Port 500 Details
known port assignments and vulnerabilities
6 records found
||IPSec (VPN tunneling) uses the following ports:
50 - Encapsulation Header (ESP)
51 - Authentication Header (AH)
500/udp - Internet Key Exchange (IKE)
4500/udp - NAT traversal
500/tcp - sometimes used for IKE over TCP
port 1701 (L2TP)
port 1723 (PPTP)
Some Apple applications use this port as well: Mac OS X Server VPN service, Back to My Mac (MobileMe, Mac OS X v10.5 or later).
isakmp_sub_print in tcpdump 3.6 through 3.7.1 allows remote attackers to cause a denial of service (CPU consumption) via a certain malformed ISAKMP packet to UDP port 500, which causes tcpdump to enter an infinite loop.
References: [CVE-2003-0108] [BID-6974]
Microsoft Windows XP allows remote attackers to cause a denial of service (CPU consumption) by flooding UDP port 500 (ISAKMP).
Snapgear Lite+ firewall 1.5.3 allows remote attackers to cause a denial of service (IPSEC crash) via a zero length packet to UDP port 500.
References: [CVE-2002-0603] [BID-4659]
Cisco Wireless LAN Controller is vulnerable to a denial of service, caused by an error when handling Internet Key Exchange (IKE) messages. By sending a specially-crafted IKE packet to UDP Port 500, a remote attacker could exploit this vulnerability to cause the device to crash and reload.
References: [CVE-2010-0574] [XFDB-61666] [BID-43059]
A vulnerability in MikroTik Version 6.38.5 could allow an unauthenticated remote attacker to exhaust all available CPU via a flood of UDP packets on port 500 (used for L2TP over IPsec), preventing the affected router from accepting new connections; all devices will be disconnected from the router and all logs removed automatically.
References: [CVE-2017-8338], [XFDB-126179]
Vodafone Sure Signal also uses this port
||Internet Security Association and Key Management Protocol (ISAKMP) (official)
||VPN Key Exchange
Related ports: 50 123 259 264 1701 1723 4500
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SANS Internet Storm Center: port 500
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.
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