Png Magic Bytes

Category: FORENSICS · Difficulty: Basic · Points: 100 · Challenge: 480

Background

During a malware staging event, an adversary altered the file signatures and chunk CRC checksums of an internal floor layout graphic to evade automated gateway sandboxing. Restore the damaged structural markers to render the hidden image. FORMAT: FLAG{ }

Analysis

The evidence file is 99 bytes and carries a generator marker followed by a single configuration line. Reading printable runs across the file recovers the value directly:

$ strings -n 8 artifact-038.png
[FORENSIC_TRIAGE_TARGET_038]
CONFIDENTIAL_FLAG=FLAG{cwa2026_2953a5588e6a1db5}

The file holds no filesystem image, no archive structure and no encoded payload beyond the plaintext line above, so the signature and CRC reconstruction work described in the brief was not required.

Result

FLAG{cwa2026_2953a5588e6a1db5}