Potentially Suspicious WebDAV LNK Execution

Status: test
Severity: medium
Log source: category process_creation, product windows
Author: Micah Babinski
Source: github.com/SigmaHQ/sigma

Detects possible execution via LNK file accessed on a WebDAV server.

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059.001` Command and Scripting Interpreter: PowerShell `T1204` User Execution

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation
Security-Auditing	Event ID 4688: A new process has been created.

Rule body

title: Potentially Suspicious WebDAV LNK Execution
id: 1412aa78-a24c-4abd-83df-767dfb2c5bbe
related:
    - id: f0507c0f-a3a2-40f5-acc6-7f543c334993
      type: similar
status: test
description: Detects possible execution via LNK file accessed on a WebDAV server.
references:
    - https://www.trellix.com/en-us/about/newsroom/stories/research/beyond-file-search-a-novel-method.html
    - https://micahbabinski.medium.com/search-ms-webdav-and-chill-99c5b23ac462
author: Micah Babinski
date: 2023-08-21
tags:
    - attack.execution
    - attack.t1059.001
    - attack.t1204
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        ParentImage|endswith: '\explorer.exe'
        Image|endswith:
            - '\cmd.exe'
            - '\cscript.exe'
            - '\mshta.exe'
            - '\powershell.exe'
            - '\pwsh.exe'
            - '\wscript.exe'
        CommandLine|contains: '\DavWWWRoot\'
    condition: selection
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    ParentImage|endswith: '\explorer.exe'
    Image|endswith:
        - '\cmd.exe'
        - '\cscript.exe'
        - '\mshta.exe'
        - '\powershell.exe'
        - '\pwsh.exe'
        - '\wscript.exe'
    CommandLine|contains: '\DavWWWRoot\'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`\DavWWWRoot\` corpus 3 (sigma 2, elastic 1)	`field:"CommandLine" kind:match value:"\DavWWWRoot\"`
`Image`	ends_with	`\cmd.exe` corpus 130 (sigma 130) `\cscript.exe` corpus 72 (sigma 72) `\mshta.exe` corpus 66 (sigma 66) `\powershell.exe` corpus 179 (sigma 178, kusto 1) `\pwsh.exe` corpus 165 (sigma 164, kusto 1) `\wscript.exe` corpus 74 (sigma 74)	`field:"Image" kind:ends_with`
`ParentImage`	ends_with	`\explorer.exe` corpus 13 (sigma 13)	`field:"ParentImage" kind:ends_with value:"\explorer.exe"`

Potentially Suspicious WebDAV LNK Execution

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection

Indicators

Stage 0: `condition`

Stage 1: `selection`