Cyber Apocalypse 2025: Day #2

The Cyber Apocalypse 2025 CTF features a "Tales from Eloria" theme with daily challenges from June 21–26, including a PowerShell malware analysis talk by David (Zero XDF) 1:30. The talk demonstrates analyzing a forensic packet capture to extract a hidden Discord Nitro flag by reverse-engineering a base64-encoded string, decrypting AES-CBC encrypted data using the key and IV, and identifying the token payload 25:03.

Key Takeaways:
• The CTF theme is "Tales from Eloria," running from June 21–26 1:30.
• The malware steals browser tokens using PowerShell, encrypts them with AES-CBC, and sends data to a remote endpoint 8:24.
• The flag is recovered by reversing a base64 string, decrypting AES-CBC data with the key and IV, and identifying the token payload 25:03.
• Advanced techniques like CyberChef register manipulation are used to extract the IV from encrypted data 34:00.

The event promotes learning and community over competition, encouraging participants to engage with challenges and collaborate.

Sources:

• 1:30 Overview of CTF theme, schedule, and prizes.
• 8:24 Introduction to the PowerShell malware analysis challenge and forensic data analysis.
• 25:03 Recovery of the flag via decryption and string reversal.
• 34:00 Demonstration of CyberChef register manipulation for IV extraction.