As a Security Operations Center (SOC) analyst, understanding the fundamental processes and directories in Windows is crucial to detecting potential threats and investigating security incidents. From system files to event logs and service control, each component serves as a piece in the puzzle of the system’s security landscape. This blog post will delve into the importance of various Windows directories and processes and how they can be utilized by SOC analysts to mitigate threats and respond effectively to incidents.
Important Windows Directories
System32
The System32 directory is one of the most critical directories in a Windows operating system. Located within the Windows directory, System32 holds a vast number of crucial files and executables that are essential for the proper functioning of the Windows operating system. These files include system utilities, device drivers, dynamic-link libraries (DLLs), and system executables.
Given its importance to the system, System32 is a directory that malware often targets or uses to hide malicious activities. For instance, malware may replace or modify existing files in this directory or add new malicious files that mimic legitimate ones.
Program Files
The Program Files directory is where applications are typically installed on a Windows system. Each installed application gets its own subdirectory under Program Files, where it stores its executable files, DLLs, and other related files.
Monitoring the Program Files directory can provide valuable insights into the software installed on a system. Unusual or unexpected changes in this directory, such as the addition of unknown software or modification of existing software, could indicate a potential security incident.
AppData
The AppData directory is a user-specific directory that stores application data for each user on a Windows system. The AppData directory contains three subdirectories: Roaming, Local, and LocalLow. The Roaming directory is used for data that can move with a user profile between different machines, like configuration settings. The Local and LocalLow directories are used for data that stays on a single machine, such as temporary files.
Malware often exploits AppData to store malicious files because it’s user-specific and often overlooked during manual investigations. Therefore, it’s crucial for SOC analysts to include AppData in their routine security checks.
Temp
The Temp directory, as the name suggests, is used for storing temporary files. These files are typically created by applications for temporary use during their execution, and by the system for tasks like software installation.
While the Temp directory is a necessary part of the operating system, it can also be exploited by malware. Malicious programs often use the Temp directory to store and execute malicious files, as they can often do so without raising suspicions.
Services
The Services directory isn’t a standard directory like the others but is referring to the set of services running on a Windows system. Services in Windows are background processes that usually start up with the system and run continuously, independently of user sessions. They perform essential tasks like managing network connections, handling system updates, and executing scheduled tasks.
Services are configured and managed through the Windows Registry and the Services Control Manager. Since services often run with high-level privileges, they’re a common target for malware. Malicious actors may create malicious services or modify existing ones to execute malicious tasks. As such, SOC analysts need to keep a close eye on the services configured on a system.
Windows Event Logs
Windows event logs provide a wealth of information about system events, such as application crashes, security events, and system errors. They serve as a crucial resource for SOC analysts when detecting potential security incidents and conducting subsequent investigations. By analyzing event logs, analysts can gain insights into the nature of the incident, the affected components, and potentially even the attacker’s objectives.
Important Windows Processes
Svchost.exe
The svchost.exe file is an integral part of the Windows operating system and is responsible for hosting a multitude of essential Windows services. These services are loaded from dynamic-link library (DLL) files instead of EXE files, with svchost.exe providing a shell for these services to run.
Since a variety of services run under svchost.exe, you will often find multiple instances of this process running on your system. This is completely normal and allows Windows to effectively manage and run these different services.
From a security perspective, due to its ubiquity and importance, svchost.exe is often a prime target for malware. Malware can mimic this process or inject malicious code into legitimate svchost.exe processes. Therefore, it’s important for SOC analysts to be aware of the typical behavior of svchost.exe and be able to identify suspicious activity associated with it.
Services.exe
The services.exe process, also known as the Service Control Manager (SCM), is another essential part of the Windows operating system. It is responsible for managing system services, including starting, stopping, and interacting with services.
Services.exe is a system process that is started by the system itself and is not directly linked to any user-initiated action. It launches at system start and continues to run as long as the system is on.
The SCM provides a communication interface that allows programs to interact with services. It receives service requests from user applications, then interacts with the corresponding service to fulfill the request.
Similar to svchost.exe, services.exe is a common target for malware due to its critical role in the system. Malicious software can mimic this process or inject code into it to gain system-level privileges, hide its activities, or disrupt system services. As such, SOC analysts should monitor this process closely for any unusual behavior.
Windows Registry: HKLM\SYSTEM\CurrentControlSet\Services
This registry key contains information about the system services installed on the system. By understanding and monitoring changes to this key, SOC analysts can detect potential malicious services and investigate them further.
Conclusion
In-depth knowledge of Windows directories and processes is an invaluable asset for SOC analysts. It enables them to swiftly locate potential malware, investigate security incidents, and respond effectively to threats. Moreover, continuous monitoring of Windows security events and logs provides valuable insights into potential threats and aids analysts in detecting and responding to them in a timely manner. By mastering these fundamental elements of the Windows operating system, SOC analysts can enhance their ability to safeguard their organizations against cyber threats.