Detect Token Impersonation/Theft in CrowdStrike LogScale
Adversaries may duplicate then impersonate another user's existing token to escalate privileges and bypass access controls. DuplicateToken or DuplicateTokenEx are used to clone an existing process token, which is then applied to the current thread via ImpersonateLoggedOnUser or SetThreadToken, or used to create a new process via CreateProcessWithTokenW. This allows an adversary to operate under a different security context — typically a higher-privileged user — without needing that user's credentials. Token theft is commonly performed against LSASS, winlogon, explorer.exe, or other processes running as privileged users, and is a core capability of post-exploitation frameworks including Cobalt Strike (steal_token), Metasploit (incognito), Havoc, SILENTTRINITY, and Pupy. Real-world actors including APT28, Emotet, REvil, Tarrask, and FinFisher have all leveraged this technique.
MITRE ATT&CK
- Technique
- T1134 Access Token Manipulation
- Sub-technique
- T1134.001 Token Impersonation/Theft
- Canonical reference
- https://attack.mitre.org/techniques/T1134/001/
LogScale Detection Query
#event_simpleName in ("ProcessRollup2", "ProcessAccessV2", "ProcessAccess")
| case {
/* Branch 1: ProcessAccessV2 — handle acquisition to privileged Windows processes with token-theft access masks */
#event_simpleName in ("ProcessAccessV2", "ProcessAccess")
TargetImageFileName = /(?i)(\\lsass\.exe|\\winlogon\.exe|\\csrss\.exe|\\services\.exe|\\wininit\.exe)$/
GrantedAccess = /^(0x1010|0x1fffff|0x1f0fff|0x143a|0x0040|0x40|0x1410|0x0002|0x0004)$/i
NOT SourceImageFileName = /(?i)(\\MsMpEng\.exe|\\SenseIR\.exe|\\SenseCE\.exe|\\SecurityHealthService\.exe|\\csrss\.exe|\\smss\.exe|\\wininit\.exe|\\AzureADConnectAuthenticatio\.exe)$/
| eval Branch := "ProcessAccess_PrivTarget"
| eval RiskScore := 70;
/* Branch 2: ProcessRollup2 — token manipulation tool execution or C2 post-exploitation CLI patterns */
#event_simpleName = "ProcessRollup2"
(
ImageFileName = /(?i)(\\incognito\.exe|\\tokenvator\.exe|\\tokenduplicator\.exe|\\token_manipulator\.exe)$/
OR CommandLine = /(?i)(steal_token|impersonate_token|Invoke-TokenManipulation|ImpersonateLoggedOnUser|DuplicateTokenEx|SetThreadToken|getsystem|rev2self|NtFilterToken|SeImpersonatePrivilege)/
)
| eval Branch := "TokenManip_Tool"
| eval RiskScore := 85;
* | drop;
}
| eval TargetProc := TargetImageFileName
| eval SourceProc := coalesce(SourceImageFileName, ImageFileName)
| table([@timestamp, ComputerName, UserName, SourceProc, TargetProc, GrantedAccess, CommandLine, Branch, RiskScore])
| sort(RiskScore, order=desc, limit=1000)Two-branch CrowdStrike Falcon LogScale detection for T1134.001 using native Falcon telemetry events. Branch 1 queries ProcessAccessV2/ProcessAccess events for handle acquisition targeting LSASS, winlogon, csrss, services, and wininit with access masks associated with token duplication (TOKEN_DUPLICATE 0x0002, PROCESS_DUP_HANDLE 0x0040, mimikatz-style 0x1010, C2 combo mask 0x143a), filtering out known legitimate security product source images. Branch 2 queries ProcessRollup2 for execution of known token theft tool binaries (incognito, tokenvator, tokenduplicator) and command-line patterns from Cobalt Strike (steal_token, rev2self, getsystem), Metasploit (impersonate_token), and PowerSploit (Invoke-TokenManipulation, ImpersonateLoggedOnUser, DuplicateTokenEx). An additional hunting query surfaces Windows API call references in command lines for proactive threat hunting.
Data Sources
Required Tables
False Positives & Tuning
- The CrowdStrike Falcon sensor itself may generate ProcessAccessV2 events when inspecting LSASS for threat detection — Falcon-internal sensor processes may not be captured in SourceImageFileName and could appear as unnamed or system-context accessors requiring exclusion by PID lineage
- Privileged Access Management solutions (CyberArk Endpoint Privilege Manager, BeyondTrust PowerBroker) that perform just-in-time token elevation to grant temporary SYSTEM access will trigger Branch 1 with legitimate access mask patterns — identify by correlating with PAM session context or known PAM agent process names
- Enterprise PowerShell automation frameworks (PSRemoting runspaces, SCOM management agents) that reference token API names as strings in script bodies or error handling code may match Branch 2 CommandLine regex without executing actual token operations
Other platforms for T1134.001
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 1DuplicateToken API Call via PowerShell P/Invoke (Self-Token)
Expected signal: Sysmon Event ID 1: Process Create for powershell.exe with CommandLine containing 'TokenDup', 'DuplicateToken', 'OpenProcessToken'. Sysmon Event ID 7 (ImageLoad): advapi32.dll and kernel32.dll loaded by powershell.exe. PowerShell ScriptBlock Log Event ID 4104 with the full Add-Type block showing DllImport declarations for advapi32.dll token APIs.
- Test 2LSASS Process Handle Acquisition (Sysmon EventID 10 Trigger)
Expected signal: Sysmon Event ID 10 (ProcessAccess): SourceImage=powershell.exe, TargetImage=C:\Windows\System32\lsass.exe, GrantedAccess=0x0400, CallTrace will show the call chain through ntdll.dll → kernel32.dll → the powershell.exe process. This is the primary detection event. Security Event ID 4656 (Handle request) may also appear if object access auditing is enabled.
- Test 3ImpersonateLoggedOnUser on Current Process Token
Expected signal: Sysmon Event ID 1: Process Create for powershell.exe with CommandLine containing 'ImpersonateLoggedOnUser', 'RevertToSelf', 'TokenImp'. PowerShell ScriptBlock Log Event ID 4104 with the full P/Invoke block showing advapi32.dll imports for impersonation APIs. Security Event ID 4672 may fire if the token carries elevated privileges.
- Test 4Invoke-TokenManipulation Enumeration via PowerSploit
Expected signal: Sysmon Event ID 1: powershell.exe process with CommandLine containing 'Invoke-TokenManipulation' and '-Enumerate'. Sysmon Event ID 3: Network connection from powershell.exe to raw.githubusercontent.com on port 443 (for the download). Sysmon Event ID 11: File created at %TEMP%\InvTokMnp.ps1. PowerShell ScriptBlock Log Event ID 4104: multiple events showing the Invoke-TokenManipulation module code and the -Enumerate call. Security Event ID 4672 if the enumeration surfaces elevated token contexts.
References (9)
- https://attack.mitre.org/techniques/T1134/001/
- https://learn.microsoft.com/en-us/windows/win32/api/securitybaseapi/nf-securitybaseapi-duplicatetoken
- https://learn.microsoft.com/en-us/windows/win32/api/securitybaseapi/nf-securitybaseapi-duplicatetokenex
- https://learn.microsoft.com/en-us/windows/win32/api/securitybaseapi/nf-securitybaseapi-impersonateloggedonuser
- https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-setthreadtoken
- https://github.com/PowerShellMafia/PowerSploit/blob/master/Exfiltration/Invoke-TokenManipulation.ps1
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1134.001/T1134.001.md
- https://posts.specterops.io/understanding-and-defending-against-access-token-manipulation-ef7d9fa67d50
- https://learn.microsoft.com/en-us/sysinternals/downloads/sysmon
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