Remote XSL Execution Via Msxsl.EXE

Status: test
Severity: high
Log source: category process_creation, product windows
Author: Swachchhanda Shrawan Poudel
Source: github.com/SigmaHQ/sigma

Detects the execution of the "msxsl" binary with an "http" keyword in the command line. This might indicate a potential remote execution of XSL files.

Known false positives

Msxsl is not installed by default and is deprecated, so unlikely on most systems.

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1220` XSL Script Processing

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: Remote XSL Execution Via Msxsl.EXE
id: 75d0a94e-6252-448d-a7be-d953dff527bb
status: test
description: Detects the execution of the "msxsl" binary with an "http" keyword in the command line. This might indicate a potential remote execution of XSL files.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1220/T1220.md
    - https://lolbas-project.github.io/lolbas/OtherMSBinaries/Msxsl/
author: Swachchhanda Shrawan Poudel
date: 2023-11-09
tags:
    - attack.stealth
    - attack.t1220
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: '\msxsl.exe'
        CommandLine|contains: 'http'
    condition: selection
falsepositives:
    - Msxsl is not installed by default and is deprecated, so unlikely on most systems.
level: high

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    Image|endswith: '\msxsl.exe'
    CommandLine|contains: 'http'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`http` corpus 52 (sigma 34, elastic 15, chronicle 2, splunk 1)	`field:"CommandLine" kind:match value:"http"`
`Image`	ends_with	`\msxsl.exe` corpus 6 (sigma 6)	`field:"Image" kind:ends_with value:"\msxsl.exe"`