Dissecting Mac.Banshee: An In-Depth Analysis of a Mac Malware

• 0:00:03 Introduction: The video analyzes the Mac.Banshee stealer, a malware written in Objective-C, whose source code was leaked.
• 0:00:51 Objective-C Basics: A brief crash course on Objective-C is provided, covering class definitions, methods, and syntax, to aid understanding for those unfamiliar with the language.
• 0:05:13 Initial Overview: The speaker begins by examining the header files to understand the malware's potential functionality. Key classes like AntiVM, Browsers, Controller, System, Tools, and CollectWallet are identified.
• 0:09:09 Main Execution Flow: The malware's main function is analyzed. It relaunches itself with an encryption key and executes the manage function within the Controller class.
• 0:11:10 Controller Class Analysis:
  • 0:11:18 Initialization: The Controller is initialized with an encryption key and sets up other classes (Tools, AntiVM, System, Browsers, Sender, Wallets).
  • 0:12:47 manage Function: This function contains the core logic.
    • Anti-VM Checks (0:12:47): It checks for debuggers using ptrace and virtual machines by examining system profiler output.
    • Temporary Directory Creation (0:16:55): A temporary directory is created for storing stolen data.
    • macOS Password Retrieval (0:18:50): The malware attempts to steal the user's password using an osascript prompt and verifies it using dscl.
    • Browser Data Collection (0:23:13): Data from various browsers (Chrome, Firefox, Brave, Edge, Vivaldi, Yandex, Opera) is collected, including history, cookies, login data, and crypto wallet extensions.
    • System Information Gathering (0:31:32): System and hardware information, along with the public IP, is collected and stored.
    • File Grabbing (0:41:22): The malware copies Safari data, notes, and specific file types from the Desktop and Documents folders using an embedded AppleScript.
    • Keychain Dumping (0:50:24): Keychain passwords are stolen.
    • Wallet Data Theft (0:52:06): Data from various cryptocurrency wallets is copied.
    • Data Compression and Encryption (0:57:10): Collected data is compressed into a ZIP archive and encrypted using a 15-character XOR key.
    • C2 Communication (0:58:13): The encrypted data is base64-encoded and sent to a command-and-control (C2) server via an HTTP POST request.
    • Cleanup (1:04:02): The malware attempts to delete the temporary folder and files.
• 1:11:12 Critique:
  • Strengths: The malware is functional and effective in stealing data.
  • Weaknesses:
    • Lacks proper evasion techniques (easily detectable strings, predictable behavior).
    • Poor anti-VM checks.
    • Insecure data storage in a temporary folder.
    • Writes an un-obfuscated AppleScript file to disk during execution.
• 1:13:57 Conclusion: The analysis provides a detailed understanding of the Mac.Banshee stealer's functionality, highlighting its strengths and weaknesses. The speaker emphasizes the importance of secure coding practices and the relative ease with which this particular malware can be detected and analyzed.
• 1:14:14 Recommendations: The speaker suggests resources like Objective-See for further learning about macOS security.