UPLINK SOC / WRITE-UPS / LETSDEFEND / LETSDEFEND - PCAP ANALYSIS TLP:CLEAR LETSDEFEND SOLVED GITHUB CASE · 2026-07-23

LetsDefend - PCAP Analysis

Created: 22/02/2024 14:28 Last Updated: 22/02/2024 15:16


PCAP Analysis 6b0df1791fdcf814308866740fa93af3.png

We have captured this traffic from P13's computer. Can you help him?

File Location: /root/Desktop/ChallengeFile/Pcap_Analysis.pcapng


Start Investigation

I started by looking at the statistics of this pcapng file

a6856e21ec5291c711c20b658e2ea985.png There are a lot of IP addresses that were captured. 6feb7df4c4f9b883ca78e7c6b6efc3d8.png Protocol that was used the most is UDP Data and there are also a bunch of TCP protocol including HTTP that got captured as well

I don't think I can get the valuable information from TLS and UDP so I shifted my focus on TCP and Follow TCP stream

80f1f38ee22f51e7343652ecccf7cb96.png Look like I found a chat? look like P13 and Cu713 has a communicatation.

Cu713 had created a new file encryption scrip and challenge P13 to find it so the script might be found on this pcapng as well and might upload to the server so HTTP it is

ba3af9733ccaf3d7cd7a07ce543a2a3d.png 5964e7766f1805ec6e1493802ed9ea3b.png a504f594617883e883d93c46ee297a8f.png I filtered with 192.168.235.137 as a source and found out that this IP address uploaded file to an Apache web server (192.168.1.7) which was saved at uploads directory

Look like We got most of the question done


In network communication, what are the IP addresses of the sender and receiver?
Answer Format: SenderIPAddress,ReceiverIPAddress

192.168.235.137,192.168.235.131

P13 uploaded a file to the web server. What is the IP address of the server?

192.168.1.7

What is the name of the file that was sent through the network?

file

What is the name of the web server where the file was uploaded?

apache

What directory was the file uploaded to?

uploads

How long did it take the sender to send the encrypted file?

This question can be answered by looking at Conversations of the sender IP and server IP address at Statistics

91ed640fc265097b72367123cb99f50d.png

0.0073

Summary

A communication between 2 user P13 and Cu713 was captured, There was a challenge to found a new encryption script that was hiding somewhere and that somewhere is the Apache web server on the same local network and that file was named file and upload via /panel.php to the uploads directory

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