Have you ever imagined compromising almost every user of a major Linux distribution?

apt upgrade. apk add. dnf update. Every day, millions of servers execute these commands with absolute trust, relying on signatures to guarantee that an update is safe and official. But this only proves that a file successfully passed through a signing service at the very end of its journey. It does not validate the integrity of the massive, automated factory that built, processed, and advertised it. What happens when an attacker targets the distribution control plane itself?

Over several months, we audited the backend infrastructure powering major Linux distributions, including Ubuntu, Alpine, and Fedora. Moving beyond common supply chain threats, we focused on the internal systems that decide what becomes official. We discovered multiple independent compromise chains that allowed us to subvert the software supply chain entirely from the inside. By exploiting flawed trust boundaries in build artifact processing, over-privileged automation workflows, and logical gaps in metadata generation, we demonstrated how attackers can trick official infrastructure into blindly building, stamping, and delivering malicious updates to users.

This talk pulls back the curtain on the hidden complexity of modern software distribution. Join us to explore how backend pipelines can be compromised and weaponized.

The package was signed. The pipeline wasn't.