WSL Kali-Linux Usage

Severity: high
Author: Swachchhanda Shrawan Poudel (Nextron Systems)
Source: upstream

Detects the use of Kali Linux through Windows Subsystem for Linux

MITRE ATT&CK coverage

Tactic	Techniques
Defense Evasion	`T1202` Indirect Command Execution

Event coverage

Provider	Event ID	Title
Sysmon	1	Process creation
Security-Auditing	4688	A new process has been created.

Stages and Predicates

Stage 1: `1 of selection_img_appdata`

or:
Image|contains: ':\Users\'
Image|contains: '\AppData\Local\Microsoft\WindowsApps\kali.exe'
Image|contains: ':\Users\'
Image|contains: '\AppData\Local\packages\KaliLinux'

Stage 2: `1 of selection_img_windowsapps`

Image|endswith: '\kali.exe'
Image|contains: ':\Program Files\WindowsApps\KaliLinux.'

Stage 3: `all of selection_kali_wsl_parent`

or:
ParentImage|endswith: '\wsl.exe'
ParentImage|endswith: '\wslhost.exe'

Stage 4: `all of selection_kali_wsl_child`

or:
CommandLine|contains: Kali-linux
CommandLine|contains: Kali.exe
CommandLine|contains: kalilinux
Image|contains: '\KaliLinux'
Image|contains: '\kali.exe'

Stage 5: `not 1 of filter_main_install_uninstall`

or:
CommandLine|contains: ' --install '
CommandLine|contains: ' --unregister '
CommandLine|contains: ' -i '

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

Field	Kind	Values
`CommandLine`	match	`--install` corpus 2 (sigma 2) `--unregister` `-i` corpus 3 (sigma 3) `Kali-linux` `Kali.exe` `kalilinux`
`Image`	ends_with	`\kali.exe`
`Image`	match	`:\Program Files\WindowsApps\KaliLinux.` `:\Users\` corpus 3 (sigma 3) `\AppData\Local\Microsoft\WindowsApps\kali.exe` `\AppData\Local\packages\KaliLinux` `\KaliLinux` `\kali.exe`
`ParentImage`	ends_with	`\wsl.exe` corpus 4 (sigma 4) `\wslhost.exe` corpus 2 (sigma 2)

WSL Kali-Linux Usage

MITRE ATT&CK coverage

Event coverage

Stages and Predicates

Stage 1: 1 of selection_img_appdata

Stage 2: 1 of selection_img_windowsapps

Stage 3: all of selection_kali_wsl_parent