Detect Domain Controller Authentication in IBM QRadar
Adversaries may patch the authentication process on a domain controller to bypass typical authentication mechanisms and enable access to accounts. Malware such as Skeleton Key is injected into LSASS on a domain controller, allowing any user to authenticate with a hardcoded backdoor password. The patch persists only in memory and is erased upon reboot, making detection during active exploitation critical. Chimera group has used this technique to allow login without valid credentials.
MITRE ATT&CK
- Technique
- T1556 Modify Authentication Process
- Sub-technique
- T1556.001 Domain Controller Authentication
- Canonical reference
- https://attack.mitre.org/techniques/T1556/001/
QRadar Detection Query
SELECT
DATEFORMAT(starttime, 'yyyy-MM-dd HH:mm:ss') AS EventTime,
sourceip AS SourceHost,
username AS SourceUser,
"SourceImage",
"TargetImage",
"GrantedAccess",
"CommandLine",
QIDNAME(qid) AS EventName,
logsourcename(logsourceid) AS LogSource
FROM events
WHERE
LOGSOURCETYPENAME(devicetype) ILIKE '%Sysmon%'
AND (
(
"eventid" = '10'
AND "TargetImage" ILIKE '%\lsass.exe'
AND "SourceImage" NOT ILIKE '%\MsMpEng.exe'
AND "SourceImage" NOT ILIKE '%\csrss.exe'
AND "SourceImage" NOT ILIKE '%\werfault.exe'
AND "SourceImage" NOT ILIKE '%\taskmgr.exe'
AND "SourceImage" NOT ILIKE '%\services.exe'
AND "SourceImage" NOT ILIKE '%\lsm.exe'
AND "SourceImage" NOT ILIKE '%\svchost.exe'
AND "SourceImage" NOT ILIKE '%\winlogon.exe'
AND "GrantedAccess" IN ('0x1fffff', '0x1f3fff', '0x143a', '0x1010', '0x143A')
)
OR
(
"eventid" = '1'
AND (
LOWER("CommandLine") ILIKE '%misc::skeleton%'
OR LOWER("CommandLine") ILIKE '%skeleton key%'
OR LOWER("CommandLine") ILIKE '%skeletonkey%'
OR LOWER("CommandLine") ILIKE '%mimikatz%'
OR LOWER("CommandLine") ILIKE '%sekurlsa::pth%'
OR LOWER("CommandLine") ILIKE '%lsadump::lsa%'
)
)
)
ORDER BY starttime DESC
LAST 24 HOURSDetects Skeleton Key LSASS injection in IBM QRadar using AQL against Sysmon custom-extracted properties. Correlates Sysmon Event 10 (Process Access) with high-privilege GrantedAccess masks against lsass.exe excluding known-safe processes, and Event 1 (Process Create) with Mimikatz/Skeleton Key command-line strings. Requires QRadar DSM Editor custom properties configured to extract SourceImage, TargetImage, GrantedAccess, CommandLine, and eventid from Sysmon XML payloads.
Data Sources
Required Tables
False Positives & Tuning
- Custom property extraction for TargetImage and GrantedAccess in the QRadar DSM Editor may be inconsistent across different Sysmon schema versions; validate extraction rules against known LSASS accesses in a test environment before production deployment.
- Third-party security scanning products not in the NOT ILIKE exclusion list may generate high-volume false positives; run SELECT SourceImage, COUNT(*) FROM events WHERE TargetImage ILIKE '%\lsass.exe' GROUP BY SourceImage ORDER BY 2 DESC LAST 7 DAYS to inventory legitimate accessors before tuning.
- Inconsistent Sysmon deployment across domain controllers causes false negatives rather than false positives; verify Sysmon is deployed and forwarding on all DCs before treating alert absence as a safety signal.
Other platforms for T1556.001
Testing Methodology
Validate this detection against 3 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.
- Test 1Mimikatz Skeleton Key Injection (Simulated — Non-DC)
Expected signal: Sysmon Event ID 1: Process Create with Image=mimikatz.exe, CommandLine containing 'misc::skeleton'. Security Event ID 4688 with ProcessCommandLine=mimikatz.exe. If run with sufficient privilege, Sysmon Event ID 10 will show lsass.exe being accessed with high privilege mask.
- Test 2Suspicious LSASS Access via ProcDump
Expected signal: Sysmon Event ID 10: ProcessAccess with TargetImage=lsass.exe, SourceImage=procdump.exe, GrantedAccess=0x1fffff. Sysmon Event ID 11: FileCreate for the .dmp file. Security Event ID 4688 for procdump.exe process creation.
- Test 3LSASS Access via Task Manager (Low-Fidelity Baseline Test)
Expected signal: Sysmon Event ID 1: Process Create for powershell.exe with Get-Process lsass in CommandLine. PowerShell ScriptBlock Log Event ID 4104 with the script content. Security Event ID 4688 for powershell.exe.
References (7)
- https://attack.mitre.org/techniques/T1556/001/
- https://www.secureworks.com/research/skeleton-key-malware-analysis
- https://technet.microsoft.com/en-us/library/dn487457.aspx
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1556.001/T1556.001.md
- https://blog.gentilkiwi.com/securite/mimikatz/skeleton-key
- https://docs.microsoft.com/en-us/windows/security/identity-protection/credential-guard/credential-guard
- https://medium.com/threatpunter/detecting-attempts-to-steal-passwords-from-memory-558f16dce4ea
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