Time Lord's adventures: abusing time on Linux systems (WHY2025)

What happens when an attacker controls time on a Linux system? This talk looks at how system clocks work, and what breaks when they’re manipulated. From bypassing delays to triggering subtle logic errors, we’ll explore how unstable time can subvert assumptions, break security controls, and cause software to behave in unexpected or unsafe ways. This talk explores the consequences of full control over time on a Linux system. We’ll start with a brief overview of how system clocks work, highlighting common assumptions made by applications and security mechanisms. The focus will be on local manipulation of the system clock — jumping forward, rewinding, or freezing time — and the unexpected ways software can break when time becomes unreliable. Through practical examples, we’ll see how time-based defences and logic can be bypassed, exposing vulnerabilities that often go unnoticed. Not every issue leads to a full exploit, but many reveal fragile trust assumptions rarely tested in real environments. This talk is for hackers, tinkerers, and developers who’ve ever relied on `sleep(1)` as a defence mechanism. You might rethink your assumptions about time-based security after attending. Licensed to the public under https://creativecommons.org/licenses/by/4.0/ about this event: https://program.why2025.org/why2025/talk/NZRWGU/