To guarantee the security and integrity of your network's timekeeping architecture, it is essential to count time servers and look for configuration errors. The following resources, methods, and helpful guidance will assist you in doing so:
Tools for Enumerating Time Servers
1. ntpdate -q or ntpdate -qv (with verbosity)
While primarily used for querying NTP servers, it can help in identifying reachable NTP servers by IP or domain name. Be cautious with firewall rules.
2. nmap with NTP Scripting Engine (NSE)
- Discovery: Use nmap -sU -p 123 <target_IP_range> to scan for UDP port 123, which NTP uses.
- NSE Script for NTP Info: Utilize nmap --script=ntp-info <target_IP> to gather more detailed information about the NTP server's configuration.
- OpenNTPD Tools or Similar Daemon-Specific Tools: If you're working within a *BSD environment or using OpenNTPD, leveraging its built-in tools for server discovery might be beneficial.
Tools for Checking Misconfigurations
1. ntpq and ntpdc Commands
- ntpq -p <NTP_Server_IP>: Shows peer information, which can indicate if the server is open to anyone.
- ntpdc -c sysinfo <NTP_Server_IP>: Provides system info. If this works without authentication, it might indicate a misconfiguration.
2. NTPSec Tools
ntpsec suite, specifically tools like ntpviz or sleuth, can help in analyzing the security posture of NTP servers, including identifying potential misconfigurations.
3. Scan and Audit Tools like OpenVAS or Nessus:
While broader in scope, these vulnerability scanners often include checks for common NTP misconfigurations and vulnerabilities.
Example Script for Basic NTP Server Enumeration:
#!/bin/bash
# Target network range
TARGET_NETWORK="192.168.1.0/24"
# Nmap command to find NTP servers
nmap -sU -p 123 $TARGET_NETWORK -oG ntp_servers.txt
# Parse output to get IPs
ntp_servers=$(cat ntp_servers.txt | grep "/open/" | cut -d' ' -f2)
# For each NTP server, gather more info
for server in $ntp_servers; do
echo "Gathering info for $server..."
nmap --script=ntp-info $server
done
