Varonis Hazard Labs Finds Synthetic Sid Shot Assault - Is This Sid Taken?
Yes, identified a technique known as Synthetic SID Injection .
These synthetic entries often appear as "Account Unknown" or long strings of numbers in the security tab, which administrators frequently ignore as remnants of deleted accounts rather than active threats. Yes, identified a technique known as Synthetic SID Injection
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 This allows attackers to pre-assign permissions to a
A low-level account created later can suddenly "wake up" with Administrative or Domain Admin rights if those rights were pre-injected into the synthetic SID. 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 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
Yes, identified a technique known as Synthetic SID Injection .
These synthetic entries often appear as "Account Unknown" or long strings of numbers in the security tab, which administrators frequently ignore as remnants of deleted accounts rather than active threats.
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
A low-level account created later can suddenly "wake up" with Administrative or Domain Admin rights if those rights were pre-injected into the synthetic SID.
For more detailed technical analysis, you can view the original research on the Varonis Blog .
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
