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T1574.007 Path Interception by PATH Environment Variable

Adversaries may execute their own malicious payloads by hijacking environment variables used to load libraries. Adversaries may place a program in an earlier entry in the list of directories stored in the PATH environment variable, which Windows will then execute when it searches sequentially through that PATH listing in search of the binary that was called from a script or the command line.

The PATH environment variable contains a list of directories. Certain methods of executing a program (namely using cmd.exe or the command-line) rely solely on the PATH environment variable to determine the locations that are searched for a program when the path for the program is not given. If any directories are listed in the PATH environment variable before the Windows directory, %SystemRoot%\system32 (e.g., C:\Windows\system32), a program may be placed in the preceding directory that is named the same as a Windows program (such as cmd, PowerShell, or Python), which will be executed when that command is executed from a script or command-line.

For example, if C:\example path precedes C:\Windows\system32 is in the PATH environment variable, a program that is named net.exe and placed in C:\example path will be called instead of the Windows system “net” when “net” is executed from the command-line.

Item Value
ID T1574.007
Sub-techniques T1574.001, T1574.002, T1574.004, T1574.005, T1574.006, T1574.007, T1574.008, T1574.009, T1574.010, T1574.011, T1574.012, T1574.013
Tactics TA0003, TA0004, TA0005
CAPEC ID CAPEC-13, CAPEC-38
Platforms Windows
Version 1.0
Created 13 March 2020
Last Modified 16 September 2020

Procedure Examples

ID Name Description
S0363 Empire Empire contains modules that can discover and exploit path interception opportunities in the PATH environment variable.10
S0194 PowerSploit PowerSploit contains a collection of Privesc-PowerUp modules that can discover and exploit path interception opportunities in the PATH environment variable.1112

Mitigations

ID Mitigation Description
M1047 Audit Find and eliminate path interception weaknesses in program configuration files, scripts, the PATH environment variable, services, and in shortcuts by surrounding PATH variables with quotation marks when functions allow for them. Be aware of the search order Windows uses for executing or loading binaries and use fully qualified paths wherever appropriate.
M1038 Execution Prevention Adversaries will likely need to place new binaries in locations to be executed through this weakness. Identify and block potentially malicious software executed path interception by using application control tools, like Windows Defender Application Control, AppLocker, or Software Restriction Policies where appropriate.123456
M1022 Restrict File and Directory Permissions Ensure that proper permissions and directory access control are set to deny users the ability to write files to the top-level directory C: and system directories, such as C:\Windows\, to reduce places where malicious files could be placed for execution. Require that all executables be placed in write-protected directories.

Detection

ID Data Source Data Component
DS0022 File File Creation
DS0009 Process Process Creation
DS0024 Windows Registry Windows Registry Key Modification

References

  1. Beechey, J.. (2014, November 18). Application Whitelisting: Panacea or Propaganda?. Retrieved November 18, 2014. ↩

  2. Gorzelany, A., Hall, J., Poggemeyer, L.. (2019, January 7). Windows Defender Application Control. Retrieved July 16, 2019. ↩

  3. Tomonaga, S. (2016, January 26). Windows Commands Abused by Attackers. Retrieved February 2, 2016. ↩

  4. NSA Information Assurance Directorate. (2014, August). Application Whitelisting Using Microsoft AppLocker. Retrieved March 31, 2016. ↩

  5. Corio, C., & Sayana, D. P.. (2008, June). Application Lockdown with Software Restriction Policies. Retrieved November 18, 2014. ↩

  6. Microsoft. (2012, June 27). Using Software Restriction Policies and AppLocker Policies. Retrieved April 7, 2016. ↩

  7. Microsoft. (n.d.). CreateProcess function. Retrieved December 5, 2014. ↩

  8. Kanthak, S.. (2016, July 20). Vulnerability and Exploit Detector. Retrieved February 3, 2017. ↩

  9. Schroeder, W., Warner, J., Nelson, M. (n.d.). Github PowerShellEmpire. Retrieved April 28, 2016. ↩

  10. PowerShellMafia. (2012, May 26). PowerSploit - A PowerShell Post-Exploitation Framework. Retrieved February 6, 2018. ↩

  11. PowerSploit. (n.d.). PowerSploit. Retrieved February 6, 2018. ↩

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