Port 2527: Unassigned — A Gap in the Map

What Range This Port Belongs To

Port 2527 falls in the registered ports range (1024–49151). This range sits between the well-known ports (0–1023), which require root privileges and are assigned to major protocols, and the ephemeral ports (49152–65535), which operating systems hand out temporarily for outgoing connections.

Registered ports are supposed to be claimed by applications and protocols through IANA. Developers register a port so their software has a predictable, known home — a published address others can find. Port 2527 has no such registration. IANA's official registry lists it as unassigned.¹

Third-party port databases mention an "IQ Server" associated with 2527, but there is no traceable RFC, vendor documentation, or specification behind that name. Treat it as a ghost entry.

Known Unofficial Uses

Port 2527 appears in security research contexts, not for any legitimate application.

Zvrop — A piece of malware attributed to "Bekkoame" has been documented using port 2527 for command-and-control communication.² The pattern is familiar: malware authors scan for unmonitored registered ports, pick ones without obvious owners, and use them because firewall rules tend to focus on well-known ports and common application ports.

Trojan.MulDrop.2527 — Dr. Web's malware database documents a dropper variant catalogued by this port number, suggesting it appeared in samples communicating on 2527.³

Neither of these makes port 2527 inherently dangerous — a port number is just a number. But an open port 2527 with no explanation for what's listening is worth investigating.

How to Check What's Listening

If port 2527 appears open on a system, find the process behind it:

Linux/macOS:

sudo ss -tlnp | grep 2527
# or
sudo lsof -i :2527

Windows:

netstat -aon | findstr 2527

The output will include a process ID (PID). Cross-reference that against your running processes (tasklist on Windows, ps aux on Linux/macOS) to identify the owning application.

If nothing recognizable owns it, run a malware scan. An unexplained open port in the registered range is not normal.

Why Unassigned Ports Matter

The port numbering system works on trust. Well-known ports (80, 443, 22) are watched, logged, and understood. Registered ports have named owners. But unassigned registered ports exist in a gray zone — not random enough to be dismissed as ephemeral traffic, not named enough to be monitored by default.

This makes them attractive to software that prefers not to be noticed. The absence of a registered service on 2527 is not a feature of the port. It's just a gap — and gaps invite squatters.