payloadswapping

Payload swapping refers to the deliberate replacement of a software payload during its delivery to a target system, with the intent that the final executed code differs from what the recipient expects. In security contexts, payload refers to the code, data, or instructions that will run after initial access, software deployment, or an update.

The technique can occur in various stages: during software update workflows where an updater component accepts a payload from a server and installs it; during distribution of malware where a dropper swaps a benign payload with a malicious one; during firmware or hardware supply chains where a firmware image is intercepted and replaced before installation. In many cases it is associated with man-in-the-middle attacks, compromised distribution infrastructure, or misuse of trusted update mechanisms.

Defenses include strong code signing and verification of payload integrity, end-to-end encryption and integrity checks of update channels, secure boot and measured boot with hardware root of trust, reproducible build processes, and anomaly detection in update servers. Organizations should implement strict supply chain security, monitor for unexpected changes in payload manifests or hashes, and require multi-party approvals and tamper-evident logs. User-level defenses include keeping devices updated and enabling automatic verification of digital signatures.

Related topics include supply chain attacks, man-in-the-middle attacks, and code signing, as well as broader concepts in software distribution security.