How to Automate Malware Analysis and Unpack Obfuscated Samples with x64dbg
/ 3 min read
Quick take - A recent video demonstration highlights the capabilities of x64dbg in reverse engineering by unpacking a complex 4-stage malware sample, showcasing various techniques and scripting functionalities that enhance malware analysis and debugging processes.
Fast Facts
- The video demonstrates x64dbg’s capabilities in unpacking a complex 4-stage malware sample obfuscated with SmartAssembly, highlighting the detailed analysis required.
- The unpacking process involves multiple stages, including a simple XOR decryption, and utilizes .NET executables “Zen” and “AProject” for payload extraction.
- The malware employs process hollowing via RunPE to inject the payload into a child process, with key API calls aiding in memory management and analysis.
- x64dbg’s scripting features automate tasks like setting breakpoints and saving payloads, enhancing the efficiency and accuracy of malware analysis.
- Additional resources, including a Udemy course for beginners and links to documentation, are provided to support viewers in their malware analysis journey.
Unpacking Malware with x64dbg: A Video Demonstration
In a recent video demonstration, the capabilities of x64dbg, a powerful reverse engineering tool, are showcased through the unpacking of a complex 4-stage malware sample. This malware is notably obfuscated using SmartAssembly, which necessitates a detailed approach to analysis.
Stages of the Unpacking Process
The unpacking process is divided into multiple stages, each performing specific functions critical for the successful extraction of the malicious payload.
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First Stage: The unpacking process utilizes a simple XOR algorithm for data decryption, laying the groundwork for the subsequent stages.
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Second Stage: Involves a .NET executable named “Zen,” which plays a pivotal role in the unpacking process.
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Third Stage: Introduces another .NET executable, “AProject,” responsible for unpacking a compressed payload. This payload is injected into a child process through a technique known as RunPE, which employs process hollowing.
This method involves several API calls, including GetThreadContext, UnmapViewOfSection, WriteProcessMemory, SetThreadContext, and ResumeThread. During the analysis, breakpoints can be strategically set on API functions like WriteProcessMemory to assist in pinpointing the location of payloads within memory.
Payload Extraction and Analysis
The size of the payload is calculated by identifying the end of the memory page and subtracting the starting address of the payload, allowing for precise memory management. x64dbg’s “save data” command is utilized for dumping memory, enabling the analyst to extract and validate the payload effectively. The final identified payload is a stealer identified as “Pony.”
The video emphasizes the importance of error handling techniques in scripts and iterative testing processes to ensure robust debugging. Additionally, manual unpacking techniques are integrated into x64dbg scripts, enhancing accuracy and repeatability in analysis.
The scripting capabilities of x64dbg are highlighted as a means to automate repetitive tasks, such as setting breakpoints, calculating memory ranges, and saving payloads. These automated scripts significantly enhance the debugging and reverse engineering workflows, providing a systematic approach to malware analysis.
Resources and Community Engagement
The find command within x64dbg can be utilized to locate specific instructions in memory, further streamlining the analysis process. For those new to malware analysis, a Udemy course is mentioned, designed for beginners seeking to understand the fundamentals of this field.
The video also provides links to x64dbg script documentation and an unpacking script, offering viewers additional resources for their analysis endeavors. Those interested in the sample used in the demonstration can access it as a ZIP archive, requiring the password “infected” to unpack.
Overall, this demonstration underscores the power of scripting in x64dbg, allowing for consistent replication of analysis steps and documentation of unpacking processes, which is crucial for knowledge sharing within the cybersecurity community. The creator encourages viewers to follow them on social media and offers support for their educational efforts.
Original Source: Watch Video on YouTube
