Suspicious Office Application Spawning Regsvr32 via Process Chain (via process_creation)

ATT&CK techniques

Initial Access → Defense Evasion

Recon
Resource Dev
Initial Access
- T1566.001Spearphishing Attachment
Execution
Persistence
Priv Esc
Defense Evasion
- T1218.010Regsvr32
Cred Access
Discovery
Lateral Movement
Collection
C2
Exfiltration
Impact

What it detects

This rule detects Microsoft Office applications spawning regsvr32.exe as a child process, a common code execution pattern from malicious documents. It is associated with campaigns abusing regsvr32 through weaponized Office files reported by Uptycs. Office products rarely need to launch regsvr32 directly, so this parent-child relationship is a strong indicator of macro or embedded-object driven execution.

Reporting behind it

Related detections9 linkedT1218.010 — drag to rearrange

Suspicious Regsvr32 Squiblydoo Remote Scriptlet Execution via Command Line (via process_creation)

Windows Process Creation: Suspicious Children Spawned by HTML Help (hh.exe)

Windows: Alert on Suspicious HH.EXE Process Execution

Suspicious Script Host Spawning Regsvr32 via Strela Stealer JScript Loader (via process_creation)

Suspicious OneNote Spawning Command or Script Interpreter via Spear-Phishing (via process_creation)

Malicious DLL Registration via regsvr32 Loading prnfldr (via process_creation)

Suspicious Regsvr32 Execution of SafePay Loader DLL

Suspicious RDP Connection File Opened From Download or Mail Directory via Process Creation

Suspicious Code of Conduct Phishing Email From cocinternal.com Sender (via m365)

Suspicious Office Application Spawning Regsvr32 via Process Chain (via process_creation)

Pivot detection · T1218.010 · 9 related

Detection content is published as a reviewed draft. Tune thresholds and exclusions against your own telemetry before enabling this rule for alerting.

Full detection rule

Unlock this rule to view and copy it

The detection logic is included with a plan. Everything else — context, mappings and implementation details — stays free on this page.

Sign in for 3 free unlocks

Signing in gives you 3 unlocks to spend on any rule in the library. No card, and they do not expire.

Also included

Unlocked rules convert on this page — to Splunk SPL or Splunk — Raw Index SPL or Microsoft Sentinel KQL or Microsoft Sentinel ASIM ASIM KQL or Microsoft Defender XDR KQL or Elastic Security KQL or Elastic Security Lucene or Elastic Security ES|QL or CrowdStrike Falcon CQL or SentinelOne PowerQuery or Palo Alto Cortex XDR XQL or Carbon Black Cloud Platform Search or Carbon Black EDR Process Search or Google Security Operations UDM Search or IBM QRadar AQL or Sumo Logic Cloud SIEM Rules expression or Rapid7 InsightIDR LEQL or Graylog Search or OpenSearch Lucene or OpenSearch PPL PPL or Grafana Loki LogQL or SQLite SQL or Zircolite SQLite — with the log-source profile the engine picked, the field map it used, and everything it could not express. Converting a rule you have unlocked costs no further credit.

See it run on a free rule →Convert your own rule →