Trigon -- Deterministic Kernel Exploit

Trigon is a notable iOS kernel exploit because it is deterministic – it does not rely on race conditions. While most kernel exploits need to run multiple times to win a race, Trigon works reliably every time.

Overview

Field Detail
Developer alfiecg_dev
Published March 2025
Write-up alfiecg.uk
Key innovation Deterministic exploitation (no races)

Why Deterministic Matters

Typical kernel exploit:
  Attempt 1: race lost → crash (kernel panic → reboot)
  Attempt 2: race lost → crash
  Attempt 3: race won → success!
  → User experience: device reboots several times

Trigon:
  Attempt 1: success (always)
  → Reliable, no crashes, better user experience
  → Important for jailbreak tools (users don't want random reboots)

Techniques

  • Avoids race conditions entirely
  • Uses deterministic memory layout manipulation
  • Precise heap grooming for guaranteed object adjacency
  • Careful control of kernel allocator behavior

Resources