Firmware diffing at scale for silent patch detection

The silent patch problem

Vendors sometimes fix memory corruption without publishing an advisory. Customers then have no signal that an update matters, and many leave it uninstalled for years.

The pipeline

Each firmware release is unpacked, analysed with Ghidra in headless mode, and compared against the previous build with BinDiff. Functions with small, bounds-related changes are ranked for human review.

What we learned

Most changes are boring. The few that are not are easy to miss by hand. Automation does not replace an analyst here. It tells the analyst where to look first.