Some ThinkNode M9 cards shipped with a dormant Windows worm (Elecrow
security advisory, September 2026). An infected card seen since carries
autorun.inf in the root, launching xlfqf.pif on open, explore and autoplay
with random-junk comment lines in between: the Sality autorun pattern.
- SD Scan store app (deploy/apps/sdscan/1.0, requires "sd", not seeded):
walks the card a small page per tick, lists what it finds and why, and
removes it after a confirmation screen with Cancel first. It says on
every screen that it only removes files it recognises and that
formatting the card is the safe fix. On older firmware it still finds
threats by name but cannot remove them.
- Firmware: wada.sd.check(path) and wada.sd.remove(path), plus paging for
wada.sd.list(path, start, max) and caps().sd_clean. What counts as a
threat lives in SdThreat.h: autorun.inf, Windows program, script and
shortcut extensions, or a real MZ+PE header under any name. remove()
classifies again in firmware and refuses anything else, so no app can
use it to delete tiles, backups or chat history. It clears read-only,
hidden and system first, because FAT refuses to delete a read-only file.
- A warning when a card with Windows malware in its top folder is mounted,
at boot or on insert, offering SD Scan (or the Store).
- Tests: test/test_sd_threat.cpp, and SD Scan harness scenarios including
the real infected card's root. Removal checked on a T-Deck.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
