whatportis.com
suggest an edit →

Port 544Kerberos Remote Shell (kshell)

Kerberos Remote shell (kshell) is a network service port traditionally used to provide authenticated command execution between systems in a network using the Kerberos authentication protocol. It enhances the conventional rsh protocol by incorporating secure identity verification, enabling users to remotely execute commands on trusted hosts without transmitting plain credentials. Although designed to improve security, its practical use has diminished in favor of more robust modern alternatives..

inSecurityRemote AccessSystem
transport
tcp

single transport

in transit
cleartext

payload readable on path

assignment
official

registered with iana

risk
2/10

safe

lookups
10,037

rank 464 of 993 · top 47%

Technical Details

what runs on :544

Kerberos Remote Shell (kshell) operates over TCP port 544 and was developed as a Kerberos-secured alternative to the traditional remote shell (rsh) protocol. It integrates Kerberos tickets for authenticating user identities, reducing the risk inherent in plain-text password transmission and mitigating impersonation attacks. By leveraging trusted authentication servers, it allows networked systems in the same Kerberos realm to verify command requests securely.

The kshell protocol's design is modeled closely on rsh, permitting users to execute commands remotely via a shell without initiating an interactive login session. This facilitates automation and scripting across trusted machines within a Kerberos realm, as well as delegated administrative tasks. Unlike SSH, Kerberos Remote Shell relies on network trust and Kerberos tickets rather than establishing encrypted tunnels for all data exchanged.

Given its architecture, kshell generally transmits the actual command output unencrypted, relying solely on Kerberos for authentication. This makes it an improvement over unauthenticated rsh but still less secure than fully encrypted, modern protocols that protect both credentials and content during transmission.

Security Information

exposure of :544

risk score

2/ 10safe

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

security averages 3.8 across 216 ports — this one sits 1.8 below.

in transit

cleartext

credentials and payloads are readable by anyone on path

assignment

official

registered with iana for this service — scanners fingerprint it by number

reachable over

tcp

every listening transport is another surface to filter at the edge

security overview

Common Vulnerabilities:

  • Exposure to man-in-the-middle (MITM) attacks that can intercept unencrypted command output or inject malicious commands.
  • Susceptibility to replay attacks if the Kerberos ticket system is misconfigured or compromised.
  • Lack of data encryption beyond authentication, exposing sensitive data passed during remote shell operations.
  • Potential exploitation via weak Kerberos configurations or credential theft jeopardizing trust relationships.

Common Mitigations:

  • Deprecating use of kshell in favor of encrypted protocols like SSH that secure both authentication and data.
  • Enforcing strong Kerberos realm policies, including ticket lifetimes and renewal restrictions.
  • Implementing strict network segmentation and firewall rules to limit access to port 544.
  • Monitoring authentication logs for suspicious activity indicative of ticket abuse or replay.
  • Disabling legacy rsh and kshell services on systems not requiring them to reduce attack surfaces.

Related Ports

all 216 in security →

the 8 most looked-up other ports in security — 216 ports carry that label.

portservicerisk
:8881Atlasz Secure Servercaution
:443HTTPScaution
:8291Winbox MikroTik Admincaution
:3268Microsoft Global Catalog (GC)caution
:135Microsoft EPMAPcaution
:3128Squid Proxy HTTPcaution
:8080HTTP Alternatecaution
:7000Vuze HTTPS Trackercaution

risk mix of the 8 listed

  • caution100%

3 of 8 encrypted