Port 1332 sits in the registered range, officially assigned to a protocol called "PCIA RXP-B."1 There's just one problem: no one knows what PCIA RXP-B actually does. No specification exists. No software openly uses it. The registration exists, but the protocol is a ghost.
The Registered Ports Range
Port 1332 falls in the registered ports range (1024-49151). This is the middle tier of the port system—above the well-known ports (0-1023) that require administrator privileges, below the dynamic/ephemeral ports (49152-65535) that applications grab temporarily.
Registered ports are assigned by IANA to specific services, but unlike well-known ports, they don't have the same weight of history or universal adoption. Many registered ports represent protocols that were proposed, registered, and then... nothing. The Internet moved on.
Port 1332 appears to be one of these.
What Is PCIA RXP-B?
According to IANA's registry, port 1332 is assigned to "PCIA RXP-B" for both TCP and UDP.1 But search for documentation, RFCs, or any technical specification—you won't find it. The acronym suggests something to do with "RXP" (possibly a receive protocol?) and designation "B" (perhaps a variant?), but that's speculation.
The protocol was registered. Someone claimed this port number. But whatever PCIA RXP-B was supposed to be, it never materialized into something the Internet actually uses.
This happens more often than you'd think. The port registry is full of these ghosts—protocols registered with good intentions that never gained traction, proprietary systems that were abandoned, research projects that ended.
The Uninvited Guest
Here's where port 1332's story gets darker.
If you scan your network and find port 1332 listening, the most likely explanation isn't PCIA RXP-B. It's Backdoor.Win32.Beastdoor—a malware family that sets up shop on port 1332.2
The Beastdoor backdoor listens on TCP port 1332, waiting for commands from a remote attacker. Once connected, it can:
- Capture screenshots and webcam video
- Log keystrokes and steal credentials
- Download and execute arbitrary files
- Open/close the CD-ROM drive (a classic backdoor taunt)
- Send infection details to the attacker via email on port 252
The malware drops a file named svchost.exe in the Windows directory—mimicking the legitimate Windows service host process—and allows unauthenticated remote command execution.2
This is the irony of empty ports. IANA maintains careful registrations for protocols that never materialized. Meanwhile, malware quietly moves into the vacant space. The registry says "PCIA RXP-B." The reality says "backdoor."
How to Check What's Listening
On Windows, use netstat or PowerShell to see if anything is listening on port 1332:
Or with PowerShell:
On Linux or macOS, use lsof or ss:
If you find something listening on port 1332 and you're not running a service you explicitly configured, investigate immediately. Run antivirus and antimalware scans. Check the process ID and executable path. Don't assume it's benign.
Why Unassigned and Obscure Ports Matter
The port registry isn't just a bureaucratic list—it's a map of the Internet's nervous system. Well-known ports like 80 (HTTP) and 443 (HTTPS) are constantly monitored, heavily firewalled, and widely understood. Everyone knows what should be on those ports.
But registered ports in the middle range? They're the Internet's back alleys. Less scrutiny. Less awareness. Perfectly ordinary for a firewall to allow registered port traffic without question.
This makes them attractive to malware. A backdoor on port 80 would be noticed immediately. A backdoor on port 1332—registered to a protocol no one's heard of—can operate undetected for longer.
The lesson: An officially registered port doesn't mean legitimate traffic. The registry tells you what the port was assigned for, not what's actually using it. Always verify.
The Empty Rooms
Port 1332 is a reminder that the Internet contains multitudes of these empty rooms—protocols proposed but never adopted, services registered but never launched, good intentions that became ghosts.
IANA maintains the registry with care. Someone, at some point, requested port 1332 for PCIA RXP-B. They had plans. They had a protocol. And then, for reasons unknown, it faded away.
What remains is the registration. A name without a body. And in the vacuum, something else moved in.
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