The sample arrived with the confidence of something that had beaten analysts before. It was right to be confident. It was wrong to leave a taunt in .rdata where I would eventually find it.
The packer
A custom stub, self-modifying, with a hand-rolled checksum over its own .text so a single breakpoint would corrupt the decryption key downstream. Classic. The fix is to let it unpack itself and dump the reconstructed image at the original entry point rather than fighting the anti-debug at every step.
The anti-analysis buffet
Timing checks (rdtsc deltas), a IsDebuggerPresent it clearly didn’t trust, a check for common sandbox artifacts, and — my favorite — a routine that only behaved maliciously if the mouse had moved recently. Automated sandboxes don’t fidget. Analysts do.
The smug string
Once unpacked, the config decrypted cleanly, and there it was in .rdata: "if you are reading this, hi :)". Hi back. The writeup, and the signatures, followed.