Suspicious Kimsuky JS Downloader Staging in Public and Templates Paths (via file_event)

ATT&CK techniques

C2

Recon
Resource Dev
Initial Access
Execution
Persistence
Priv Esc
Defense Evasion
Cred Access
Discovery
Lateral Movement
Collection
C2
- T1105Ingress Tool Transfer
Exfiltration
Impact

What it detects

This rule detects the creation of Kimsuky downloader and launcher scripts such as DefenderUpdate.js in Public Downloads or Templates.js and Templates.ps1 in the Windows Templates directory. These filenames and locations are used by the PebbleDash infection chain to stage follow on payloads.

Reporting behind it

Related detections9 linkedT1105 — drag to rearrange

Suspicious Remote HTA Payload Execution via MSHTA

Possible PurpleFox MSHTA to Msiexec Remote MSI Chain

Antivirus Check and Remote Loader Retrieval in LNK Command Chain

Suspicious PowerShell Hidden Web Download via Invoke-WebRequest by CatB Ransomware

Malicious Remote MSI Execution with Image Extension via msiexec (via process_creation)

Malicious ActiveMQ Exploitation Java Spawning PowerShell Downloader (via process_creation)

Malicious Sobolan Payload Download from Jupyter Compromise (via process_creation)

Suspicious Payload Download from Filebin via wget (via process_creation)

Suspicious Certutil UrlCache Download of Remote CAB Payload (via process_creation)

Suspicious Kimsuky JS Downloader Staging in Public and Templates Paths (via file_event)

Pivot detection · T1105 · 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 →