Exposed Services Found on TCP Port 0 in Internet-Wide Scan

• •A scan of TCP port 0 revealed exposed industrial and phone systems.
• •21 Avaya IP Office systems were found leaking call records.
• •The scan identified over 1.1 million IPv4 addresses responding to port 0.

Security researcher acidvegas conducted an internet-wide scan targeting TCP port 0, revealing exposed industrial controls, alarm systems, and business phone systems. The scan identified 1,173,626 IPv4 addresses responding to port 0, with significant findings including 21 Avaya IP Office systems that disclosed call records to any connecting party. Although TCP port 0 is reserved and typically not used for active services, the scan demonstrated that some devices were improperly configured to respond on this port. The findings raise concerns about the security of devices that should not be accessible via this port. The results were detailed in a report published on November 6, 2026, and highlight the potential risks of misconfigured network equipment.