MID-064: Store Critical Code and Data in On-Chip Memory
Mitigation Tier: Intermediate
Description
On-chip non-volatile storage in a processor can be used to protect high-value data from extraction and modification. Many processors include ROM, NVRAM, or specialized write-once storage (e.g. security fuses). Common implementation patterns include storing keys and bootloader code used to bootstrap loading further stages of encrypted firmware (see MID-054) from external storage and to verify its authenticity as part of a secure boot chain. In other applications, the device firmware may be small enough to fit entirely within such on-chip storage (see MID-055).
Note: MID-058 must be implemented as well to obtain the protection afforded by this mitigation.
Limitations: Motivated attackers may resort to invasive and destructive analysis of ICs which can extact data or reset security fuses. In the case of keys and other secrets, combining this mitigation with MID-033 can prevent an invasive attack from affecting more than the single device attacked.
IEC 62443 4-2 Mappings
- EDR / HDR / NDR 3.11 (1) - Physical tamper resistance and detection