Subvert Trust Controls: Code Signing
Adversaries may create, acquire, or steal code signing materials to sign their malware or tools. Code signing provides a level of authenticity on a binary from the developer and a guarantee that the binary has not been tampered with.  The certificates used during an operation may be created, acquired, or stolen by the adversary.   Unlike Invalid Code Signature, this activity will result in a valid signature.
Code signing to verify software on first run can be used on modern Windows and macOS/OS X systems. It is not used on Linux due to the decentralized nature of the platform. 
Code signing certificates may be used to bypass security policies that require signed code to execute on a system.
This type of attack technique cannot be easily mitigated with preventive controls since it is based on the abuse of system features.
Collect and analyze signing certificate metadata on software that executes within the environment to look for unusual certificate characteristics and outliers.
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