TCP Port 135 – epmap

About TCP Port 135

Port 135 is registered with the Internet Assigned Numbers Authority (IANA) for epmap. The IANA description reads: ‘DCE endpoint resolution’. This port appears in 10 IDS rules and does not have notable malware activity indicators in our data.

IDS Rule References

10 IDS / security rules reference TCP port 135. Treat that number as context, not a danger score. Many detection rules are written against groups of ports rather than one service, web ports especially, so common web alternate ports inherit large counts while genuinely sensitive services can show few rules or none. Presence in IDS rules does not mean traffic on this port is malicious.

Rule categories (top 5): protocol-command-decode (3), attempted-admin (3), attempted-dos (2), attempted-recon (1), misc-activity (1).

Sample rule descriptions for TCP port 135:

• NETBIOS DCERPC NCACN-IP-TCP srvsvc NetrShareEnum null policy handle attempt
• SERVER-OTHER Winnuke attack
• NETBIOS DCERPC invalid bind attempt
• OS-WINDOWS DCERPC NCACN-IP-TCP lsass DsRolerUpgradeDownlevelServer overflow attempt
• OS-WINDOWS DCERPC NCACN-IP-TCP ISystemActivator CoGetInstanceFromFile attempt

Data Sources

This information is compiled from: IANA Service Name and Transport Protocol Port Number Registry, Emerging Threats Open Ruleset (BSD 2-Clause / GPLv2 per SID range), and Snort Community Rules (GPLv2).