Reverse Engineering an Infostealer from PicusSecurity.news | Inside an Unknown Infostealer

[BLUF with citation]

This video details the reverse engineering of an info-stealer malware, analyzing its persistence mechanisms, data exfiltration methods, and communication with command-and-control (C2) servers 2:53.

Key Takeaways:
• The malware is an encrypted Windows executable that embeds a browser extractor DLL within its resources, which is decrypted and executed at runtime 3:28.
• It targets multiple browsers including Chrome, Edge, Brave, and Opera to steal credentials and session cookies 21:12.
• The infection process involves establishing persistence via registry keys and creating a mutex to prevent multiple instances 25:44.
• Data is exfiltrated using raw Windows Sockets (WS2_32) to communicate with a hardcoded C2 IP address 28:54.
• The malware employs encryption for its internal data and verifies the integrity of messages sent to the C2 server 34:13.
• The analyst identifies specific API calls for file persistence, such as writing to the registry, which helps in tracing the malware's behavior 25:44.

[Closing statement]

The analysis demonstrates how modern info-stealers use embedded payloads and standard Windows APIs to maintain persistence and securely transmit stolen data to attackers.

Sources:

• 2:53 Introduction to the malware file and initial analysis steps
• 3:28 Examination of encrypted resources using Resource Hacker
• 21:12 Identification of targeted browsers for credential theft
• 25:44 Analysis of persistence mechanisms and registry modifications
• 28:54 Reverse engineering of socket communication for C2 connectivity
• 34:13 Discussion on data encryption and integrity verification during exfiltration