Forensic - Tricky Malware (481 pts)

Description

My SOC detected there are Ransomware that decrypt file for fun. The script kiddies is so tricky. Here some evidence that we successfully retrieve.

Author: 4jai

File : ;

Hint : The malware seems trying to establish connection to mothership. I wonder where is it.

Solution

We were given a rar file. Inside, we find 2 file, memdump.mem and network.pcap

From the hint, we need to check the connection to some suspicious C2 server. We can open the pcap file with wireshark

To my surprise, we find some attempt to connect to pastebin. We can try to just strings the memory dump to search for any strings that starts with pastebin

We find some kind of powershell command, possibly with malicious intent, to downloads and executes additional suspicious components hosted on remote URLs. We can see that there are some kind of obfuscation with concatenation and dynamic content fetching, some kind of persistence mechanism, and “hidden” command in the powershell script

But, one of the pastebin is refer to the flag, which is

Flag

WGMY{8b9777c8d7da5b10b65165489302af32}