access, residential proxy, key logging, and crypto miners. This makes it one of the rare times installing crypto miners almost makes sense, considering most Steam users likely have better than average video cards.
Once a user is infected, the malware also steals the current Steam login credentials, and several instances attempt to then upload additional infected wallpapers to the Steam Workshop under the compromised users identity, completing the supply chain circle of life.
Continue reading “This Week In Security: Arch AUR, Steam Marketplace, WordPress All Face Issues, Taco-Themed Coding, And Mythos Makes National News” →
