Port 9561Network Time System

The Network Time System is an application that synchronizes time across multiple systems within a local enterprise environment or over the internet. Utilizing both TCP and UDP protocols, it ensures accurate timekeeping by acting as a centralized server, distributing precise timestamps to connected devices. This aids in event logging, security audits, and ensuring coordinated operations across distributed environments..

transport
tcp · udp

2 transports registered

in transit
cleartext

payload readable on path

assignment
unofficial

used by convention

risk
2/10

safe

lookups
8,299

rank 603 of 993 · top 61%

Technical Details

what runs on :9561

The Network Time System Server typically functions similarly to an NTP (Network Time Protocol) server, facilitating the distribution of synchronized time data to multiple client systems within a network domain. It operates over both TCP and UDP on port 9561, allowing clients flexibility in communication protocols based on network architecture and firewall configurations.

Internally, the system manages timestamps sourced from authoritative external clocks or internal oscillators, then provides this information to clients ensuring that timestamps are consistent across devices. This is crucial for event correlation, transaction ordering, and minimizing clock drift, especially in environments like financial institutions where timing precision is critical.

Deployment scenarios often involve the Network Time System server being connected to an enterprise’s internal network, occasionally with access to internet-based time sources for improved accuracy. The server handles requests from clients periodically or upon client system startup, and may offer authentication mechanisms to ensure authorized usage.

Security Information

exposure of :9561

risk score

2/ 10safe

routine exposure. this port is rarely the way in on its own — keep it patched and logged and move on.

network services averages 3.9 across 604 ports — this one sits 1.9 below.

in transit

cleartext

credentials and payloads are readable by anyone on path

assignment

unofficial

used by convention, not registered — what answers here varies by deployment

reachable over

tcp · udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

Common vulnerabilities associated with time synchronization services like Network Time System include:

  • Amplification attacks via UDP, where attackers use the server to magnify DDoS attack volumes.
  • Spoofed responses, where a malicious actor injects incorrect time data leading to desynchronization.
  • Unauthorized access, potentially allowing manipulation of system clocks which can affect logs and security controls.

Mitigations include:

  • Restricting server access to only trusted network segments via firewalls.
  • Implementing access control and authentication for clients.
  • Employing anti-spoofing measures such as signing time responses or using encrypted communication.
  • Keeping the software updated to patch known vulnerabilities.
  • Monitoring network traffic for anomalous behavior indicative of exploitation attempts.

the 8 most looked-up other ports in network services — 604 ports carry that label.

risk mix of the 8 listed

  • caution100%

0 of 8 encrypted