Malware Analysis 101: Techniques & Tools

Malware analysis is an essential cybersecurity practice to examine malicious software to uncover its purpose, functionality, and potential impact on targeted systems. This knowledge can then be used to develop effective countermeasures and security solutions.

Malware analysis techniques can be broadly categorized into two groups: a static and dynamic analysis. In this article, we will dive into the depths of these techniques and explore their nuances.

1. Static Analysis

Static analysis is the examination of a malware sample without executing it. This technique allows analysts to gather essential information about the malware without the risk of activating its payload or alerting the attacker.

Static analysis techniques include:

1.1 File Signature Analysis

File signature analysis involves scanning the malware sample against a database of known file signatures, also known as hashes.

Analysts can identify known malware by comparing the hash values of the sample to those in the database. This is a quick and effective technique to detect known malware, but it may not identify new or heavily obfuscated variants.

1.2 Strings Analysis

Analysts can gain valuable insights into its functionality by examining the human-readable strings embedded within the malware binary. Strings analysis can reveal URLs, IP addresses, file names, and other helpful information. However, this technique is limited when dealing with encrypted or obfuscated strings.

1.3 Disassembly and Decompilation

Disassembly is the process of converting machine code into assembly language, while decompilation translates the assembly code into a higher-level language such as C or C++. These techniques help analysts understand the malware's functionality and uncover potential vulnerabilities in the code. Reverse engineering tools such as IDA Pro, Ghidra, and Radare2 can disassemble or decompile malware.

1.4 Control Flow Analysis

Control flow analysis is a technique used to study the sequence of operations performed by the malware. Analysts can understand the malware's decision-making process and identify potential branching points or loops. Analysts can visualize the malware's structure and better comprehend its logic by creating control flow graphs.

2. Dynamic Analysis

Dynamic analysis involves executing the malware in a controlled environment to observe its behaviour and interactions with the system. This technique allows analysts to study the real-time behaviour of the malware and gain insights into its capabilities. Dynamic analysis techniques include:

2.1 Sandbox Analysis

A sandbox is an isolated environment where analysts can safely execute malware without affecting the host system. By monitoring the malware's interactions with the system, analysts can study its behaviour and gather valuable information such as network communications, file system modifications, and registry changes. Popular sandbox solutions include Cuckoo Sandbox, Joe Sandbox, and FireEye's Dynamic Threat Intelligence.

2.2 Debugging

Debugging is stepping through the malware's execution, allowing analysts to monitor its behaviour at a granular level. Using debuggers like OllyDbg or WinDbg, analysts can set breakpoints, manipulate the execution flow, and inspect memory contents, thereby gaining a deeper understanding of the malware's functionality and possible weaknesses.

2.3 Network Traffic Analysis

Malware often communicates with command-and-control (C2) servers to receive instructions, exfiltrate data, or download additional payloads.

Analysts can identify the malware's communication patterns by analyzing network traffic using tools like Wireshark or NetworkMiner, uncovering C2 infrastructure, and potentially intercepting valuable information.

Popular Tools and Techniques

A wide range of tools and techniques are employed in malware analysis. Some of the most popular ones include:

1. Disassemblers and Decompilers: Tools like IDA Pro, Ghidra, and Radare2 help analysts examine the binary code of malware, translating it into a more human-readable format.
2. Debuggers: Debuggers such as OllyDbg, x64dbg, and WinDbg are crucial for dynamic analysis.
3. Sandboxes: Popular sandboxing tools include Cuckoo Sandbox, Joe Sandbox, and FireEye's FLARE VM.
4. Network Analysis Tools: Wireshark and tcpdump are popular tools for capturing and analyzing malware-generated network traffic
5. Behavioural Analysis Tools: Tools like Sysinternals Suite and Process Monitor can track and log changes made by the malware to system files, registry entries, and processes, providing valuable insights into the malware's behaviour.
6. Antivirus and Threat Intelligence Platforms: Solutions like VirusTotal and Malwarebytes can help identify known malware samples and provide context to an analyst's investigation, including information about the malware's capabilities, distribution methods, and threat actors involved.

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Luis Soares

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