In Nmap, the -sC flag is used to perform a default script scan. This flag invokes the Nmap Scripting Engine (NSE) to run a set of standard scripts against the target, aiming to detect common vulnerabilities and gather additional information.
How It Works?
When you execute Nmap with the -sC option, it automatically runs scripts from the "default" category. These scripts are designed to perform various tasks, such as:
- Service Detection: Identifying the versions of services running on open ports.
- OS Detection: Determining the operating system of the target machine.
- Vulnerability Detection: Checking for common vulnerabilities in services.
- Additional Information Gathering: Collecting data like supported SSL/TLS versions or available SMB shares.
Usage Example
To perform a default script scan on a target with IP address 192.168.1.1, you would use:
nmap -sC 192.168.1.1
Combining with Other Flags
The -sC flag is often combined with other options to enhance the scan's effectiveness:
nmap -sC -sV 192.168.1.1
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Aggressive Scan (-A): Enables OS detection, version detection, script scanning, and traceroute all at once.
nmap -A 192.168.1.1
Note: The -A flag includes the default script scan (-sC) as part of its operations.
Use Cases
- Network Security Audits: Quickly assess systems for common vulnerabilities.
- Inventory Management: Gather detailed information about devices and services on a network.
- Troubleshooting: Identify misconfigurations or outdated services that may pose security risks.
Considerations
- Intrusiveness: Some scripts may be intrusive. Ensure you have proper authorization before scanning.
- Performance: Running multiple scripts can increase scan time and resource usage.
For a comprehensive list of available scripts and their categories, refer to the Nmap Scripting Engine documentation.
