Detect Input Capture in Microsoft Sentinel
Adversaries may use methods of capturing user input to obtain credentials or collect information. During normal system usage, users often provide credentials to various different locations, such as login pages/portals or system dialog boxes. Input capture mechanisms may be transparent to the user (e.g. Credential API Hooking) or rely on deceiving the user into providing input into what they believe to be a genuine service (e.g. Web Portal Capture). Common sub-techniques include keylogging via Windows hooks (SetWindowsHookEx), GUI input capture via credential dialog spoofing, web portal capture via fake login pages, and credential API hooking via DLL injection into authentication processes. Threat actors including APT42, Storm-1811, and APT39 have leveraged these techniques, as have malware families such as InvisibleFerret, Chaes, Kobalos, and NPPSPY.
MITRE ATT&CK
- Tactic
- Collection Credential Access
- Technique
- T1056 Input Capture
- Canonical reference
- https://attack.mitre.org/techniques/T1056/
KQL Detection Query
// T1056 Input Capture — Multi-Signal Detection
// Covers: Network Provider DLL registration (NPPSPY), suspicious DLL loads into credential processes,
// input hook API usage, and clipboard/keyboard monitoring process activity
let SuspiciousInputAPIs = dynamic([
"SetWindowsHookEx", "GetAsyncKeyState", "GetKeyState", "GetRawInputData",
"pyWinhook", "pynput", "keyboard.hook", "InputCapture",
"WH_KEYBOARD", "WH_KEYBOARD_LL", "WH_MOUSE_LL"
]);
let CredentialProcesses = dynamic(["winlogon.exe", "lsass.exe", "LogonUI.exe", "consent.exe", "credui.exe"]);
// Signal 1: Suspicious network provider DLL registration (NPPSPY technique)
let NetworkProviderReg = DeviceRegistryEvents
| where Timestamp > ago(24h)
| where ActionType in ("RegistryValueSet", "RegistryKeyCreated")
| where RegistryKey has @"SYSTEM\CurrentControlSet\Control\NetworkProvider\Order"
or (RegistryKey has @"SYSTEM\CurrentControlSet\Services" and RegistryKey endswith @"\NetworkProvider")
| where InitiatingProcessFileName !in~ ("services.exe", "svchost.exe", "msiexec.exe", "TrustedInstaller.exe")
| extend SignalType = "NetworkProviderRegistration"
| project Timestamp, DeviceName, AccountName, SignalType,
RegistryKey, RegistryValueName, RegistryValueData,
InitiatingProcessFileName, InitiatingProcessCommandLine, InitiatingProcessFolderPath;
// Signal 2: Suspicious DLL loaded into credential/authentication processes
let HookDLLLoad = DeviceImageLoadEvents
| where Timestamp > ago(24h)
| where InitiatingProcessFileName in~ (CredentialProcesses)
| where FolderPath !startswith @"C:\Windows\System32\\"
and FolderPath !startswith @"C:\Windows\SysWOW64\\"
and FolderPath !startswith @"C:\Program Files\\"
and FolderPath !startswith @"C:\Program Files (x86)\\"
| where FileName endswith ".dll"
| extend SignalType = "SuspiciousDLLInCredentialProcess"
| project Timestamp, DeviceName, AccountName=InitiatingProcessAccountName, SignalType,
FileName, FolderPath, SHA256,
InitiatingProcessFileName, InitiatingProcessCommandLine, InitiatingProcessFolderPath;
// Signal 3: Process creation with input capture indicators
let InputCaptureProcess = DeviceProcessEvents
| where Timestamp > ago(24h)
| where ProcessCommandLine has_any (SuspiciousInputAPIs)
or (FileName has_any ("keylog", "keyscan", "hookdll", "inputcap", "credcap"))
or (FolderPath !startswith @"C:\Windows\" and FolderPath !startswith @"C:\Program Files"
and (ProcessCommandLine has "GetClipboard" or ProcessCommandLine has "Get-Clipboard")
and ProcessCommandLine has_any ("while", "loop", "sleep", "timer", "interval"))
| extend SignalType = "InputCaptureAPIOrTool"
| project Timestamp, DeviceName, AccountName, SignalType,
FileName, FolderPath, ProcessCommandLine,
InitiatingProcessFileName, InitiatingProcessCommandLine, InitiatingProcessFolderPath;
// Signal 4: Process injection into Winlogon or credential UI (common for hooking)
let WinlogonInjection = DeviceEvents
| where Timestamp > ago(24h)
| where ActionType == "CreateRemoteThreadApiCall" or ActionType == "ProcessInjection"
| where AdditionalFields has_any ("winlogon.exe", "LogonUI.exe", "credui.exe", "consent.exe")
| extend SignalType = "InjectionIntoCredentialProcess"
| project Timestamp, DeviceName, AccountName, SignalType,
FileName, ProcessCommandLine=AdditionalFields,
InitiatingProcessFileName, InitiatingProcessCommandLine, InitiatingProcessFolderPath;
// Union all signals
union isfuzzy=true NetworkProviderReg, HookDLLLoad, InputCaptureProcess, WinlogonInjection
| sort by Timestamp descMulti-signal detection for T1056 Input Capture covering four distinct attack patterns: (1) malicious network provider DLL registration (NPPSPY technique intercepts Winlogon credentials), (2) unsigned/unexpected DLL loads into credential and authentication processes (winlogon, LogonUI, lsass), (3) process creation with known input capture APIs or tool naming patterns including clipboard monitoring loops, and (4) process injection into credential management processes. Uses DeviceRegistryEvents, DeviceImageLoadEvents, DeviceProcessEvents, and DeviceEvents tables from Microsoft Defender for Endpoint.
Data Sources
Required Tables
False Positives & Tuning
- Legitimate accessibility software (screen readers, on-screen keyboards, Dragon NaturallySpeaking) that register low-level keyboard hooks via SetWindowsHookEx
- Enterprise security products (DLP agents, PAM tools like CyberArk) that monitor credential entry as a security control — these load DLLs into credential processes
- Password managers (1Password, Bitwarden, KeePass) that hook input fields for autofill functionality
- Keyboard remapping utilities (AutoHotkey, SharpKeys, Microsoft PowerToys) that legitimately intercept and redirect keystrokes
- Remote desktop and KVM software (TeamViewer, AnyDesk, VNC) that capture keyboard/mouse input for remote transmission
- Custom enterprise single-sign-on (SSO) credential providers legitimately registered as network providers in HKLM\SYSTEM\CurrentControlSet\Control\NetworkProvider\Order
Other platforms for T1056
Testing Methodology
Validate this detection against 5 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 1NPPSPY Network Provider Registration (Credential Interception Setup)
Expected signal: Sysmon Event ID 12 (RegistryKeyCreate): TargetObject containing HKLM\SYSTEM\CurrentControlSet\Services\TestNPP. Sysmon Event ID 13 (RegistryValueSet): TargetObject containing NetworkProvider\Order with Details showing 'TestNPP' appended to ProviderOrder. Security Event ID 4657 (Registry value modification) if object access auditing is enabled. MDE DeviceRegistryEvents with ActionType=RegistryKeyCreated and RegistryKeyCreated for both the service key and NetworkProvider\Order.
- Test 2Low-Level Keyboard Hook via PowerShell PInvoke (SetWindowsHookEx WH_KEYBOARD_LL)
Expected signal: Sysmon Event ID 1: Process Create with Image=powershell.exe, CommandLine containing 'SetWindowsHookEx', 'WH_KEYBOARD_LL' or value '13', and 'Add-Type'. PowerShell ScriptBlock Log Event ID 4104 with the full PInvoke code including SetWindowsHookEx. MDE DeviceProcessEvents with ProcessCommandLine matching SetWindowsHookEx pattern.
- Test 3Clipboard Monitoring Loop with File Exfiltration Simulation
Expected signal: Sysmon Event ID 1: Process Create with Image=powershell.exe, CommandLine containing 'Get-Clipboard', 'while', 'Start-Sleep', 'Add-Content', '-WindowStyle Hidden'. Sysmon Event ID 11 (File Create): cb_harvest.txt created in %TEMP%. MDE DeviceProcessEvents with ProcessCommandLine matching clipboard + loop pattern. MDE DeviceFileEvents showing file writes to TEMP directory.
- Test 4SSH Client Trojanization Simulation (Kobalos Pattern — Linux)
Expected signal: Auditd: file modification events on /usr/bin/ssh binary (syscall=rename or write). Syslog: file integrity monitoring alerts if AIDE/Tripwire/OSSEC is configured. If Linux auditd with file watches configured: SYSCALL records for rename/unlink on /usr/bin/ssh. Process execution telemetry showing /usr/bin/ssh spawning /tmp/ssh_real as child process. File creation event for /tmp/.ssh_capture.log.
- Test 5Python Keylogger via pynput (Cross-Platform)
Expected signal: Sysmon Event ID 1: Process Create for pip.exe (pynput installation) and python.exe (keylogger execution). CommandLine of python.exe containing 'pynput', 'keyboard', 'Listener', 'on_press'. Sysmon Event ID 7: Image loads for pynput DLL dependencies into python.exe. Network connection (Sysmon Event ID 3) from pip.exe to PyPI for package download during installation phase. MDE DeviceProcessEvents capturing both pip and python command lines.
References (14)
- https://attack.mitre.org/techniques/T1056/
- https://attack.mitre.org/techniques/T1056/001/
- https://attack.mitre.org/techniques/T1056/002/
- https://attack.mitre.org/techniques/T1056/003/
- https://attack.mitre.org/techniques/T1056/004/
- https://www.huntress.com/blog/credential-interception-via-nppspy
- https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setwindowshookexw
- https://www.welivesecurity.com/2021/01/26/kobalos-complex-linux-threat-high-performance-computing-infrastructure/
- https://unit42.paloaltonetworks.com/contagious-interview-beavertail-invisibleferret/
- https://www.sentinelone.com/labs/metador-technical-appendix/
- https://www.cybereason.com/blog/research/chaes-hunting-the-prey
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1056.001/T1056.001.md
- https://github.com/SigmaHQ/sigma/blob/master/rules/windows/registry/registry_set/registry_set_credentials_stealing_via_network_provider.yml
- http://opensecuritytraining.info/Keylogging_files/The%20Adventures%20of%20a%20Keystroke.pdf
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