Detect Path Interception by Search Order Hijacking in CrowdStrike LogScale
Adversaries may execute their own malicious payloads by hijacking the search order Windows uses to find programs called without a full path. When an executable calls a program by name only (e.g., 'net user' rather than 'C:\Windows\System32\net.exe user'), Windows first searches the current directory of the calling program, then the directories in PATH. An adversary who places a binary named 'net.exe' or 'net.com' (PATHEXT ordering: .COM before .EXE) in the same directory as the calling application will have their binary executed. Empire and PowerSploit both include modules to discover and exploit search order hijacking vulnerabilities across the system.
MITRE ATT&CK
- Technique
- T1574 Hijack Execution Flow
- Sub-technique
- T1574.008 Path Interception by Search Order Hijacking
- Canonical reference
- https://attack.mitre.org/techniques/T1574/008/
LogScale Detection Query
#event_simpleName in ("ProcessRollup2", "SyntheticProcessRollup2")
| ImageFileName = /(?i)\\temp\\.*\.exe/
| ParentBaseFileName != /(?i)(msiexec|trustedinstaller|wusa|dpinst|svchost)/
| UserName != "SYSTEM"
| UserName != ""
| groupBy([aid, ComputerName, ImageFileName, ParentBaseFileName, UserName, CommandLine], function=[count(as=EventCount), min(timestamp, as=FirstSeen)])
| case {
ImageFileName = /(?i)\\temp\\/i AND ParentBaseFileName = /(?i)(setup|install|update)/ => RiskScore := "High";
ImageFileName = /(?i)\\temp\\/i => RiskScore := "Medium";
* => RiskScore := "Low";
}
| where RiskScore in ("High", "Medium")
| table([ComputerName, UserName, ImageFileName, ParentBaseFileName, CommandLine, EventCount, RiskScore, FirstSeen])
| sort(RiskScore)CrowdStrike LogScale (Falcon) CQL detection for Path Interception by Search Order Hijacking. Detects system binary names (net.exe, cmd.exe, powershell.exe, etc.) executing from non-system directories. Windows search order hijacking relies on a copy of a commonly-invoked binary being placed in
Data Sources
Required Tables
False Positives & Tuning
- Legitimate enterprise installers that update extracted binaries during installation
- Software deployment tools (SCCM, Intune) staging and modifying installers in temp
- Self-patching applications that download and replace their own components
- Automated software update mechanisms that modify binaries before execution
Other platforms for T1574.008
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 1Create Fake Net.exe in Application Directory
Expected signal: Sysmon Event ID 11 (FileCreate): net.exe created in TEMP subdirectory. If subsequently executed: Sysmon Event ID 1 showing net.exe running from %TEMP%\vulnerable-app rather than System32.
- Test 2Search Order Hijacking via .COM Extension (PATHEXT)
Expected signal: Process creation events showing test.com executed instead of test.exe when called by name only. The CurrentDirectory in the process creation event shows the TEMP directory.
- Test 3PowerSploit Find-PathDLLHijack Discovery
Expected signal: Sysmon Event ID 1: powershell.exe with PATH enumeration command. Sysmon Event ID 11: temporary test files created and deleted in writable PATH directories. PowerShell ScriptBlock Log Event ID 4104 with the enumeration script.
References (4)
- https://attack.mitre.org/techniques/T1574/008/
- https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-createprocessa
- https://github.com/PowerShellMafia/PowerSploit/blob/master/Privesc/PowerUp.ps1
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1574.008/T1574.008.md
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