375
Summary
- // typical exposure
- Anomalous (rarely legitimately open) — No documented modern software or specification uses this port, nmap-services shows near-zero open frequency, and SANS ISC scanning data shows only routine background noise with no associated CVEs, so any traffic on 375/tcp is most likely scan noise or misconfiguration rather than a legitimate service.
- // analyst note
- an open 375/tcp has no known legitimate explanation — treat as scan noise, misconfiguration, or worth manual investigation.
- // if you see it open
- No CVEs are documented against this port. SANS ISC's port-375 tracker shows only light, routine background internet scanning (a handful of source IPs per day), consistent with generic sweep noise rather than targeted exploitation of a known service. Because no protocol specification is published, the port's actual security properties cannot be assessed, and any responsive host is anomalous.
About port 375/tcp.
Port 375/tcp carries a service IANA registered only as hassle, with no published specification found anywhere; it has essentially no documented modern use, so it should stay internal-only (or simply closed) rather than sit exposed to the public internet.
IANA lists 375/tcp and 375/udp under the service name hassle, description "Hassle," assignee Reinhard Doelz, with a blank Reference field — no RFC or other spec is cited for this assignment. Doelz was affiliated with the Biozentrum, University of Basel, an EMBnet bioinformatics-network node, which is the only lead available on the name's origin, but no primary source documents what protocol actually runs on the port.
Multiple search passes (general web search, DuckDuckGo, Bing, Marginalia, and the nmap-services corpus) turned up no vendor documentation, forum post, or banner reference to any application using 375/tcp. nmap's nmap-services frequency file records the port as essentially never seen open (~0.0 on tcp; ~0.0005 on udp), consistent with no real-world deployment.
SANS Internet Storm Center's port tracker shows only light, routine background scanning on 375 — a handful of source IPs logged per day and no CVEs associated with the port — the profile of generic internet-wide sweep noise rather than exploitation of a known service.
- Exposure
- Anomalous — no documented legitimate use exists, and nmap-services shows it essentially never open; treat any responsive host on 375/tcp as worth investigating rather than expected. [Likely] — https://raw.githubusercontent.com/nmap/nmap/master/nmap-services
- Scanning activity
- SANS ISC logs only low-volume background scan noise on port 375 (a few source IPs per day), with no CVEs tied to the port. [Confirmed] — https://isc.sans.edu/port.html?port=375
- Notable CVE
- none found; no CVE is documented against this port or the
hassleservice. [Unknown] - Protocol risk
- because no specification is published, the actual wire protocol and its security properties (auth, encryption) cannot be assessed. [Unknown]
- IANA assignment
hassle— "Hassle"; reference (blank — no RFC cited in IANA registry); assignee Reinhard Doelz; dual-registered 375/tcp + 375/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry (lines 743-744); https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml- Range class
- well-known (0–1023) [Confirmed]
- Prevalence
- nmap-services open-frequency 375/tcp ≈ 0.000000; 375/udp ≈ 0.000544 (essentially never observed open) [Confirmed] — https://raw.githubusercontent.com/nmap/nmap/master/nmap-services
- Related ports
- none specifically documented for this entry [Unknown]
Primary use
not documented in any accessible primary source; possibly related to Reinhard Doelz's EMBnet/Biozentrum bioinformatics-network affiliation, but unconfirmed
Other/unofficial uses
none found in vendor docs, forums, or scan-banner data [Unknown]
Security implications
no CVEs documented; SANS ISC shows only routine low-volume background scan noise, no targeted-exploitation signature
Typically seen on
no known legitimate deployments documented; a responsive host is anomalous [Unknown]
- Analyst note
- an open 375/tcp has no known legitimate explanation — treat as scan noise, misconfiguration, or worth manual investigation.
About port 375/udp.
Port 375/udp is registered with IANA under the service name "hassle," but no protocol specification, working document, or dominant real-world application has been verified for it, so it should be treated as an unclear/anomalous service rather than assumed safe to expose or ignore.
The IANA registry lists the entry with description "Hassle," assignee and contact Reinhard Doelz, and a blank Reference field — no RFC or specification is cited. The same service name is dual-registered on 375/tcp, assigned to the same contact, which is common for older IANA entries that predate strict single-transport registration.
No independent source in this research pass could confirm what the "hassle" protocol actually does, what software implements it, or how commonly it appears in real traffic. Searches turned up only low-quality, apparently auto-generated port-lookup aggregator pages whose claims (a "client-server architecture," generic cryptography descriptions, and an unattributed historical "trojan" flag on the TCP counterpart) read as templated filler rather than sourced fact, and are not treated as reliable here.
Given the absence of documentation, an analyst encountering traffic on 375/udp has no confirmed legitimate baseline to compare it against. The port's obscurity and total lack of a verifiable protocol description mean any observed traffic merits closer inspection rather than being written off as routine.
- Exposure
- No verified protocol specification or software attribution exists for 375/udp, so there is no documented legitimate use to weigh against exposure — treat any traffic as worth investigating rather than routine. [Unknown]
- Registry status
- Dual-registered on TCP and UDP under the same assignee, with a blank IANA Reference field — no RFC backs the assignment. [Confirmed] — IANA registry
- Unverified aggregator claims
- Some port-lookup aggregator sites mention an unattributed historical "trojan" flag on the TCP side and templated protocol descriptions; these could not be corroborated against a primary source and are not reported as fact. [Unknown]
- IANA assignment
hassle— "Hassle"; reference (blank — no RFC cited in IANA registry); assignee/contact Reinhard Doelz; dual-registered 375/tcp + 375/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry (lines 743-744); IANA Service Name and Transport Protocol Port Number Registry- Range class
- well-known (0–1023) [Confirmed]
- Prevalence
- Unknown — no nmap-services entry or scanning telemetry located for 375/udp in this research pass [Unknown]
- Related ports
- 375/tcp (same "hassle" dual registration, same assignee) [Confirmed]
Primary use
Unknown — no protocol specification, RFC, or documentation was located beyond the bare IANA label "hassle" [Unknown]
Other/unofficial uses
None verified; aggregator-site claims (client-server architecture, cryptography description) are unsourced/templated and are not corroborated [Unknown]
Security implications
No documented protocol or malware association was found; an unattributed aggregator claim of a historical "trojan" flag on the TCP counterpart could not be corroborated against a primary source [Unknown]
Typically seen on
Unknown — no credible sightings of software using this port were found [Unknown]
- Analyst note
- Absence of any protocol documentation plus low-quality, unsourced aggregator noise means an open 375/udp cannot be attributed to a specific application with confidence — investigate rather than assume.
Service assignments.
| Name | Protocol | Description | Open frequency |
|---|---|---|---|
| hassle | UDP | — | 0.05% |
| hassle | TCP | — | 0.00% |
Service assignments from the IANA Service Name and Transport Protocol Port Number Registry, with open-frequency data from nmap-services.