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EC-Council

312-50V11 · Question #524

Jack was attempting to fingerprint all machines in the network using the following Nmap syntax: invictus@victim_server:~$ nmap -T4 -0 10.10.0.0/24 TCP/IP fingerprinting (for OS scan) xxxxxxx xxxxxx…

The correct answer is A. OS Scan requires root privileges. Nmap's OS detection flag (-O) requires raw socket access, which is only available to root or administrator-level users on Unix/Linux systems.

Scanning Networks

Question

Jack was attempting to fingerprint all machines in the network using the following Nmap syntax:

invictus@victim_server:~$ nmap -T4 -0 10.10.0.0/24 TCP/IP fingerprinting (for OS scan) xxxxxxx xxxxxx xxxxxxxxx. QUITTING! Obviously, it is not going through. What is the issue here?

Options

  • AOS Scan requires root privileges
  • BThe nmap syntax is wrong.
  • CThe outgoing TCP/IP fingerprinting is blocked by the host firewall
  • DThis is a common behavior for a corrupted nmap application

How the community answered

(50 responses)
  • A
    94% (47)
  • C
    2% (1)
  • D
    4% (2)

Why each option

Nmap's OS detection flag (-O) requires raw socket access, which is only available to root or administrator-level users on Unix/Linux systems.

AOS Scan requires root privilegesCorrect

Nmap OS scan uses raw TCP/IP packet crafting and inspection to fingerprint remote operating systems, which requires elevated privileges to access raw sockets. On Linux/Unix, this means the process must run as root. The exact error 'TCP/IP fingerprinting (for OS scan) QUITTING!' is the standard nmap output when it lacks the necessary root privileges to perform the scan.

BThe nmap syntax is wrong.

The nmap syntax itself is structurally valid - -T4 sets the timing template and -O triggers OS detection against a /24 subnet, which is correct usage.

CThe outgoing TCP/IP fingerprinting is blocked by the host firewall

A host firewall blocking outgoing traffic would produce timeout or filtered results per host, not an immediate privilege-related 'QUITTING' error before scanning begins.

DThis is a common behavior for a corrupted nmap application

A corrupted nmap installation would produce irregular or undefined errors, not the specific and well-known privilege-denial message shown for OS scan attempts.

Concept tested: Nmap OS scan root privilege requirement

Source: https://nmap.org/book/man-os-detection.html

Topics

#Nmap#OS fingerprinting#root privileges#TCP/IP fingerprinting

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