This lesson explains steganography — hiding data inside innocuous carriers — and contrasts it with encryption. It covers common carriers and techniques, attacker use cases, a quick LSB embedding primer, detection and defensive strategies for defenders, trade-offs, ethics, and practical takeaways for purple-team defenders.
Steganography Concepts and Use Cases — The Art of Hiding in Plain Sight "If encryption is whispering secrets in a locked diary, steganography is slipping the diary into a book about knitting and pretending nothing happened." You're already fluent in the language of access, escalati...
What is steganography (and how is it not the same as encryption)? Steganography : the practice of concealing a message or data inside another file or channel so it appears innocuous. The goal is stealth — make it look like nothing is there. Encryption : turning data into unreadable gibberish — l...
Why this matters in system hacking For attackers: stego provides covert command-and-control (C2), hidden payload delivery, and quiet data exfiltration that can slip past content scanners and careless monitoring. For defenders: detecting stego often requires different tooling and an operational m...
Common steganography carriers and techniques 1) Image files (the classic) LSB (Least Significant Bit) embedding : swap the least important bits of pixels with data bits. Small visual impact, big stealth potential on large images. Metadata/EXIF stuffing : shove text or encoded blobs into metada...
How attackers use stego (practical use cases) Covert C2 : periodic innocuous-looking image downloads that carry encoded commands. Defender sees a cat meme; operator gets a remote control message. Data exfiltration : hide small chunks of sensitive data inside outbound images or DNS queries. Ini...
Quick primer: LSB embedding (pseudocode) # Pseudocode — conceptual only def embed_lsb(cover_image, secret_bytes): pixels = cover_image.get_pixels() bitstream = to_bitstream(secret_bytes) for i, bit in enumerate(bitstream): pixel = pixels[i] pixel.blue = set_lsb(pixel.blue, bit) return cover_...
Detection and defensive strategies (what defenders should actually do) Detecting stego is harder than detecting malware with signatures. Here’s a layered approach that maps back to what we learned about EDR, rootkits, and hardening: Reduce the attack surface Restrict permissible file types th...
Trade-offs & contrasting perspectives Attackers: stego is stealthy but has capacity limits and may be brittle (noise, recompression, resizing can break it). Defenders: detection is expensive and noisy — large-scale steganalysis can overwhelm analysts with false positives. Table: Quick comp...
Ethical and operational considerations Steganography tools are dual-use. In a defensive/ethical hacking context, the goal is to understand attacker tradecraft to build mitigations. Always follow rules of engagement and legal boundaries when testing. Closing — Key takeaways (so you can flex in th...
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