FreeBSD 14.1: With user rights one result and with root rights different
[23:13] /home/pal >nmap -Pn 10.44.11.11
Starting Nmap 7.94 ( https://nmap.org ) at 2024-10-23 23:14 EEST
Nmap scan report for 10.44.11.11
Host is up (0.0000050s latency).
All 1000 scanned ports on 10.44.11.11 are in ignored states.
Not shown: 1000 filtered tcp ports (no-response)
Nmap done: 1 IP address (1 host up) scanned in 14.53 seconds
[23:14] /home/pal >sudo nmap -Pn 10.44.11.11
Starting Nmap 7.94 ( https://nmap.org ) at 2024-10-23 23:14 EEST
Nmap done: 1 IP address (0 hosts up) scanned in 2.15 seconds
CharGPT 4o says......
The difference in results between running Nmap as a regular user and as root can be attributed to the way Nmap operates under different privileges:
1. Nmap Behavior with User Rights vs. Root Privileges
• When run as a regular user:
• Nmap can only perform TCP Connect scans (-sT), which rely on establishing full TCP connections with the target ports. This approach is less invasive but generally slower.
• This is why you see responses indicating that the host is up and all ports are filtered.
• When run as root:
• Nmap can perform more advanced scans like SYN scans (-sS), which send SYN packets to ports and rely on TCP stack behavior without establishing a full connection.
• Running as root also allows Nmap to use raw sockets, which provide more flexibility and accuracy in detecting hosts and open ports.
• In this case, the scan reports no hosts up, likely due to firewall or IDS/IPS rules that treat SYN packets differently, or because raw socket behavior is restricted.
2. Possible Reasons for the Discrepancy
• Firewall or IDS/IPS rules: The target network might have firewall rules that block SYN packets but allow full TCP connections, causing the host to appear down during a root scan.
• Host behavior: The host could be configured to respond differently based on the type of packets received. For example, it may block SYN packets but respond to full TCP connections.
• Spoofing or IDS detection: If the network has an intrusion detection system (IDS), it could detect and block Nmap’s SYN scans when run as root, treating it as a potential attack attempt.
• User restrictions: On some systems, specific ICMP messages or responses to SYN packets might be restricted to enhance security, leading to different results between user and root scans.
3. How to Test and Confirm
• Use different Nmap options:
• Try running with -sT explicitly as root to see if results match the non-root scan:
sudo nmap -sT -Pn 10.44.11.11
• Use the -sS option as a regular user, although it might not work without root privileges:
sudo nmap -sS -Pn 10.44.11.11
• Check firewall logs: If possible, check any firewall or IDS logs on the target network to see how it responds to different scan types.
• Use additional debugging:
• Add the -v or -d flag to increase verbosity or debugging output:
sudo nmap -Pn -d 10.44.11.11
4. Workarounds
• Adjust firewall rules on the target network if you have control and are authorized.
• Run Nmap with adjusted timing or spoofing options to attempt to bypass filtering:
sudo nmap -Pn -T4 --source-port 53 10.44.11.11
Summary
The discrepancy is likely due to differences in scan techniques allowed by user vs. root privileges, along with potential firewall rules or IDS mechanisms on the target network.
Thank you for your comprehensive answer
I simply posted your question to ChatGPT 4o.... always be careful with generative AI. It's a very useful tool; but not unlike humans, it can make errors, sometimes great, sometimes small, sometimes not at all.
Like all tools, it's up to the skill of the user of the tools to extract or create value from the tools.