Cursed Steganography

duckerz

Task: recover a flag hidden in a 64x64 PNG image generated by a DCGAN neural network embedded in a Nuitka-compiled Windows executable. Solution: unpack the Nuitka onefile payload (zstd-compressed), intercept the PBKDF2 passphrase via DLL hooking under Wine, decrypt the AES-GCM encrypted ONNX model, reconstruct it in PyTorch, then perform gradient-based GAN model inversion to recover the latent vector and decode the flag from its sign bits.