Which SIEM platforms have a T1556 detection rule?

df00tech provides T1556 (Modify Authentication Process) detection queries for 7 SIEM platforms: Microsoft Sentinel / Defender, Splunk, Elastic Security (EQL), IBM QRadar (AQL), Sumo Logic CSE, Google Chronicle / SecOps, CrowdStrike LogScale (CQL).

What severity and confidence is the T1556 detection?

The T1556 detection is rated critical severity with high confidence.

What are common false positives for T1556?

Common false positives for T1556 include: Legitimate MFA solutions (Duo Security, Okta Verify, RSA SecurID) that install custom credential provider DLLs during initial setup — filter by InitiatingProcessFileName = msiexec.exe and correlate with change management tickets; Enterprise privileged access management tools (CyberArk, BeyondTrust, Centrify) that register authentication packages — build an allowlist of their specific DLL names; Windows Defender Credential Guard enabling LSA protection, which modifies LSA configuration keys — these changes come from svchost.exe or TrustedInstaller.

T1556 Microsoft Sentinel · KQL

Detect Modify Authentication Process in Microsoft Sentinel

Q: What data sources are required to detect Modify Authentication Process (T1556)?

Detecting Modify Authentication Process requires the following data sources: Registry: Registry Key Modification, Module: Module Load, Process: Process Creation, Microsoft Defender for Endpoint.

Adversaries may modify authentication mechanisms and processes to access user credentials or enable otherwise unwarranted access to accounts. The authentication process is handled by mechanisms such as the Local Security Authentication Server (LSASS) process and the Security Accounts Manager (SAM) on Windows, pluggable authentication modules (PAM) on Unix-based systems, and authorization plugins on macOS systems. By modifying an authentication process, an adversary may authenticate to a service or system without using valid accounts, or may passively harvest credentials as users authenticate. Techniques include registering malicious password filter DLLs that receive plaintext passwords during every password change, injecting security support providers (SSPs) into LSASS to intercept credentials, installing skeleton keys to accept any password for domain accounts, modifying PAM stack configuration files to permit unauthorized access, and replacing legitimate authentication binaries with trojanized versions that exfiltrate credentials.

MITRE ATT&CK

Tactic: Credential Access Defense Evasion Persistence
Technique: T1556 Modify Authentication Process
Canonical reference: https://attack.mitre.org/techniques/T1556/

KQL Detection Query

Microsoft Sentinel (KQL)

kusto

// T1556: Modify Authentication Process
// Detects modifications to Windows LSA authentication registry keys used to register
// password filter DLLs, SSPs, auth packages, network providers, and GINA DLLs.
// These are the primary persistence paths for credential interception malware
// such as skeleton key (Secureworks), Ebury, Kessel, and SILENTTRINITY.
let LsaRegistryPaths = dynamic([
    "CurrentControlSet\\Control\\Lsa\\Notification Packages",
    "CurrentControlSet\\Control\\Lsa\\Security Packages",
    "CurrentControlSet\\Control\\Lsa\\Authentication Packages",
    "CurrentControlSet\\Control\\Lsa\\OSConfig\\Security Packages",
    "CurrentControlSet\\Control\\NetworkProvider\\Order",
    "CurrentVersion\\Winlogon\\GinaDLL",
    "CurrentVersion\\Authentication\\Credential Providers"
]);
let TrustedModifiers = dynamic([
    "TrustedInstaller.exe", "MsMpEng.exe", "msiexec.exe",
    "wuauclt.exe", "WindowsUpdateAgent.exe", "svchost.exe"
]);
let LsaLoadEvents = DeviceImageLoadEvents
| where Timestamp > ago(24h)
| where InitiatingProcessFileName =~ "lsass.exe"
| where not(FileName in~ (
    "ntdll.dll", "kernel32.dll", "kernelbase.dll", "msvcrt.dll",
    "kerberos.dll", "msv1_0.dll", "wdigest.dll", "tspkg.dll",
    "pku2u.dll", "cloudap.dll", "schannel.dll", "cryptdll.dll",
    "samsrv.dll", "lsasrv.dll", "netlogon.dll", "ntlmshared.dll"
))
| extend DetectionSource = "LsassUnexpectedDllLoad"
| project Timestamp, DeviceName, AccountName = InitiatingProcessAccountName,
          DetectionType = "Unexpected DLL Load by LSASS",
          RegistryKey = "", RegistryValueName = "", RegistryValueData = "",
          DllName = FileName, DllPath = FolderPath, SHA256,
          InitiatingProcessFileName, InitiatingProcessCommandLine;
let RegistryMods = DeviceRegistryEvents
| where Timestamp > ago(24h)
| where RegistryKey has_any (LsaRegistryPaths)
| where ActionType in ("RegistryValueSet", "RegistryKeyCreated")
| where not(InitiatingProcessFileName has_any (TrustedModifiers))
| extend DetectionType = case(
    RegistryKey has "Notification Packages", "Password Filter DLL Registration",
    RegistryKey has "Security Packages" and not (RegistryKey has "OSConfig"), "Security Support Provider (SSP) Registration",
    RegistryKey has "Authentication Packages", "Authentication Package Registration",
    RegistryKey has "NetworkProvider", "Network Provider DLL Registration",
    RegistryKey has "GinaDLL", "GINA DLL Modification",
    RegistryKey has "Credential Providers", "Credential Provider Registration",
    "LSA Authentication Configuration Modification"
)
| project Timestamp, DeviceName, AccountName, DetectionType,
          RegistryKey, RegistryValueName, RegistryValueData,
          DllName = "", DllPath = "", SHA256 = "",
          InitiatingProcessFileName, InitiatingProcessCommandLine;
RegistryMods
| union LsaLoadEvents
| extend IsDomainController = DeviceName has_any ("DC", "PDC", "BDC", "RODC")
| sort by Timestamp desc

critical severity high confidence

Detects modifications to Windows LSA authentication configuration by monitoring two key signals: (1) registry writes to authentication-critical keys including LSA Notification Packages (password filters), Security Packages (SSPs), Authentication Packages, Network Provider Order, and GINA DLL paths, excluding known-good Windows system processes; and (2) unexpected DLL loads by the lsass.exe process from non-standard DLL names not part of the default Windows authentication package list. Together these cover the primary persistence mechanisms used by skeleton key malware, Ebury, Kessel, and SILENTTRINITY to intercept credentials. Domain controller detections are flagged separately given their elevated impact.

Data Sources

Registry: Registry Key ModificationModule: Module LoadProcess: Process CreationMicrosoft Defender for Endpoint

Required Tables

DeviceRegistryEventsDeviceImageLoadEvents

False Positives & Tuning

Legitimate MFA solutions (Duo Security, Okta Verify, RSA SecurID) that install custom credential provider DLLs during initial setup — filter by InitiatingProcessFileName = msiexec.exe and correlate with change management tickets
Enterprise privileged access management tools (CyberArk, BeyondTrust, Centrify) that register authentication packages — build an allowlist of their specific DLL names
Windows Defender Credential Guard enabling LSA protection, which modifies LSA configuration keys — these changes come from svchost.exe or TrustedInstaller
Third-party VPN clients and smart card middleware that install network provider DLLs or credential providers as part of software installation
Password manager enterprise editions (LastPass Enterprise, 1Password Business) installing Windows credential provider extensions

Download portable Sigma rule (.yml)

Other platforms for T1556

Splunk (SPL) Elastic Security (Elastic) IBM QRadar (QRadar) Sumo Logic CSE (Sumo) Google Chronicle (YARA-L) CrowdStrike LogScale (LogScale) All platforms (combined) →

Testing Methodology

Validate this detection against 4 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 1Register Benign Password Filter DLL in LSA Notification Packages
Expected signal: Sysmon Event ID 13: TargetObject=HKLM\SYSTEM\CurrentControlSet\Control\Lsa\Notification Packages, Details contains 'df00tech-test-filter', Image=powershell.exe. Windows Security Event ID 4657 if SACL is configured on the LSA key. DeviceRegistryEvents in MDE: RegistryKey contains 'Notification Packages', RegistryValueData contains new DLL name, InitiatingProcessFileName=powershell.exe.
Test 2Register Fake Security Support Provider (SSP) in LSA Security Packages
Expected signal: Sysmon Event ID 13: TargetObject=HKLM\SYSTEM\CurrentControlSet\Control\Lsa\Security Packages, Details appended with 'df00tech-test-ssp'. DeviceRegistryEvents: RegistryKey contains 'Security Packages', ActionType=RegistryValueSet. If system reboots, Security Event ID 4610 will fire listing the (missing) SSP DLL name — LSASS will generate an error in System event log.
Test 3Modify PAM Configuration to Permit Authentication Bypass on Linux
Expected signal: Linux auditd: syscall=openat/write on path=/etc/pam.d/sshd with auid=<attacker_uid> if auditd watches are configured (-w /etc/pam.d/ -p wa -k pam_modification). Syslog: process writing to /etc/pam.d/sshd. File integrity monitoring (AIDE, Tripwire) will alert on hash change to /etc/pam.d/sshd. DeviceFileEvents (for Linux onboarded to MDE): FileModified on /etc/pam.d/sshd.
Test 4Register Malicious Network Provider DLL via Registry
Expected signal: Sysmon Event ID 13: TargetObject=HKLM\SYSTEM\CurrentControlSet\Control\NetworkProvider\Order\ProviderOrder, Image=powershell.exe, Details contains appended provider name. DeviceRegistryEvents: RegistryKey contains 'NetworkProvider\Order', RegistryValueName='ProviderOrder', ActionType=RegistryValueSet.

Last updated: 2026-04-13 Research depth: deep

References (9)

Response Playbook

1. Examine the full command line and decode any Base64 content...
2. Identify the parent process chain and user context...
3. Check for concurrent network connections from the process...

Investigation Guide

Related techniques: T1027, T1105, T1562.001...
Forensic artifacts: PSReadLine history, Prefetch, ScriptBlock logs...

Atomic Red Team Tests

Test 1: Encoded command execution...
Test 2: Download cradle via Net.WebClient...

Unlock Pro Content

Get the full detection package for T1556 including response playbook, investigation guide, and atomic red team tests.

Response PlaybookInvestigation GuideHunting QueriesAtomic Red Team TestsTuning Guidance

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Sub-techniques (9)

Related Techniques

T1556.001Domain Controller Authentication T1556.002Password Filter DLL T1556.003Pluggable Authentication Modules T1556.004Network Device Authentication T1556.008Network Provider DLL T1003OS Credential Dumping T1547.005Security Support Provider T1574Hijack Execution Flow T1078Valid Accounts T1543Create or Modify System Process

Detect Modify Authentication Process in Microsoft Sentinel

MITRE ATT&CK

KQL Detection Query

Data Sources

Required Tables

False Positives & Tuning

Other platforms for T1556

Testing Methodology

Response Playbook

Investigation Guide

Atomic Red Team Tests

Unlock Pro Content

Related Detections

Sub-techniques (9)

Related Techniques

Same Tactic: Credential Access

Popular Detections

MITRE ATT&CK

KQL Detection Query

Data Sources

Required Tables

False Positives & Tuning

Other platforms for T1556

Testing Methodology

Unlock Pro Content

Related Detections

Sub-techniques (9)

Related Techniques

Same Tactic: Credential Access

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