During my technical interview at Protergo, I had the opportunity to showcase my skills in malware analysis. This blog post will take you through the exciting journey of dissecting a suspicious file using Cuckoo Sandbox, a powerful tool for both static and dynamic analysis.
Step-by-Step Malware Analysis with Cuckoo Sandbox
Step 1: Unpacking the Suspect
After downloading the sample file, I unzipped it to reveal its contents. This initial step allows us to see what’s lurking inside the archive.
cuckoo@cuckoo-sandbox:~$ cd Documents
cuckoo@cuckoo-sandbox:~$ unzip PowerShellScript.zip
Step 2: Setting Up a Safe Environment
To create a safe environment for the analysis, I fired up a separate virtual machine running Windows. This isolated space ensures that the malware can’t wreak havoc on my actual system. It’s like having a controlled experiment to observe the malware’s behavior!
cuckoo@cuckoo-sandbox:~$ sudo virtualbox
Step 3: Launching Cuckoo Sandbox
With the virtual machine prepped, I launched the Cuckoo Sandbox tools. This versatile software provides a user-friendly interface to conduct both static and dynamic analysis of the malware. Think of it as a magnifying glass and a microscope combined, allowing us to see the malware from different angles.
cuckoo@cuckoo-sandbox:~$ sudo cuckoo -d
Step 4: Running the Local Web Server
To access Cuckoo Sandbox’s interface conveniently, I also ran a local web server. This lets me analyze the malware from the comfort of a web browser, just like browsing any other website.
cuckoo@cuckoo-sandbox:~$ sudo cuckoo web runserver
Step 5: Accessing the Sandbox Interface
After a successful launch, I was greeted by the Cuckoo Sandbox interface. It’s the mission control center from where we’ll be dissecting the malware’s secrets.
Step 6: Importing the Sample for Analysis
The next step was crucial. I imported the suspicious file into Cuckoo Sandbox for a thorough examination. This is like putting the malware under the scanner to see what makes it tick.
Step 7: Observing Malware Behavior
Cuckoo Sandbox then did its magic. It executed the malware within a simulated environment inside the Windows virtual machine. This lets us observe how the malware behaves in a controlled setting, mimicking a real-world attack scenario.
Step 8: Reviewing the Analysis Report
Once the malware finished its execution, Cuckoo Sandbox presented the analysis report. This report is like a treasure trove of information, revealing the malware’s characteristics and potential threats.
Key Findings
Malware Signatures
The report highlighted the malware’s distinctive signatures. These signatures are like fingerprints, helping us identify the type of malware we’re dealing with and potentially link it to known threats.
Screenshots of Activity
Scrolling down the report, I found screenshots capturing the virtual machine’s activities during the malware execution. These screenshots provide valuable visual evidence of the malware’s actions.
Static Analysis Results
The initial static analysis, which examines the code without actually running it, didn’t yield any significant results. This often happens with encrypted malware, where the malicious code is hidden from plain sight.
Strings Analysis
However, the strings analysis proved more fruitful. Here, I discovered strings associated with keyloggers. Keyloggers are malicious programs designed to steal your keystrokes, potentially revealing passwords, login credentials, and other sensitive information you might type. This finding suggested that the malware aimed to spy on the target user’s activities.
Missing Behavioral Data
Unfortunately, the behavioral analysis section of the report lacked data. This page typically details the malware’s interactions with the system, such as accessing the registry, manipulating files, or communicating over the network. The absence of data in this section could be due to various reasons, requiring further investigation.
Conclusion: Keylogger Confirmed
The analysis using Cuckoo Sandbox revealed several key points. The presence of specific signatures and the discovery of keylogger-related strings strongly suggested that we were dealing with a malicious program designed to steal user data.
Furthermore, the potential exfiltration of captured data to an attacker’s email address highlighted the urgency to take action.