Windows Installer Execution via Explorer

Source: github.com/elastic/protections-artifacts

Identifies execution from an Msiexec installer in quiet mode and where the parent process is Explorer.exe. This may indicate execution via a malicious Windows shortcut file.

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1218.007` System Binary Proxy Execution: Msiexec

Rule body

[rule]
description = """
Identifies execution from an Msiexec installer in quiet mode and where the parent process is Explorer.exe. This may
indicate execution via a malicious Windows shortcut file.
"""
id = "65a7fb56-6f18-43d2-b799-a5b7359c8a3b"
license = "Elastic License v2"
name = "Windows Installer Execution via Explorer"
os_list = ["windows"]
reference = ["https://lolbas-project.github.io/lolbas/Binaries/Msiexec/"]
version = "1.0.2"

query = '''
process where event.action == "start" and
 process.name : "msiexec.exe" and process.args :("/i", "-i") and process.args : ("/qn", "-qn", "-q", "/q", "/quiet") and
 process.parent.executable : "?:\\Windows\\explorer.exe"
'''

min_endpoint_version = "7.15.0"
[[actions]]
action = "kill_process"
field = "process.entity_id"
state = 0

[[optional_actions]]
action = "rollback"
field = "process.entity_id"
state = 0

[[threat]]
framework = "MITRE ATT&CK"
[[threat.technique]]
id = "T1218"
name = "System Binary Proxy Execution"
reference = "https://attack.mitre.org/techniques/T1218/"
[[threat.technique.subtechnique]]
id = "T1218.007"
name = "Msiexec"
reference = "https://attack.mitre.org/techniques/T1218/007/"



[threat.tactic]
id = "TA0005"
name = "Defense Evasion"
reference = "https://attack.mitre.org/tactics/TA0005/"

[internal]
min_endpoint_version = "7.15.0"

Stages and Predicates

Stage 1: `process`

process where event.action == "start" and
 process.name : "msiexec.exe" and process.args :("/i", "-i") and process.args : ("/qn", "-qn", "-q", "/q", "/quiet") and
 process.parent.executable : "?:\\Windows\\explorer.exe"

Indicators

These rows show field, operator, and value matches.