Detection rules › Splunk
Certutil Execution (Windows Event Log)
certutil is a command-line utility that can be used to obtain certificate authority information and configure Certificate Services. This use case looks for process executions of certutil
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Stealth | T1027 Obfuscated Files or Information, T1140 Deobfuscate/Decode Files or Information |
| Command & Control | T1105 Ingress Tool Transfer, T1132 Data Encoding |
References
Event coverage
| Provider | Event | Title |
|---|---|---|
| Security-Auditing | Event ID 4688 | A new process has been created. |
Rule body yaml
id: '6167.6701'
title: Certutil Execution
description: 'certutil is a command-line utility that can be used to obtain certificate
authority information and configure Certificate Services. This use case looks for
process executions of certutil. -- Threat Actor Association: DarkSide, BlackMatter,
REvil - Software Association: HermeticWiper/Trojan.Killdisk -- Living Off the Land
Binary and Scripts (LOLBAS) (LOLBIN) -- Atomics 1003.002 Test #5 Atomics 1140 Test
#1'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR
"<EventID>4688<" OR Type=Process) (TERM(certutil) OR "certutil.exe") | table _time,
host, user, signature_id, process, process_*, parent_* | bin span=1s | stats values(*)
as * by _time, host | where match(process_name, "(?i)certutil") '
techniques:
- command-and-control:data encoding
- command-and-control:ingress tool transfer
- defense-evasion:deobfuscate/decode files or information
- defense-evasion:obfuscated files or information
technique_id:
- T1132
- T1105
- T1140
- T1027
data_category:
- Windows event logs
references:
- https://lolbas-project.github.io/lolbas/Binaries/Certutil/
- https://www.fireeye.com/blog/threat-research/2018/09/apt10-targeting-japanese-corporations-using-updated-ttps.html
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_winevent` (TERM(EventCode=4688) OR "<EventID>4688<" OR Type=Process) (TERM(certutil) OR "certutil.exe")
Stage 2: table
| table _time, host, user, signature_id, process, process_*, parent_*
Stage 3: bucket
| bin span=1s
Stage 4: stats
| stats values(*) as * by _time, host
Stage 5: where
| where match(process_name, "(?i)certutil")
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 |
|
process_name | 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>4688<" |
| 1 | TERM |
| 1 | certutil |
| 1 | "certutil.exe" |