They did not break in: they published. That line from the Beagle Brigade team sums up how package registry malware works. A stolen maintainer token becomes a new version of a package you already depend on, and it runs on every laptop and CI runner that installs it, before anyone opens a file. Their project took second place in our Semgrep Guardian challenge at the Cyberdefense Hackathon during SF Tech Week. Each new release on a registry like npm or pypi is pulled into a sandbox. It’s analyzed with Semgrep dataflow rules without ever being executed. Anything suspicious goes to an AI agent that returns a verdict. What we liked most is that the analysis never runs what it downloads. When the threat is code that executes on install, analysis that doesn’t execute anything is the safe place to start. It’s the same threat Semgrep Guardian’s malware firewall is built for with malicious dependencies. Congrats to the Beagle Brigade team! #SFTechWeek#