TCP Port 9581

About TCP Port 9581

Port 9581 sits outside of IANA’s formally registered assignments. Ports in this numerical range can be assigned by IANA but this specific port has no current registration. It is referenced in 2 IDS rules and exhibits low malware activity indicators. Ports outside formal IANA assignment are commonly used by malware authors and security tooling.

IDS Rule References

2 IDS / security rules reference TCP port 9581. Presence in IDS rules does not mean traffic on this port is malicious. These are patterns security tools monitor.

Rule categories (top 1): command-and-control (2).

Sample rule descriptions for TCP port 9581:

• ET MALWARE Win32/Recslurp.D C2 Request (no alert)
• ET MALWARE Win32/Recslurp.D C2 Response

Malware Activity

Some malware indicators are observed on this port.

2 of 2 IDS rules for TCP port 9581 involve malware activity.

Families observed (top 1): Win32_Recslurp_D (2).

Data Sources

This information is compiled from: Emerging Threats Open Ruleset (BSD 2-Clause / GPLv2 per SID range).