508
Summary
- // typical exposure
- Anomalous (rarely legitimately open) — Port 508 has no documented protocol, no confirmed application mapped to it, and an open-frequency of essentially zero, so an open instance is anomalous rather than a normal service and warrants investigation.
- // analyst note
- An open port 508/tcp has no confirmed legitimate service behind it — investigate rather than assume benign.
- // if you see it open
- No CVE is recorded for port 508 as of an August 2026 search. SANS Internet Storm Center shows sparse, low-volume scanning from a handful of source IPs and a 'green' (low) threat level as of an August 2026 check. No malware or trojan association was found. With no documented protocol and near-zero observed open-frequency, an open 508/tcp should be treated as anomalous and investigated rather than assumed to be routine service traffic.
About port 508/tcp.
Port 508/tcp carries the IANA-registered service name "xvttp," but IANA supplies no protocol description, no RFC, and no reference document behind that name — there is nothing public confirming what actually runs on the port. Because the underlying protocol can't be verified, it should not be assumed to belong on the public internet, and any host answering on it deserves closer inspection rather than trust.
The IANA Service Name and Transport Protocol Port Number Registry lists "xvttp" dual-registered on both 508/tcp and 508/udp, with both rows crediting assignee Keith J. Alphonso and leaving the Reference column blank. No RFC or vendor specification for "xvttp" is publicly discoverable, and the description field simply repeats the service name.
A search for "xvttp" surfaces a U.S. Navy NRL "XVTnet Professional Administrator's Guide" tied to the ATCF tropical-cyclone forecasting tool suite, which raises a superficial resemblance to XVT Software's XVTnet product line. That document itself never mentions port 508 or the string "xvttp," so the connection is unconfirmed and should be treated as speculative only, not as an identified application.
nmap-services open-frequency data records 508/tcp at exactly 0 — a sampled, not-observed-open reading rather than a gap — while 508/udp sits at roughly 0.000461. Both figures point to a port that is essentially never seen open in the wild, consistent with the absence of any documented service behind the registration.
- Exposure
- No confirmed legitimate application maps to 508/tcp; treat an open instance as anomalous and worth investigating rather than as routine service traffic.
- Scanning activity
- SANS Internet Storm Center shows sparse, low-volume scan counts from a handful of source IPs and rates the port's threat level "green" (low) as of an August 2026 check (https://isc.sans.edu/port.html?port=508).
- Notable CVE
- No CVE entry for port 508 is recorded in the NVD or on the SANS ISC port page as of an August 2026 search.
- Malware
- No malware or trojan association was found for this port as of an August 2026 search.
- IANA assignment
xvttp— description field repeats the service name; Reference column blank; assignee Keith_J_Alphonso; dual-registered 508/tcp + 508/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry xvttp 508/tcp- Range class
- well-known (0–1023) [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry xvttp 508/tcp
- Prevalence
- nmap-services open-frequency 508/tcp = 0 (sampled, not observed open); 508/udp ≈ 0.000461 [Confirmed] — this site's own tooling
- Related ports
- 508/udp (dual registration under the same "xvttp" name)
Primary use
Unknown — IANA supplies no protocol description, RFC, or reference for "xvttp"
Other/unofficial uses
none confirmed; a surface resemblance to XVT Software's XVTnet product line surfaced in search but the source document does not mention port 508 or "xvttp"
Security implications
no CVE recorded as of an August 2026 search; SANS ISC shows sparse, low-volume scanning and a "green" (low) threat level as of an August 2026 check; no confirmed malware/trojan association
Typically seen on
no host or application type confirmed; an open 508/tcp is statistically rare and unexplained
- Analyst note
- An open port 508/tcp has no confirmed legitimate service behind it — investigate rather than assume benign.
About port 508/udp.
Port 508/udp carries xvttp, an IANA-registered service name with no documented protocol specification and no confirmed software implementation; because nothing verifies what actually runs on it, it should be treated as anomalous rather than assumed safe, and any observed traffic merits investigation rather than routine exposure, internal or public.
IANA registers xvttp identically on 508/tcp and 508/udp, assigned to Keith J. Alphonso, with a blank Reference field. The registry's own Description column simply repeats the service name ("xvttp") rather than explaining the protocol, and no RFC or other specification is cited anywhere in the registry.
A possible connection to the U.S. Naval Research Laboratory's XVTnet software (used with the Automated Tropical Cyclone Forecasting System) was investigated because of the similar name, but the fetched XVTnet administrator's guide makes no mention of port 508, UDP, or "xvttp," and no corroborating source was found. This link should be treated as unconfirmed, not fact.
No current software or service has been confirmed to generate traffic on 508/udp, and no CVE or named malware family is documented against it as of an August 2026 search. Generic port-scanner directory sites returned no port-508-specific content on this pass, so neither a positive nor a negative malware verdict is drawn from them.
- Exposure
- Anomalous — a sparsely documented, apparently unused registered port; no confirmed legitimate software should be listening on it.
- Notable CVE
- None recorded in the NVD as of an August 2026 search.
- Malware note
- No named malware family or port-508-specific scanner-flag content was found as of an August 2026 search.
- Best practice
- Treat any observed traffic on this port as worth investigating rather than routine, since no confirmed legitimate use pattern exists to expect here.
- IANA assignment
xvttp— description field repeats the service name; reference (blank — no RFC cited); assignee Keith J. Alphonso; dual-registered 508/tcp + 508/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry xvttp 508/tcp; the IANA Service Name and Transport Protocol Port Number Registry xvttp 508/udp; https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?page=10- Range class
- well-known (0–1023) [Confirmed]
- Prevalence
- nmap-services open-frequency 508/udp ≈ 0.000461 (~0.046%); 508/tcp ≈ 0.000000 (not observed open in scan corpus) [Confirmed] — this site's own tooling (built from nmap-services)
- Related ports
- none identified as a documented pair or cluster for xvttp
Primary use
no documented protocol specification found beyond the bare IANA registration; the registry description column only repeats the service name [Confirmed registration / Unknown protocol] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?page=10
Other/unofficial uses
a possible link to the Naval Research Laboratory's XVTnet software (ATCF tooling) was investigated but not corroborated — the XVTnet admin guide does not mention port 508, UDP, or "xvttp"
Security implications
no CVE or named malware family documented for 508/udp as of an August 2026 search; no software confirmed to generate traffic on this port
Typically seen on
no confirmed deployment pattern; a low-visibility, effectively obscure registered port with no corroborating community sightings [Unknown]
- Analyst note
- xvttp has an IANA registration but no verifiable protocol, software, or deployment history — an open 508/udp is unusual and worth investigating rather than assumed routine.
Service assignments.
| Name | Protocol | Description | Open frequency |
|---|---|---|---|
| xvttp | UDP | — | 0.05% |
| xvttp | TCP | — | 0.00% |
Service assignments from the IANA Service Name and Transport Protocol Port Number Registry, with open-frequency data from nmap-services.