Let's Avoid Doing Math

DawgCTF SP26

Task: a validation log records known and detected threat-depth classes for 120 malware samples, and the flag is built from per-class accuracy, FPR and FNR values. Solution: reconstruct the confusion matrix from the log, then report (accuracy, FPR, FNR) for each class in ascending severity order — the trap is that 'for each classification' applies to accuracy too, so the flag has nine per-class values and no single overall accuracy.