NTDS.dit

NTDS.dit (C:\Windows\NTDS\ntds.dit) is the Active Directory database — the file where a domain controller stores the entire domain partition: users, groups, computers, and — the part attackers care about — password material (NT hashes, Kerberos keys, and password history) for every account in the domain. Each DC in a domain carries its own copy and keeps it consistent with peers via the DRSUAPI (MS-DRSR) replication protocol, so a write on one DC propagates to the rest.

Because the file is locked by the AD service while the DC is running, grabbing it requires one of three broad approaches:

ApproachMechanism
DCSyncAsk the DC to replicate the secrets to you over MS-DRSR — no file access needed. Requires replication rights (DA-equivalent). See drsuapi.
Volume Shadow CopySnapshot the volume (vssadmin create shadow), then copy ntds.dit from the snapshot. Needs local admin on the DC.
IFM / backup mediantdsutil "ac in ntds" "ifm" ... produces an Install From Media copy, or lift the file from DC backups.

The database is ESE (Extensible Storage Engine) format; raw file in hand, you still need the SYSTEM registry hive from the same DC — its boot key decrypts the per-column encryption on the secret attributes. Tools that pair the two (secretsdump.py, ntdsutil + esentutl, Mimikatz lsadump::dcsync /offline) recover every account’s NT hash and Kerberos keys — including krbtgt, which is everything needed for golden tickets, and every user hash for pass-the-hash / offline cracking.

MITRE: T1003.003 — OS Credential Dumping: NTDS.

Sources