A security engineer at a bank has detected a Zeus variant, which relies on covert communication channels to receive new instructions and updates from the malware developers. As a result, NIPS and AV…

Perfect forward secrecy is a cryptographic key exchange property that protects past session keys if long-term keys are compromised, and has no function in concealing data inside normal-looking files.

Steganography is the technique of concealing data within ordinary-looking carrier files such as images or documents, making the hidden payload invisible to tools that inspect content for known malicious signatures. By embedding command-and-control configuration updates inside seemingly benign email attachments, the malware developers created a covert channel that NIPS and AV systems could not detect because the files matched no known threat pattern and appeared structurally legitimate.

Diffusion is a cryptographic design principle that disperses the influence of plaintext bits across ciphertext, not a method for embedding hidden instructions inside carrier files.

Confusion is a cryptographic principle that obscures the statistical relationship between a key and ciphertext, and does not describe hiding malicious payloads within ordinary files.

Transport encryption protects data in transit over a network but would not cause malicious files to appear as normal, legitimate attachments to host-based AV or inline NIPS inspection.