SID filtering in complex AD layouts: the one-bit boundary that decides what crosses your forest
September 9, 2025
Quick definition: SID filtering is a trust-side control that removes foreign SIDs—including values in SIDHistory—from a user’s authorization data as it traverses a trust. It prevents privilege escalation by honoring only the SIDs the trusting side expects.
Answer box (at a glance)
External/domain trusts: Quarantine=Yes by default → accept only SIDs from the directly trusted…    
    

