arXiv:2508.14261v2 Announce Type: replace Abstract: Embedded devices powering cyber-physical systems (CPS) are increasingly internet-exposed, placing critical infrastructure under active threat. Dynamic analysis of embedded malware requires a sandbox that provides a realistic embedded environment, captures system-level side channels for behavioral insight, and supports repeatable experiments. Existing Linux sandboxes fall short on all three: they target narrow tasks, run minimal environments, and only execute samples directly. Malware often withholds its true behavior, awaiting environmental triggers or command-and-control (C2) servers, or deploying anti-analysis techniques. To address these issues, we present SaMOSA (sandbox for malware orchestration and side-channel analysis), with \emph{on-demand C2 response replay} via a \emph{replay formulation} tool to extract and serve C2 payloads, \emph{lifecycle-bound orchestration} for environment customization, four synchronized side-channels, and multi-architecture support. Among Linux sandboxes targeting CPS, only SaMOSA provides both on-demand C2 response replay and lifecycle-bound orchestration, serving payloads over malware-initiated sessions for network-isolated execution without live infrastructure. Through a Kinsing cryptominer case study on ARM64, we show that SaMOSA delivers the full C2 payload chain without live infrastructure, with synchronized channels resolving phase-wise mining behavior under live C2. Replay reproduces payload delivery but not stateful C2 sessions, a fidelity boundary that surfaced a hidden Tor fallback and 59 new IPs.