The screenshot is from AdGuardHome
Then I used an LLM to walk me through digging deeper for the first time, and then analyzing the output. Here are the highlights.
Code:
#snooping on the boox device and trying to visit a website
tcpdump -i br-lan host 192.168.1.221 -w capture.pcap >> output.txt
scp router:output.txt .
Then I uploaded output.txt to Claude AI:
(After uploading the same file to ChatGPT w/o context, I think that the response below is a false positive on what is actually being shared, but that its prior identification of potential domain generation algorithms still seems probable)
Quote:
Looking at this DNS traffic and subsequent data transfers, there are several concerning patterns: - The DGA-like (Domain Generation Algorithm) domains seen earlier appear to be communicating with your local DNS server (192.168.1.223) on port 8232
- The large data transfers following these DNS queries are significant:
- Multiple TCP connections being established
- Large amounts of data being transferred (2MB+ in one session)
- Consistent patterns of data transfer sizes (1448 byte chunks)
- Multiple sequential connections in a short timeframe
- The traffic pattern suggests command & control (C2) behavior:
- Initial DNS queries to establish connectivity
- Follow-up large data transfers
- Multiple connections in sequence
- Predictable timing patterns
- The device seems to be regularly beaconing out:
- DNS queries every few seconds
- Followed by data transfers
- Very systematic and automated looking behavior
- Block outbound traffic from this device at the router level
- Create firewall rules to block the suspicious port 8232 traffic
- Consider isolating the device to a separate VLAN
- Monitor for similar patterns from other devices
Would you like me to help create specific firewall rules to block this traffic or suggest how to isolate the device on your network?
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