Port 81 Details
known port assignments and vulnerabilities
threat/application/port search:
Port(s) |
Protocol |
Service |
Details |
Source |
81 |
udp |
trojans |
W32.Beagle.AR@mm (9.29.2004) - mass mailing worm with backdoor functionality on port 81/tcp & udp. Affects all current Windows versions. |
SG
|
81 |
tcp |
http |
Hyper Text Transfer Protocol (HTTP) - ports used for web traffic. See also TCP ports 80, 8080, 8081.
Some common uses for port 81/tcp include web administration (cobalt cube), web proxy servers, McAfee Framework Service, TigerVPN (servers speed check), etc.
If you're not running web services on this port, keep in mind it is also used by some trojans:
Backdoor.Asylum (05.2000) - remote access trojan, uses ports 81, 2342, 23432 by default.
W32.Beagle.AR@mm (09.29.2004) - port 81.
Stack-based buffer overflow in the RespondeHTTPPendiente function in the HTTP server for SUMUS 0.2.2 allows remote attackers to execute arbitrary code via a large packet sent to TCP port 81.
References: [CVE-2005-1110]
RemoConChubo trojan and Blue Iris also use this port. |
SG
|
81 |
tcp |
|
Torpark - Onion routing (unofficial) |
Wikipedia
|
81 |
tcp |
trojan |
Asylum |
Trojans
|
81 |
tcp,udp |
hosts2-ns |
HOSTS2 Name Server |
SANS
|
81 |
tcp |
RemoConChubo |
[trojan] RemoConChubo |
SANS
|
81 |
tcp,udp |
hosts2-ns |
HOSTS2 Name Server |
Nmap
|
81 |
tcp |
threat |
W32.Beagle |
Bekkoame
|
81 |
tcp |
threat |
Xeory |
Bekkoame
|
81 |
udp |
threat |
W32.Beagle |
Bekkoame
|
81 |
tcp,udp |
|
Unassigned, modified: 2007-09-06 |
IANA
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11 records found
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jump to:

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Related ports: 80 2342 8080 23432
« back to SG Ports
External Resources
SANS Internet Storm Center: port 81
Notes:
Well Known Ports: 0 through 1023.
Registered Ports: 1024 through 49151.
Dynamic/Private : 49152 through 65535.
TCP ports use the Transmission Control Protocol. TCP is the most commonly used protocol
on the Internet and any TCP/IP network. Whereas the IP protocol deals only with packets, TCP enables two hosts
to establish a connection and exchange streams of data. TCP guarantees delivery of data
and that packets will be delivered in the same order in which they were sent.
Guaranteed communication/delivery is the key difference between TCP and UDP.
UDP ports use the Datagram Protocol, a communications protocol for the Internet network,
transport, and session layers. Like TCP (Transmission Control Protocol),
UDP is used with IP (the Internet Protocol) and makes possible the transmission of datagrams
from one computer to applications on another computer, but unlike TCP, UDP is connectionless
and does not guarantee reliable communication; it's up to the application that received
the message to process any errors and verify correct delivery. UDP is often used with time-sensitive
applications, such as audio/video streaming, where dropping some packets is preferable to waiting for delayed data.
When troubleshooting unknown open ports, it is useful to find exactly what services/processes are listening to them.
This can be accomplished in both Windows command prompt and Linux variants using the "netstat -aon" command.
We also recommend runnig multiple anti-virus/anti-malware scans to rule out the possibility of active malicious software.
For more detailed and personalized help please use our forums.
Please use the "Add Comment" button below to provide additional information or comments about port 81.
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