312-50V10 · 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 xx
The correct answer is A. OS Scan requires root privileges. Nmap's OS detection feature (-O flag) requires root or administrator privileges because it must craft and send raw packets, which is a privileged operation on Unix-based systems.
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
(57 responses)- A88% (50)
- B4% (2)
- C7% (4)
- D2% (1)
Why each option
Nmap's OS detection feature (-O flag) requires root or administrator privileges because it must craft and send raw packets, which is a privileged operation on Unix-based systems.
The -O flag enables OS fingerprinting by sending specially crafted raw TCP/IP packets and analyzing responses, an operation that requires raw socket access. On Linux and Unix systems, raw socket creation is restricted to the root user, so running the scan as a non-root user causes Nmap to abort with the 'QUITTING!' error shown in the question.
The Nmap syntax is functionally correct - the -T4 timing flag and CIDR target range are valid; the only issue is the privilege level of the user running the command.
The error message shown is a local privilege error from Nmap itself, not a firewall block - a host firewall would produce a different behavior such as filtered or dropped packets.
The 'QUITTING!' message is standard Nmap output for insufficient privileges and does not indicate application corruption.
Concept tested: Nmap OS detection root privilege requirement
Source: https://nmap.org/book/man-os-detection.html
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