SPD, or Serial Presence Detect, is the metadata stored on a RAM module that tells the system what the memory is and how to configure it. It is usually read from an EEPROM chip on the DIMM during boot. SPD data can include size, speed, timings, voltage requirements, and supported profiles, allowing the firmware and operating system to initialize memory correctly.
SPD matters in cyber security because the platform often trusts it early in startup, before many defenses are fully active. If SPD data is missing, malformed, or manipulated, a machine may misconfigure memory, become unstable, or boot with assumptions that weaken higher-level protections. In attacks, researchers may target memory-module metadata to influence low-level behavior or create conditions that affect firmware and security controls. Defenders reduce risk by using validated hardware, updating BIOS or UEFI firmware, and checking that memory configurations match approved platform settings.