Detection rules › Splunk
Cmstp Execution (Windows Event Log)
Adversaries may abuse CMSTP to proxy execution of malicious code. The Microsoft Connection Manager Profile Installer (CMSTP.exe) is a command-line program used to install Connection Manager service profiles. CMSTP.exe accepts an installation information file (INF) as a parameter and installs a service profile leveraged for remote access connections
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth | T1218.003 System Binary Proxy Execution: CMSTP |
References
Event coverage
| Provider | Event | Title |
|---|---|---|
| Security-Auditing | Event ID 4688 | A new process has been created. |
Rule body yaml
id: '13810.20277'
title: Cmstp Execution
description: 'Adversaries may abuse CMSTP to proxy execution of malicious code. The
Microsoft Connection Manager Profile Installer (CMSTP.exe) is a command-line program
used to install Connection Manager service profiles. CMSTP.exe accepts an installation
information file (INF) as a parameter and installs a service profile leveraged for
remote access connections. Living Off the Land Binary and Scripts (LOLBAS) (LOLBIN)
Atomics T1218.003 Test #1 Atomics T1218.003 Test #2'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR
"<EventID>4688<" OR Type=Process) ("cmstp.exe") OR ("/s" "/.inf") OR "/ni" OR "/ns"
| regex process="(?i)cmstp|\s+\/s\s+.+\.inf|\s+\/ni\s+.{4,}|\s+\/ns\s+.{4,}" | table
_time, host, user process, process_*, signature_id, parent_* | bin span=1s | stats
values(*) as * by _time, host '
techniques:
- defense-evasion:system binary proxy execution:cmstp
technique_id:
- T1218.003
data_category:
- Process command-line parameters
- Windows event logs
references:
- https://lolbas-project.github.io/lolbas/Binaries/Cmstp/
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR "<EventID>4688<" OR Type=Process) ("cmstp.exe") OR ("/s" "/.inf") OR "/ni" OR "/ns"
Stage 2: regex
| regex process="(?i)cmstp|\s+\/s\s+.+\.inf|\s+\/ni\s+.{4,}|\s+\/ns\s+.{4,}"
Stage 3: table
| table _time, host, user process, process_*, signature_id, parent_*
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.
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>4688<" |
| 1 | "cmstp.exe" |
| 1 | "/s" |
| 1 | "/.inf" |
| 1 | "/ni" |
| 1 | "/ns" |