The ‘-A’ option in Nmap, is a command line flag that stands for “Aggressive Scan”. This option is typically used to detect operating systems, services, application versions, script scanning, and traceroute. Essentially, it enables additional advanced and aggressive options to offer a more comprehensive scan, in an attempt to discern more information about a network host.
According to Nmap Network Scanning: The Official Nmap Project Guide to Network Discovery and Security Scanning, -A enables both OS detection (-O) and version detection (-sV), as well as script scanning (-sC) and traceroute (—traceroute) (Fyodor, 2009). This means that instead of manually inputting all of these commands, a user can simply use the -A option to implement all of them at once.
There are, of course, other scan options available in Nmap, and for a complete network analysis, they might be implemented alongside the -A option. However, the -A option is particularly powerful due to its multiplicity of functions.
An example use of the -A option, provided by StationX, a cyber security knowledge platform, might be: “nmap -A 192.168.1.1” (Nicholas, 2018). In this command, ‘-A’ registers as the “Aggressive Scan” option, and ’192.168.1.1’ signifies the IP address of the host you’re scanning. The output from this command would usually give a user a significant amount of information about the host, including its operating system and versions, running services, and more, depending on the network configurations and security controls in place.
Importantly, like with all network scanning and penetration testing tools, ethical and legal considerations apply when using Nmap. The -A option, due to its aggressive and probing nature, should be used responsibly, only on network hosts to which users have authorized access or proper permission for such aggressive scanning.
To summarize, the -A option in Nmap is an advanced scan flag that initiates a variety of rich data scans. It is an efficient, time-saving option that combines multiple scan types into a singular command. This can provide comprehensive insights to users about their network hosts, which in turn can help to identify potential vulnerabilities which need addressing, thereby contributing to a more secure network infrastructure.
Sources:
Fyodor. (2009). Nmap Network Scanning: The Official Nmap Project Guide to Network Discovery and Security Scanning.
Nicholas, P. (2018). Nmap: Basic to Advance. Stationx.net.
