Detection rules › Splunk
Suspicious Parent Process for msiexec.exe (Sysmon)
msiexec.exe is a Windows system component used to install and modify software packages using Windows Installer. Threat actors may abuse msiexec.exe to install malicious software or execute scripts, leveraging its legitimate appearance to bypass security measures and gain persistence on a targeted system as observed in FlawedGrace attacks. This use case detects executions of msiexec.exe with suspicious parent processes
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth | T1218.007 System Binary Proxy Execution: Msiexec |
References
Event coverage
| Provider | Event | Title |
|---|---|---|
| Sysmon | Event ID 1 | Process creation |
Rule body yaml
id: '24143.44553'
title: Suspicious Parent Process for msiexec.exe
description: msiexec.exe is a Windows system component used to install and modify
software packages using Windows Installer. Threat actors may abuse msiexec.exe to
install malicious software or execute scripts, leveraging its legitimate appearance
to bypass security measures and gain persistence on a targeted system as observed
in FlawedGrace attacks. This use case detects executions of msiexec.exe with suspicious
parent processes. Living Off the Land Binary and Scripts (LOLBAS) (LOLBIN)
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "<EventID>1<")
TERM(msiexec) OR "msiexec.exe" | regex parent_process_name="(?i)(spoolsv|powershell|pwsh|cmd|svchost|winlogon|taskhost|wininit)\.exe"
| table _time, host, user process, process_*, parent_process_name, parent_process_*
| bin span=1s | stats values(*) as * by _time, host '
techniques:
- defense-evasion:system binary proxy execution:msiexec
technique_id:
- T1218.007
data_category:
- Windows Sysmon
references:
- https://thedfirreport.com/2023/06/12/a-truly-graceful-wipe-out/
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "<EventID>1<") TERM(msiexec) OR "msiexec.exe"
Stage 2: regex
| regex parent_process_name="(?i)(spoolsv|powershell|pwsh|cmd|svchost|winlogon|taskhost|wininit)\.exe"
Stage 3: table
| table _time, host, user process, process_*, parent_process_name, parent_process_*
Stage 4: bucket
| bin span=1s
Stage 5: stats
| stats values(*) as * by _time, host
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 |
|---|---|---|
EventCode | eq |
|
parent_process_name | regex_match |
|
Search terms
Bare-string tokens in the SPL search body. Splunk matches each token against _raw (the untyped raw event text) anywhere it appears, not against a specific field. These don't surface in the Indicators table because they aren't predicates on a known field.
| Stage | Term |
|---|---|
| 1 | TERM |
| 1 | "<EventID>1<" |
| 1 | TERM |
| 1 | msiexec |
| 1 | "msiexec.exe" |