Ostap Loader (also known as Ostap) is a malware loader active since 2019. JavaScript-based loader. Key characteristics include: JScript downloader, Office macro delivery, TrickBot/IcedID distribution.
Overview & Background
JavaScript-based loader. First identified in 2019, this threat is attributed to eCrime.
Threat Assessment
Ostap Loader remains an active threat. Organizations should implement detection rules and monitor for indicators associated with this malware loader.
- Category: Malware Loader
- Active since: 2019
- Attribution: eCrime
- Also known as: Ostap
Technical Analysis
Ostap Loader employs the following capabilities and techniques:
- Jscript Downloader: Core functionality
- Office Macro Delivery: Core functionality
- Trickbot/Icedid Distribution: Core functionality
MITRE ATT&CK Mapping
| Tactic | Technique | Usage |
|---|---|---|
| Initial Access | T1566.001 Phishing Attachment | Common delivery vector |
| Execution | T1204.002 Malicious File | User-triggered execution |
| Persistence | T1547.001 Registry Run Keys | Autostart persistence |
| Defense Evasion | T1027 Obfuscated Files | Payload obfuscation |
| C2 | T1071.001 Web Protocols | HTTP/HTTPS C2 |
Detection & Defense
- Endpoint detection: Deploy behavioral detection rules for Ostap Loader indicators
- Network monitoring: Monitor for C2 traffic patterns and anomalous connections
- Threat intelligence: Track Ostap Loader IOCs and campaign updates
- Security awareness: Train users to recognize phishing and social engineering
- Patch management: Keep systems updated to prevent exploitation
Defend Against Ostap Loader
Mjolnir Security provides detection and response capabilities against Ostap Loader and similar threats.
Threat DetectionIncident ResponseThreat HuntingMDR ServicesThreat Intelligence
- Proactive Threat Hunting Hunt for Ostap Loader indicators and TTPs within your environment.
- Threat Intelligence Monitor Ostap Loader campaigns and infrastructure changes.
- 24/7 Incident Response Rapid containment and forensic investigation. Call +1 833 403 5875.
Written by: Mjolnir Security | Published: September 20, 2025
Stay ahead of emerging threats. Get notified when we publish new intelligence reports and advisories.
Subscribe to Alerts