Code Signing

Code Signing
Mitigation
ID	M0945
NIST SP 800-53 Rev. 4	SI-7
IEC 62443-3-3:2013	SR 3.4
IEC 62443-4-2:2019	CR 3.4

Description

Enforce binary and application integrity with digital signature verification to prevent untrusted code from executing.

Techniques Addressed by Mitigation

Name	Use
Masquerading	Require signed binaries.
Modify Controller Tasking	Utilize code signatures to verify the integrity of the installed program on safety or control assets has not been changed.
Modify Program	Utilize code signatures to verify the integrity of the installed program on safety or control assets has not been changed.
Module Firmware	Devices should verify that firmware has been properly signed by the vendor before allowing installation.
Program Download	Utilize code signatures to verify the integrity of the installed program on safety or control assets has not been changed.
Project File Infection	Allow for code signing of any project files stored at rest to prevent unauthorized tampering. Ensure the signing keys are not easily accessible on the same system.
Rootkit	Digital signatures may be used to ensure application DLLs are authentic prior to execution.
Supply Chain Compromise	When available utilize hardware and software root-of-trust to verify the authenticity of a system. This may be achieved through cryptographic means, such as digital signatures or hashes, of critical software and firmware throughout the supply chain.
System Firmware	Devices should verify that firmware has been properly signed by the vendor before allowing installation.
User Execution	Prevent the use of unsigned executables, such as installers and scripts.