The author investigates a production outage at Endcrawl caused by a bug in kill(1), a utility 50 years old, triggered by sending SIGTERM to a negative process group ID. The investigation revealed the bug affected Ubuntu 14, 16, 18, 22, and 24 LTS releases, spanning a decade of shipped code.
Background
The kill command has been a core Unix utility since the early 1970s, used to send signals to processes. This article documents a deep debugging investigation into a previously unknown vulnerability in its process group handling logic.
- Source
- Lobsters
- Published
- Nov 3, 2026 at 05:23 AM
- Score
- 7.0 / 10