CHFI (312-49) Digital Forensics Simulation

Investigation Scenario

During a malware-analysis investigation in San Jose, California, an enterprise security team isolated a suspicious Windows executable (`invoice_update.exe`) delivered via a phishing campaign. The incident response team has provided the digital forensics unit with a preserved copy of the binary.

The investigator must perform static analysis to understand the binary's capabilities, specifically examining the functions it imports from external libraries (DLLs), without risking execution in a live environment. Understanding these imports will help determine if the malware possesses networking capabilities, file manipulation routines, or evasion tactics.

Evidence Collected

Question

Question: In a malware-analysis investigation in San Jose, California, an analyst is performing static analysis on a suspicious Windows executable. The analyst wants to view the list of functions that the executable imports from external libraries (DLLs). Which tool should the analyst use?

Expert Analysis

1. What evidence shows:

The forensic analyst is handling a suspicious Windows executable (`.exe`). Because dynamic analysis is hindered by anti-analysis behaviors, the investigator must rely on static analysis. The primary goal is to map the binary's potential capabilities by extracting the Import Address Table (IAT) without executing the payload.

2. Identify forensic stage:

Examination & Analysis phase. Specifically, the static malware analysis sub-phase, where binary structures are evaluated to form a hypothesis about the malware's behavior.

3. Why correct answer is correct (A):

A. PE Explorer: PE Explorer is a dedicated static analysis tool designed to inspect the inner workings of Windows 32-bit executables (Portable Executable format). It allows analysts to view file headers, section properties, and crucially, the export and import tables. By examining the imports, an investigator can see exactly which API functions the executable requests from the OS via DLLs (e.g., `ws2_32.dll` for networking, `kernel32.dll` for process manipulation).

4. Why others are wrong:

• B. Wireshark: This is a network protocol analyzer. It is used during dynamic analysis to capture and analyze packet traces over a network interface. It cannot analyze the internal structure of an executable file.
• C. Autopsy: Autopsy is a digital forensics platform primarily used for analyzing disk images, navigating file systems, and recovering deleted files. While it is a forensic suite, it is not specialized for parsing deep PE header structures like the IAT.
• D. FTK Imager: This is a data preview and imaging tool used primarily during the Collection and Preservation phases to create forensic disk and memory images. It does not parse executable structural data.

5. Real-world forensic action:

The investigator would load the isolated `invoice_update.exe` into a PE analysis tool like PE Explorer, CFF Explorer, or PEStudio within a secure, air-gapped forensic workstation. The analyst would document calls to suspicious APIs such as `VirtualAllocEx` and `CreateRemoteThread` to hypothesize process injection techniques before continuing the investigation.