Windows Executable Loading And Threat Hunting

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From a cybersecurity perspective, understanding how an executable operates in a Microsoft Windows system is crucial for detecting and mitigating threats that target operating system internals. Here’s a more detailed look at each step with an emphasis on the points that are important for a cybersecurity defender to identify anomalies and tools that can help.

Loading the Executable:

This step involves monitoring the file system for any new files or executables. Unusual or unexpected file operations may be a sign of a malicious activity. Tools like Sysmon or File Integrity Monitoring solutions can help here.

Checking File Validity:

Analyzing the file for anomalies in its structure can help identify corrupted or maliciously altered executables. Antivirus and/or endpoint detection and response (EDR) solutions often perform this type of check.

Creating a Process:

Process creation is a significant event on a Windows system from a defender perspective. Monitoring tools can detect new process creation events and record crucial information such as the process name, process ID, and parent process. Unusual parent-child process relationships may indicate malicious activity.

Memory Mapping:

Unexpected or unusual memory mapping (like a high volume of data being loaded into memory, or data being loaded into unusual locations) might indicate a malicious program.

Dynamic Linking:

Some malware uses unusual or suspicious DLLs. Monitoring for DLL loading and checking the reputation of those DLLs can help identify malicious activity. Also, look for signs of “DLL Search Order Hijacking” or “DLL Injection” attacks.

Security Checks:

If a process tries to modify security settings or bypass security checks, it could be an indication of malicious intent.

Thread Creation:

Unusual or unexpected thread creation within a process might indicate a malicious process. For example, if a benign application like calc.exe (calculator on Windows) suddenly starts creating a lot of threads, it might be a sign that it’s been compromised.

Running the Process:

Monitor for processes running from unusual or unexpected locations. For instance, most legitimate Windows processes run from the Windows or Program Files directories, so a Windows process running from the user’s home directory or temp directory would be suspicious.

Process Execution:

Look for unusual behavior such as attempts to access sensitive files, network connections to unexpected locations, or changes to system configuration.

Ending the Process:

A process that repeatedly starts and stops, or one that crashes frequently, might be a sign of a malicious process. Unusual patterns in process termination could also signal that a process is trying to avoid detection. In other words, this could also mean an exploit is at work.

It’s worth noting that no single one of the above signs is a definitive proof of malicious activity, but each one can contribute to a bigger picture. The use of behavioral analysis, heuristics, and threat intelligence can help identify potential threats in real time. Tools like Windows Event Logs, Sysmon, and various Security Information and Event Management (SIEM) solutions can assist in gathering and analyzing this data. Fortunately, the Endpoint threat detection and response (EDR) platforms currently available in the market help to capture a decent amount of process related telemetry which aids in Threat Hunting.

Happy hunting!