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Course 6 - Network Traffic Analysis for Incident Response | Episode 6: Investigating RATs, Worms, Fileless, and Multi-Stage Malware Variants
Published 6 months, 1 week ago
Description
In this lesson, you’ll learn about: Advanced Malware Traffic Analysis — how to detect, decode, and investigate RATs, fileless exploits, worms, and multi-stage infections using real network captures. 1. Remote Access Trojans (RATs) WSH RAT
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- Uses plaintext beaconing for C2 → very easy to identify.
- Key data exfiltrated in HTTP requests:
- Unique device ID
- Computer name
- Username (“admin”)
- RAT version (often hidden in the User-Agent field)
- Shows extensive data exfiltration:
- Windows XP build info
- CPU type (Intel Core i7)
- Username (“Laura”)
- Contains custom data blocks:
- Likely a proprietary C2 format
- Example: 4-byte value representing payload length (e.g., 16 bytes)
- Traffic contains obfuscated script + random literature quotes
→ used to evade heuristic scanners. - Streams show signs of XOR encoding.
- Extracted files include:
- A Shockwave Flash file (.swf)
- Three large application/octet-stream files
- XOR decoding reveals:
- Shellcode +
- Windows executable (DLL)
- Shellcode injects the malicious DLL into a running process (e.g., Internet Explorer).
- Because nothing is written to disk → bypasses traditional antivirus, making network analysis essential.
- Exploits SMB on port 445 using Eternal-family vulnerabilities.
- Behavior includes:
- High-volume IP scanning for vulnerable systems
- SMB exploitation setup (NOP sled → shellcode → payload transfer)
- Attempts spreading via SMTP (port 25).
- Tries to send spoofed “delivery failed” emails with malicious attachments:
- e.g., mail.zip → actually .exe hidden using spaces + triple dots.
- In the demonstration, all spreading attempts were blocked, showing modern protections in action.
- Suspicious HTTP request containing Base64 ID.
- Decodes to an email address (e.g., Reginald/Reggie Cage) → privacy red flag.
- Download of a malicious Microsoft Word file.
- Traffic to known malware-downloader domains (e.g., Pony botnet infrastructure).
- Malware sends detailed victim metadata:
- GUID
- OS build number
- IP address
- Hardware info
- Multiple C2 messages observed:
- Some Base64-encoded
- Many encrypted → indicating later-stage payloads
- Strong evidence that:
- Word file → downloader (Pony) → secondary malware → possible tertiary stage
- Identifying IOCs in network captures
- Detecting plaintext, encoded, and encrypted C2 protocols
- Carving files and reconstructing injected payloads
- Analyzing worm scanning patterns
- Tracking infection chains across multiple malicious components
You can listen and download our episodes for free on more than 10 different platforms:
https://linktr.ee/cybercode_academy