Malware Unpacking via Memory Dump and Post-Processing
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Solution Overview
Problem
Malware authors employ sophisticated obfuscation techniques, making packed malware resilient to static analysis by disguising the code's real intention on disk, which hinders effective identification and analysis.
Innovation Solution
A method involving executing a malicious executable in physical memory, creating a memory dump, and performing post-processing operations to generate a new version of the executable, allowing for identification of the initial entry point and enabling further analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If packed malware is used to disguise code intention, then malware detection difficulty increases, but static analysis capability is lost
Solution Approach 1:
The system performs preliminary execution of the packed malware in an isolated environment to trigger the unpacking process before analysis. By executing the malware beforehand and capturing its unpacked state in memory, the system obtains analyzable code without exposing the host system to threats, thus resolving the contradiction between maintaining obfuscation and enabling analysis.
Solution Approach 2:
The system creates a memory copy (memory dump) of the unpacked malware from its runtime state and saves it to disk. This copy preserves the unpacked, analyzable code structure while the original packed executable remains intact. The memory copy can then be subjected to static analysis without requiring the original packed format, thereby recovering static analysis capability while maintaining the protective obfuscation.
2Loss of information
If packed malware is executed to unpack, then code becomes analyzable, but security risk increases
Solution Approach 1:
The system segments the malware analysis process from the host system by using isolated memory spaces and controlled execution environments. The packed malware is executed in a sandboxed manner where its unpacking and malicious actions are contained, preventing spread to the host system. This segmentation allows code analyzability while containing security risks within isolated boundaries.
Solution Approach 2:
The system introduces an intermediary memory capture mechanism that sits between the executing malware and the host system. The memory dump function acts as an intermediary that captures the unpacked code state without allowing the malware to interact with or compromise the host system. This intermediary approach enables code analyzability while blocking the transmission of harmful effects to the main system.
3Loss of information
If memory dump is created after execution, then unpacked code is preserved, but analysis time increases
Solution Approach 1:
The system performs the memory dump operation immediately after the malware executes its unpacking routine but before any further malicious actions occur. This preliminary capture of the unpacked state preserves the complete, analyzable code structure in its native form. By timing the dump operation at this specific moment, the system avoids the need for repeated execution attempts or complex reconstruction processes, thereby reducing overall analysis time while ensuring complete code preservation.
Data Source
AI summary
Provided are methods and systems for unpacking and analyzing malware for purposes of identification and investigation. A malicious executable or an application containing malicious code is executed in sandboxed memory to unpack the executable. The memory is then dumped to disk and one or more post-processing operations are performed to generate a new version of the executable, including identifying an initial entry point of the executable, recreating the relocation table, and recreating the import address table, export table, and other tables of the executable. Various types of analyses, such as static analyses, which could not be performed on the malicious executable, are able to be performed on the new version of the executable.