Agent Skills: Detecting T1003 Credential Dumping with EDR

Detecting T1003 Credential Dumping with EDR

When to Use

• When hunting for credential theft activity in the environment
• After compromise indicators suggest attacker has elevated privileges
• When EDR alerts fire for LSASS access or suspicious process memory reads
• During incident response to determine scope of credential compromise
• When auditing LSASS protection controls (Credential Guard, RunAsPPL)

Prerequisites

• EDR agent deployed with LSASS access monitoring (CrowdStrike, Defender for Endpoint, SentinelOne)
• Sysmon Event ID 10 (ProcessAccess) with LSASS-specific filters
• Windows Security Event ID 4656/4663 (Object Access Auditing)
• LSASS SACL auditing enabled (Windows 10+)
• Registry auditing for SAM hive access

Workflow

1. Monitor LSASS Process Access: Track all processes opening handles to lsass.exe with suspicious access rights (PROCESS_VM_READ 0x0010, PROCESS_ALL_ACCESS 0x1FFFFF). Non-privileged or unusual processes accessing LSASS are strong indicators.
2. Detect Credential Dumping Tools: Hunt for known tool signatures -- Mimikatz (sekurlsa::logonpasswords), procdump.exe targeting LSASS, comsvcs.dll MiniDump, and Task Manager creating LSASS dumps.
3. Monitor NTDS.dit Access: Detect Volume Shadow Copy creation (vssadmin, wmic shadowcopy) followed by NTDS.dit file access, or ntdsutil.exe IFM creation.
4. Track SAM/SECURITY/SYSTEM Hive Access: Hunt for reg.exe save commands targeting SAM, SECURITY, and SYSTEM registry hives.
5. Detect DCSync Activity: Monitor for non-DC accounts requesting directory replication (Event 4662 with replication GUIDs).
6. Correlate with Lateral Movement: After credential dumping, attackers typically move laterally. Correlate credential access events with subsequent remote logon attempts.
7. Assess Impact: Determine which credentials were potentially compromised and initiate password resets.

Key Concepts

| Concept | Description | |---------|-------------| | T1003.001 | LSASS Memory -- dumping credentials from LSASS process | | T1003.002 | Security Account Manager -- extracting local account hashes from SAM | | T1003.003 | NTDS -- extracting domain hashes from Active Directory database | | T1003.004 | LSA Secrets -- extracting service account passwords | | T1003.005 | Cached Domain Credentials -- extracting DCC2 hashes | | T1003.006 | DCSync -- replicating credentials from domain controller | | Credential Guard | Virtualization-based isolation of LSASS secrets | | RunAsPPL | Protected Process Light for LSASS |

Detection Queries

Splunk -- LSASS Access Detection

index=sysmon EventCode=10
| where match(TargetImage, "(?i)lsass\.exe$")
| where GrantedAccess IN ("0x1FFFFF", "0x1F3FFF", "0x143A", "0x1F0FFF", "0x0040", "0x1010", "0x1410")
| where NOT match(SourceImage, "(?i)(csrss|lsass|svchost|MsMpEng|WmiPrvSE|taskmgr|procexp|SecurityHealthService)\.exe$")
| table _time Computer SourceImage SourceProcessId GrantedAccess CallTrace

Splunk -- Credential Dumping Tool Detection

index=sysmon EventCode=1
| where match(CommandLine, "(?i)(sekurlsa|lsadump|kerberos::list|crypto::certificates)")
    OR match(CommandLine, "(?i)procdump.*-ma.*lsass")
    OR match(CommandLine, "(?i)comsvcs\.dll.*MiniDump")
    OR match(CommandLine, "(?i)ntdsutil.*\"ac i ntds\".*ifm")
    OR match(CommandLine, "(?i)reg\s+save\s+hklm\\\\(sam|security|system)")
    OR match(CommandLine, "(?i)vssadmin.*create\s+shadow")
| table _time Computer User Image CommandLine ParentImage

KQL -- Microsoft Defender for Endpoint

DeviceEvents
| where Timestamp > ago(7d)
| where ActionType in ("LsassAccess", "CredentialDumpingActivity")
| project Timestamp, DeviceName, AccountName, InitiatingProcessFileName,
    InitiatingProcessCommandLine, ActionType, AdditionalFields
| sort by Timestamp desc

Sigma Rule -- LSASS Credential Dumping

title: LSASS Memory Credential Dumping Attempt
status: stable
logsource:
    product: windows
    category: process_access
detection:
    selection:
        TargetImage|endswith: '\lsass.exe'
        GrantedAccess|contains:
            - '0x1FFFFF'
            - '0x1F3FFF'
            - '0x143A'
            - '0x0040'
    filter:
        SourceImage|endswith:
            - '\csrss.exe'
            - '\lsass.exe'
            - '\MsMpEng.exe'
            - '\svchost.exe'
    condition: selection and not filter
level: critical
tags:
    - attack.credential_access
    - attack.t1003.001

Common Scenarios

1. Mimikatz sekurlsa: Direct LSASS memory reading via sekurlsa::logonpasswords to extract plaintext passwords, NTLM hashes, and Kerberos tickets.
2. ProcDump LSASS: procdump.exe -ma lsass.exe lsass.dmp creating a memory dump for offline credential extraction.
3. Comsvcs.dll MiniDump: rundll32.exe comsvcs.dll MiniDump [LSASS_PID] dump.bin full using a built-in Windows DLL for LSASS dumping.
4. NTDS.dit Extraction: Creating a Volume Shadow Copy and copying NTDS.dit + SYSTEM hive for offline domain hash extraction with secretsdump.
5. SAM Hive Export: reg save HKLM\SAM sam.save followed by reg save HKLM\SYSTEM system.save for local account hash extraction.
6. Task Manager Dump: Right-clicking LSASS in Task Manager to create a memory dump -- a legitimate tool abused for credential theft.

Output Format

Hunt ID: TH-CRED-[DATE]-[SEQ]
Host: [Hostname]
Dumping Method: [LSASS_Access/NTDS/SAM/DCSync]
Source Process: [Tool or process used]
Target: [LSASS/NTDS.dit/SAM/SECURITY]
Access Rights: [Granted access mask]
User Context: [Account performing the dump]
ATT&CK Technique: [T1003.00x]
Risk Level: [Critical/High/Medium]
Credentials at Risk: [Scope assessment]