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EC-Council

312-50V9 · Question #394

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 feature (-O) requires raw socket access, which is only available to root or administrators, causing the scan to quit when run as an unprivileged user.

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

(44 responses)
  • A
    93% (41)
  • B
    5% (2)
  • C
    2% (1)

Why each option

Nmap's OS detection feature (-O) requires raw socket access, which is only available to root or administrators, causing the scan to quit when run as an unprivileged user.

AOS Scan requires root privilegesCorrect

The -O flag triggers Nmap's OS fingerprinting engine, which sends and receives raw TCP/IP packets that require elevated privileges to create. On Linux/Unix systems, raw socket operations are restricted to the root user, so running the command as a non-root user (shown by the standard shell prompt with no '#') causes Nmap to abort with the 'TCP/IP fingerprinting... QUITTING!' error. The fix is to run the command with sudo.

BThe nmap syntax is wrong.

While the flag shown is '-0' (zero) rather than '-O' (letter O), the error message specifically references TCP/IP fingerprinting failure, pointing to a privileges issue rather than a syntax parse error.

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

A host firewall blocking outgoing packets would result in no responses or timeouts, not the specific 'TCP/IP fingerprinting QUITTING' error message that indicates an OS-level privilege denial.

DThis is a common behavior for a corrupted nmap application

A corrupted nmap installation would produce different errors such as missing libraries or segmentation faults, not a consistent privilege-related quit message tied to raw socket creation.

Concept tested: Nmap OS detection root privilege requirement

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

Topics

#Nmap#OS fingerprinting#root privileges#network scanning

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