OysterLoader Evasion Tactics Exposed: Advanced Obfuscation and Rhysida Ransomware Ties Uncovered

OysterLoader is a multi-stage C++ loader used in malvertising and trojanized installer campaigns tied to the Rhysida ransomware ecosystem; it abuses signed MSI packages, employs API‑flooding, custom dynamic API resolution, steganographic and RC4‑protected C2 exchanges, and a custom LZMA‑like unpacker to deploy ransomware or info‑stealers. The report provides technical details on stages, persistence via scheduled tasks, evolving domain/API C2 infrastructure, and actionable IoCs (domains, API paths, filenames) defenders can hunt for to detect and mitigate infections.