Authors: | Created: 2021-08-27 | Last update: 2022-08-02
Nmap CheatSheet¶
Common Nmap Commands¶
Aggressive scan, single host, TCP SYN, :
nmap -n -sS -p- -T4 -Pn -A -v 192.168.1.1
Ping Scan - Host discovery in subnet
nmap -sn -v 192.168.0.0/24
Target Specification¶
| Switch | Description | Example |
|---|---|---|
| nmap 192.168.1.1 | Scan a single IP | |
| nmap 192.168.1.1 192.168.2.1 | Scan specific IPs | |
| nmap scanme.nmap.org | Scan a range | |
| nmap scanme.nmap.org | Scan a domain | |
| nmap 192.168.1.0/24 | Scan using CIDR notation | |
| -iL | nmap -iL targets.txt | Scan targets from a file |
| -iR | nmap -iR 100 | Scan 100 random hosts |
| --exclude | nmap --exclude 192.168.1.1 | Exclude listed hosts |
Scan Techniques¶
| Switch | Example | Description |
|---|---|---|
| -sS | nmap 192.168.1.1 -sS | TCP SYN port scan (Default) |
| -sT | nmap 192.168.1.1 -sT | TCP connect port scan (Default without root privilege) |
| -sU | nmap 192.168.1.1 -sU | UDP port scan |
| -sA | nmap 192.168.1.1 -sA | TCP ACK port scan |
| -sW | nmap 192.168.1.1 -sW | TCP Window port scan |
| -sM | nmap 192.168.1.1 -sM | TCP Maimon port scan |
Host Discovery¶
| Switch | Description | Example |
|---|---|---|
| -sL | nmap 192.168.1.1-3 -sL | No Scan. List targets only |
| -sn | nmap 192.168.1.1/24 -sn | Disable port scanning. Host discovery only. |
| -Pn | nmap 192.168.1.1-5 -Pn | Disable host discovery. Port scan only. |
| -PS | nmap 192.168.1.1-5 -PS22-25,80 | TCP SYN discovery on port x.Port 80 by default |
| -PA | nmap 192.168.1.1-5 -PA22-25,80 | TCP ACK discovery on port x.Port 80 by default |
| -PU | nmap 192.168.1.1-5 -PU53 | UDP discovery on port x.Port 40125 by default |
| -PR | nmap 192.168.1.1-1/24 -PR | ARP discovery on local network |
| -n | nmap 192.168.1.1 -n | Never do DNS resolution |
Port Specification¶
| Switch | Description | Example |
|---|---|---|
| -p | nmap 192.168.1.1 -p 21 | Port scan for port x |
| -p | nmap 192.168.1.1 -p 21-100 | Port range |
| -p | nmap 192.168.1.1 -p U:53,T:21-25,80 | Port scan multiple TCP and UDP ports |
| -p | nmap 192.168.1.1 -p- | Port scan all ports |
| -p | nmap 192.168.1.1 -p http,https | Port scan from service name |
| -F | nmap 192.168.1.1 -F | Fast port scan (100 ports) |
| --top-ports | nmap 192.168.1.1 --top-ports 2000 | Port scan the top x ports |
| -p-65535 | nmap 192.168.1.1 -p-65535 | Leaving off initial port in range makes the scan start at port 1 |
| -p0- | nmap 192.168.1.1 -p0- | Leaving off end port in rangemakes the scan go through to port 65535 |
Service and Version Detection¶
| Switch | Description | Example |
|---|---|---|
| -sV | nmap 192.168.1.1 -sV | Attempts to determine the version of the service running on port |
| -sV --version-intensity | nmap 192.168.1.1 -sV --version-intensity 8 | Intensity level 0 to 9. Higher number increases possibility of correctness |
| -sV --version-light | nmap 192.168.1.1 -sV --version-light | Enable light mode. Lower possibility of correctness. Faster |
| -sV --version-all | nmap 192.168.1.1 -sV --version-all | Enable intensity level 9. Higher possibility of correctness. Slower |
| -A | nmap 192.168.1.1 -A | Enables OS detection, version detection, script scanning, and traceroute |
OS Detection¶
| Switch | Description | Example |
|---|---|---|
| -O | nmap 192.168.1.1 -O | Remote OS detection using TCP/IP stack fingerprinting |
| -O --osscan-limit | nmap 192.168.1.1 -O --osscan-limit | If at least one open and one closed TCP port are not found it will not try OS detection against host |
| -O --osscan-guess | nmap 192.168.1.1 -O --osscan-guess | Makes Nmap guess more aggressively |
| -O --max-os-tries | nmap 192.168.1.1 -O --max-os-tries 1 | Set the maximum number x of OS detection tries against a target |
| -A | nmap 192.168.1.1 -A | Enables OS detection, version detection, script scanning, and traceroute |
Timing and Performance¶
| Switch | Description | Example |
|---|---|---|
| -T0 | nmap 192.168.1.1 -T0 | Paranoid (0) Intrusion DetectionSystem evasion |
| -T1 | nmap 192.168.1.1 -T1 | Sneaky (1) Intrusion Detection Systemevasion |
| -T2 | nmap 192.168.1.1 -T2 | Polite (2) slows down the scan to useless bandwidth and use less target machine resources |
| -T3 | nmap 192.168.1.1 -T3 | Normal (3) which is default speed |
| -T4 | nmap 192.168.1.1 -T4 | Aggressive (4) speeds scans; assumes you are on a reasonably fast and reliable network |
| -T5 | nmap 192.168.1.1 -T5 | Insane (5) speeds scan; assumes you are on an extraordinarily fast network |
| -------- | -------- | ------------------------------------------------------------------------------------------- |
| --host-timeout | 1s; 4m; 2h | Give up on target after this long |
| --min-rtt-timeout/max-rtt-timeout/initial-rtt-timeout | 1s; 4m; 2h | Specifies probe round trip time |
| --min-hostgroup/max-hostgroup <size | 50; 1024 | Parallel host scan group sizes |
| --min-parallelism/max-parallelism | 10; 1 | Probe parallelization |
| --scan-delay/--max-scan-delay | 20ms; 2s; 4m; 5h | Adjust delay between probes |
| --max-retries | 3 | Specify the maximum number of port scan probe retransmissions |
| --min-rate | 100 | Send packets no slower than |
| --max-rate | 100 | Send packets no faster than |
NSE Scripts¶
| Switch | Description | Example |
|---|---|---|
| -sC | nmap 192.168.1.1 -sC | Scan with default NSE scripts. Considered useful for discovery and safe |
| --script default | nmap 192.168.1.1 --script default | Scan with default NSE scripts. Considered useful for discovery and safe |
| --script | nmap 192.168.1.1 --script=banner | Scan with a single script. Example banner |
| --script | nmap 192.168.1.1 --script=http* | Scan with a wildcard. Example http |
| --script | nmap 192.168.1.1 --script=http,banner | Scan with two scripts. Example http and banner |
| --script | nmap 192.168.1.1 --script "not intrusive" | Scan default, but remove intrusive scripts |
| --script-args | nmap --script snmp-sysdescr --script-args snmpcommunity=admin 192.168.1.1 | NSE script with arguments |
Useful NSE Script Examples¶
| Command | Description |
|---|---|
| nmap -Pn --script=http-sitemap-generator scanme.nmap.org | http site map generator |
| nmap -n -Pn -p 80 --open -sV -vvv --script banner,http-title -iR 1000 | Fast search for random web servers |
| nmap -Pn --script=dns-brute domain.com | Brute forces DNS hostnames guessing subdomains |
| nmap -n -Pn -vv -O -sV --script smb-enum,smb-ls,smb-mbenum,smb-os-discovery,smb-s,smb-vuln,smbv2 -vv 192.168.1.1 | Safe SMB scripts to run |
| nmap --script whois* domain.com | Whois query |
| nmap -p80 --script http-unsafe-output-escaping scanme.nmap.org | Detect cross site scripting vulnerabilities |
| nmap -p80 --script http-sql-injection scanme.nmap.org | Check for SQL injections |
Firewall / IDS Evasion and Spoofing¶
| Switch | Description | Example |
|---|---|---|
| -f | nmap 192.168.1.1 -f | Requested scan (including ping scans) use tiny fragmented IP packets. Harder for packet filters |
| --mtu | nmap 192.168.1.1 --mtu 32 | Set your own offset size |
| -D | nmap -D 192.168.1.101,192.168.1.102, 192.168.1.103,192.168.1.23 192.168.1.1 | Send scans from spoofed IPs |
| -D | nmap -D decoy-ip1,decoy-ip2,your-own-ip,decoy-ip3,decoy-ip4 remote-host-ip | Above example explained |
| -S | nmap -S www.microsoft.com www.facebook.com | Scan Facebook from Microsoft (-e eth0 -Pn may be required) |
| -g | nmap -g 53 192.168.1.1 | Use given source port number |
| --proxies | nmap --proxies http://192.168.1.1:8080, http://192.168.1.2:8080 192.168.1.1 | Relay connections through HTTP/SOCKS4 proxies |
| --data-length | nmap --data-length 200 192.168.1.1 | Appends random data to sent packets |
Example IDS Evasion command¶
nmap -f -t 0 -n -Pn –data-length 200 -D 192.168.1.101,192.168.1.102,192.168.1.103,192.168.1.23 192.168.1.1
Output¶
| Switch | Description | Example |
|---|---|---|
| -oN | nmap 192.168.1.1 -oN normal.file | Normal output to the file normal.file |
| -oX | nmap 192.168.1.1 -oX xml.file | XML output to the file xml.file |
| -oG | nmap 192.168.1.1 -oG grep.file | Grepable output to the file grep.file |
| -oA | nmap 192.168.1.1 -oA results | Output in the three major formats at once |
| -oG - | nmap 192.168.1.1 -oG - | Grepable output to screen. -oN -, -oX - also usable |
| --append-output | nmap 192.168.1.1 -oN file.file --append-output | Append a scan to a previous scan file |
| -v | nmap 192.168.1.1 -v | Increase the verbosity level (use -vv or more for greater effect) |
| -d | nmap 192.168.1.1 -d | Increase debugging level (use -dd or more for greater effect) |
| --reason | nmap 192.168.1.1 --reason | Display the reason a port is in a particular state, same output as -vv |
| --open | nmap 192.168.1.1 --open | Only show open (or possibly open) ports |
| --packet-trace | nmap 192.168.1.1 -T4 --packet-trace | Show all packets sent and received |
| --iflist | nmap --iflist | Shows the host interfaces and routes |
| --resume | nmap --resume results.file | Resume a scan |
Helpful Nmap Output examples¶
Scan for web servers and grep to show which IPs are running web servers
nmap -p80 -sV -oG - --open 192.168.1.1/24 | grep open
Generate a list of the IPs of live hosts
nmap -iR 10 -n -oX out.xml | grep "Nmap" | cut -d " " -f5 > live-hosts.txt
Append IP to the list of live hosts
nmap -iR 10 -n -oX out2.xml | grep "Nmap" | cut -d " " -f5 >> live-hosts.txt
Compare output from nmap using the ndif
ndiff scanl.xml scan2.xml
Convert nmap xml files to html files
xsltproc nmap.xml -o nmap.html
Reverse sorted list of how often ports turn up
grep " open " results.nmap | sed -r 's/ +/ /g' | sort | uniq -c | sort -rn | less
Miscellaneous Options¶
| Switch | Description | Example |
|---|---|---|
| -6 | nmap -6 2607:f0d0:1002:51::4 | Enable IPv6 scanning |
| -h | nmap -h | nmap help screen |
Other Useful Nmap Commands¶
Discovery only on ports x, no port scan
nmap -iR 10 -PS22-25,80,113,1050,35000 -v -sn
Arp discovery only on local network, no port scan
nmap 192.168.1.1-1/24 -PR -sn -vv
Traceroute to random targets, no port scan
nmap -iR 10 -sn -traceroute
Query the Internal DNS for hosts, list targets only
nmap 192.168.1.1-50 -sL --dns-server 192.168.1.1