Detection rules › Splunk
Rare executable from Microsoft Office (Sysmon)
This use case looks for suspicious behavior from Microsoft office products. Filters for rarer executable files launched from a Microsoft Office product
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Execution |
References
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Sysmon | Event ID 1: Process creation |
Rule body
id: '11211.15637'
title: Rare executable from Microsoft Office
description: 'This use case looks for suspicious behavior from Microsoft office products.
Filters for rarer executable files launched from a Microsoft Office product. - Threat
Actor Association: Evilnum - Software Association: GlowSand.'
logic_format: Splunk
logic: '`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "<EventID>1<")
((TERM(Microsoft) TERM(Office)) OR TERM(WINWORD.EXE) OR TERM(EXCEL.EXE) OR TERM(POWERPNT.EXE)
OR TERM(MSACCESS.EXE) OR TERM(OUTLOOK.EXE) OR TERM(VISIO.EXE) OR TERM(WINPROJ.EXE)
OR TERM(wordpad.exe))| regex parent_process_name="(?i)((WINWORD\.EXE)|(EXCEL\.EXE)|(POWERPNT\.EXE)|(MSACCESS\.EXE)|(OUTLOOK\.EXE)|(VISIO\.EXE)|(WINPROJ\.EXE)|(wordpad\.exe)|(Microsoft\s+Office))"
| table _time, host, user process, parent_*, process_*, signature_id | bin span=1s
| stats values(*) as * by _time, host | eventstats c(process_name) as c_process
by process_name| where c_process < 3 '
techniques:
- execution:user execution:malicious file
technique_id:
- T1204.002
data_category:
- Windows Sysmon
references:
- https://borncity.com/win/2022/06/02/searchnightmare-windows-10-search-ms-uri-handler-0-day-exploit-mit-office-2019/
Stages and Predicates
Stage 1: search
`get_endpoint_data` `get_endpoint_data_sysmon` (TERM(EventCode=1) OR "<EventID>1<") ((TERM(Microsoft) TERM(Office)) OR TERM(WINWORD.EXE) OR TERM(EXCEL.EXE) OR TERM(POWERPNT.EXE) OR TERM(MSACCESS.EXE) OR TERM(OUTLOOK.EXE) OR TERM(VISIO.EXE) OR TERM(WINPROJ.EXE) OR TERM(wordpad.exe))
Stage 2: regex
| regex parent_process_name="(?i)((WINWORD\.EXE)|(EXCEL\.EXE)|(POWERPNT\.EXE)|(MSACCESS\.EXE)|(OUTLOOK\.EXE)|(VISIO\.EXE)|(WINPROJ\.EXE)|(wordpad\.exe)|(Microsoft\s+Office))"
Stage 3: table
| table _time, host, user process, parent_*, process_*, signature_id
Stage 4: bucket
| bin span=1s
Stage 5: stats
| stats values(*) as * by _time, host
Stage 6: eventstats
| eventstats c(process_name) as c_process by process_name
Stage 7: where
| where c_process < 3
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
EventCode | eq |
| field:"EventID" kind:eq value:"1" |
c_process | lt |
| field:"c_process" kind:lt value:"3" |
parent_process_name | regex_match |
| field:"parent_process_name" kind:regex_match |
Search terms
These SPL tokens match against raw event text.
| Stage | Term |
|---|---|
| 1 | "<EventID>1<" |
| 1 | Microsoft |
| 1 | Office |
| 1 | WINWORD.EXE |
| 1 | EXCEL.EXE |
| 1 | POWERPNT.EXE |
| 1 | MSACCESS.EXE |
| 1 | OUTLOOK.EXE |
| 1 | VISIO.EXE |
| 1 | WINPROJ.EXE |
| 1 | wordpad.exe |