>Findstr.exe
Write to ADS, discover, or download files with Findstr.exe
Default Executable Paths
C:\Windows\System32\findstr.exeC:\Windows\SysWOW64\findstr.exeIntegrity & Metadata
Documented in LOLBAS project by Oddvar Moe.
Monitor process creation events where FileName is "Findstr.exe" or command line references known attack arguments.
Executive Summary & AI Quick Reference
Findstr.exe is a native utility pre-installed on Windows systems. Threat actors and red teams abuse Findstr.exe as a Living-off-the-Land Binary (LOLBin) to achieve Defense Evasion, Credential Dump, Download without triggering traditional antivirus file-hash alerts. Legitimate system administrators use it for routine administration, making behavioral command-line telemetry essential for differentiation.
Weaponized Parameters & Proof-of-Concepts
Documented attack commands, parameter flags, and privilege prerequisites.
Searches for the string W3AllLov3LolBas, since it does not exist (/V) the specified .exe file is written to an Alternate Data Stream (ADS) of the specified target file.
findstr /V /L W3AllLov3LolBas {PATH_ABSOLUTE:.exe} > {PATH_ABSOLUTE}:file.exeSearches for the string W3AllLov3LolBas, since it does not exist (/V) file.exe is written to an Alternate Data Stream (ADS) of the file.txt file.
findstr /V /L W3AllLov3LolBas {PATH_SMB:.exe} > {PATH_ABSOLUTE}:file.exeSearch for stored password in Group Policy files stored on SYSVOL.
findstr /S /I cpassword \\sysvol\policies\*.xmlSearches for the string W3AllLov3LolBas, since it does not exist (/V) file.exe is downloaded to the target file.
findstr /V /L W3AllLov3LolBas {PATH_SMB:.exe} > {PATH_ABSOLUTE:.exe}SIEM & EDR Detection Rules
Production telemetry rules configured for Microsoft Defender, Sigma, and Splunk.
Telemetry & SIEM Detection Suite (Findstr.exe)
Validated against MITRE T1564.004, T1552.001, T11051// Microsoft Defender XDR / Microsoft Sentinel2// Tactic: Defense Evasion3DeviceProcessEvents4| where FileName =~ "Findstr.exe"5| where ProcessCommandLine has_any ("Findstr")6| project7 Timestamp,8 DeviceName,9 AccountName,10 InitiatingProcessParentFileName,11 InitiatingProcessFileName,12 InitiatingProcessCommandLine,13 FileName,14 FolderPath,15 ProcessCommandLine,16 MD5,17 SHA25618| sort by Timestamp descMitigation, Hardening & Prevention
Recommended defensive controls to block or constrain Findstr.exe abuse.
Enforce Windows Defender Application Control (WDAC) or AppLocker publisher rules to prevent execution outside approved enterprise administration scripts.
Enable ASR rules: Block executable content from email client and webmail and Block Office applications from creating child processes spawning Findstr.exe.
Deploy the KQL, Sigma, and Splunk detection queries below. Alert on anomalous child processes, web requests to unrated external IPs, or encoded payload strings.
Frequently Asked Questions (FAQ) • Findstr.exe
Key operational questions and defensive answers about Findstr.exe LOLBin tradecraft.
What is Findstr.exe and why is it classified as a LOLBin?
Findstr.exe is a legitimate, pre-installed or trusted utility on Windows. It is classified as a Living-off-the-Land Binary (LOLBin) because adversaries abuse its built-in functionality to perform malicious operations—such as Defense Evasion, Credential Dump, Download—without dropping custom malware binaries on disk.
How do threat actors abuse Findstr.exe in cyber intrusions?
Adversaries leverage Findstr.exe to execute stealthy actions while evading signature-based security controls. For example, attackers execute commands like "findstr /V /L W3AllLov3LolBas {PATH_ABSOLUTE:.exe} > {PATH_ABSOLUTE}:file.exe" to achieve Defense Evasion, Credential Dump, Download, masquerading behind legitimate system process lineage.
How can SOC analysts detect suspicious Findstr.exe activity?
Detection engineers monitor process creation events (Windows Event ID 4688 or Sysmon Event ID 1; Linux auditd EXECVE; macOS Endpoint Security) inspecting anomalous command line arguments, unusual parent-child process relationships (e.g. Office apps or web servers spawning Findstr.exe), and unexpected network connections.
What MITRE ATT&CK techniques does Findstr.exe map to?
Findstr.exe maps to MITRE ATT&CK technique(s): T1564.004, T1552.001, T1105. These techniques cover adversary actions across tactics such as Defense Evasion, Execution, Persistence, and Command and Control.
How can organizations mitigate and restrict Findstr.exe?
Mitigation strategies include implementing Application Control policies (AppLocker or Windows Defender Application Control - WDAC), enforcing Attack Surface Reduction (ASR) rules, configuring strict privilege separation (disallowing standard users from running sensitive switches), and alerting on execution from non-standard directories.
Other High-Traffic WINDOWS LOLBins
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Background Intelligent Transfer Service (BITS) administrator tool manages asynchronous, throttled background transfers. Attackers use BITS to stage remote downloads that survive reboots and evade conventional network monitoring.