Ad Opsec Telemetry

AD OPSEC and Telemetry

Every technique leaves a trace. The goal here is not evasion. It is knowing the noise profile of each action so you can document it for the client before the engagement, pick the quieter of two functionally equivalent techniques, and correlate what you did with what their SOC saw. For a defender, read the same tables backwards: they are the events to monitor and alert on.

Two rules of engagement throughout:

• Document the noise. Tell the client what each high-signal action generated, with the event ID and the source IP, so they can find it in their logs.
• Coordinate the loud ones. DCSync, mass spraying, coercion at scale, and LSASS dumps need explicit client sign-off or an end-of-engagement window when detection no longer matters.

Microsoft Defender for Identity (MDI) is the sensor that matters most in AD; it reads DC traffic directly and ships tuned detections for most of what follows.

Kerberoasting: Event 4769, RC4 (0x17)

Requesting service tickets for accounts with SPNs, to crack offline.

• Event 4769 (Kerberos service ticket requested) fires for each SPN targeted. The tell is Ticket Encryption Type = 0x17 (RC4-HMAC). Attackers request RC4 because the resulting hash cracks fastest, but a service that normally uses AES suddenly requested with RC4 is the classic signature.
• MDI: "Suspected Kerberoasting attack" is on by default and triggers on the volume and RC4 pattern.
• Requesting all SPNs at once amplifies the signal. Targeting one high-value account is far quieter than roasting the whole domain.

GetUserSPNs.py corp.local/user:pass -dc-ip <dc_ip> -request -outputfile roast.txt

• MITRE: T1558.003 (Steal or Forge Kerberos Tickets: Kerberoasting).
• Defender watch: 4769 with 0x17 for accounts that otherwise use AES; a single principal requesting many distinct SPN tickets in a short window.
• Remediation: strong (25+ char) service-account passwords or gMSA; AES-only on service accounts; monitor 4769 by encryption type.

AS-REP Roasting: Event 4768, no pre-auth

Cracking accounts that have Kerberos pre-authentication disabled, no valid credential needed to request the roastable material.

• Event 4768 (TGT requested) with Pre-Authentication Type = 0. Normal accounts always pre-authenticate; a 4768 with no pre-auth is the signature.
• MDI: "Suspected AS-REP Roasting attack."

GetNPUsers.py corp.local/ -usersfile users.txt -dc-ip <dc_ip> -no-pass -format hashcat

• MITRE: T1558.004 (AS-REP Roasting).
• Defender watch: 4768 with pre-auth type 0; any account carrying DONT_REQUIRE_PREAUTH.
• Remediation: remove DONT_REQUIRE_PREAUTH wherever possible; strong passwords on accounts that genuinely need it; alert on the flag being set.

DCSync: Event 4662, replication GUIDs

Replicating credentials out of the DC using directory-replication rights. High severity, never transparent, so coordinate before running.

• Event 4662 (operation on a directory object) with the replication rights GUIDs:
  • 1131f6aa-9c07-11d1-f79f-00c04fc2dcd2: DS-Replication-Get-Changes
  • 1131f6ad-9c07-11d1-f79f-00c04fc2dcd2: DS-Replication-Get-Changes-All
• MDI: "Suspected DCSync attack (replication of directory services)": a critical alert in any competent SOC.
• The source host in the DC logs is your machine's IP, not a real DC. That mismatch (a non-DC requesting replication) is itself the detection.

secretsdump.py corp.local/user:pass@dc01.corp.local -just-dc-user krbtgt

• MITRE: T1003.006 (OS Credential Dumping: DCSync).
• Defender watch: 4662 with the Get-Changes GUIDs from any principal that is not a DC; replication requests sourced from non-DC IPs.
• Remediation: audit and minimize who holds Get-Changes / Get-Changes-All; alert on replication from non-DC sources; tier-0 isolation.

LSASS dumping: blocked by EDR

Dumping process memory of lsass.exe to extract credentials.

• Modern EDR in blocking mode (CrowdStrike Falcon, SentinelOne, Defender for Endpoint) intercepts MiniDumpWriteDump against lsass. The result is a blocked/empty dump, a crashed process, or an immediate alert naming your tool.
• Event 4688 (process creation) plus EDR-specific handle-to-lsass telemetry.

Alternatives that avoid touching lsass live:

• SAM/SYSTEM/SECURITY registry hive dump (local admin) → offline parsing.
• DPAPI offline extraction.
• Volume Shadow Copy of the hive + offline parse.
• gMSA / LAPS fetch over LDAP (no endpoint touch at all).

# Registry-hive route: avoids a live lsass handle
secretsdump.py -sam sam.save -system system.save LOCAL

• MITRE: T1003.001 (LSASS Memory).
• Defender watch: process handles opened to lsass with read/VM-read access; EDR memory-access alerts.
• Remediation: Credential Guard; LSASS as a protected process (RunAsPPL); EDR in blocking mode.

BloodHound collection: a recognizable LDAP signature

• Collector queries have well-known shapes: (objectCategory=computer) pulling dozens of attributes, plus queries for msDS-AllowedToDelegateTo, delegation and ACL attributes in bulk.

• MDI and legacy ATA carry specific detection for BloodHound-style enumeration.

• Quieter collection requests only the attributes it needs (never *) and spreads queries over time instead of firing them all at connect.

• MITRE: T1087 (Account Discovery), T1069 (Permission Groups Discovery).

• Defender watch: a single principal issuing large attribute-heavy LDAP sweeps in a short window.