Once a new user or group is created and assigned that specific SID, they automatically inherit all the "synthetic" permissions previously injected, often without appearing in standard audit logs as a new permission grant. Why This Matters
This attack involves threat actors with existing high privileges injecting "synthetic" into an Active Directory Access Control List (ACL) . This allows attackers to pre-assign permissions to a SID that does not yet exist in the environment, creating a silent "backdoor" that activates the moment a new account is created with that matching SID. Key Mechanics of the Attack
For more detailed technical analysis, you can view the original research on the Varonis Blog .
Is This Sid Taken? Varonis Hazard Labs Finds Synthetic Sid Shot Assault -
Once a new user or group is created and assigned that specific SID, they automatically inherit all the "synthetic" permissions previously injected, often without appearing in standard audit logs as a new permission grant. Why This Matters
This attack involves threat actors with existing high privileges injecting "synthetic" into an Active Directory Access Control List (ACL) . This allows attackers to pre-assign permissions to a SID that does not yet exist in the environment, creating a silent "backdoor" that activates the moment a new account is created with that matching SID. Key Mechanics of the Attack Once a new user or group is created
For more detailed technical analysis, you can view the original research on the Varonis Blog . Once a new user or group is created