Port 5190ICQ & AIM
Port 5190 is widely recognized as the default communication port for ICQ and AOL Instant Messenger (AIM), which were among the earliest widely adopted instant messaging platforms. These services enabled real-time communication over the Internet using proprietary protocols that primarily operated over TCP. This port facilitated user sign-in, status updates, message exchanges, and file transfers between IM clients..
- transport
- tcp
- in transit
- cleartext
- assignment
- official
- risk
- 4/10
- lookups
- 8,490
single transport
payload readable on path
registered with iana
caution
rank 592 of 993 · top 60%
Technical Details
what runs on :5190Port 5190 was extensively used by the proprietary protocols of ICQ and AOL Instant Messenger, known as OSCAR (Open System for Communication in Realtime). When a user launched an IM client, it initiated a TCP connection via this port to the service provider’s centralized servers to establish presence and facilitate real-time message exchanges. The communication over this port enabled user sign-ons, contact list management, presence updates, and transmission of chat messages.
Beyond basic messaging, this port also handled ancillary functions, including file transfers, offline messaging, and chat invitations. Since the protocol was closed, third-party software had to engage in protocol reverse-engineering to achieve interoperability. Over time, the use cases expanded to include features like chat rooms and multimedia integration over the same port.
Despite shifts to newer messaging paradigms and platforms, port 5190 serves as a notable historical reference for instant messaging technology. It exemplified the early architecture of centralized messaging platforms relying heavily on a single TCP port for all primary communication functions.
Security Information
exposure of :5190risk score
4/ 10caution
worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.
voice and chat averages 3.9 across 120 ports — this one sits 0.1 above.
in transit
cleartext
credentials and payloads are readable by anyone on path
assignment
official
registered with iana for this service — scanners fingerprint it by number
reachable over
tcp
every listening transport is another surface to filter at the edge
security overview
Common Vulnerabilities:
- Lack of encryption led to susceptibility to packet sniffing, enabling attackers to intercept login credentials or messages.
- Vulnerabilities in the client or protocol implementations exposed users to buffer overflows and code execution exploits.
- Susceptibility to social engineering and spoofing attacks via IM spam and malware dissemination.
Common Mitigations:
- Enforce network segmentation and limit access to port 5190 to trusted hosts only.
- Use firewall rules to restrict unwanted inbound/outbound traffic on this port.
- Transition to messaging platforms supporting strong encryption (such as TLS/SSL), and disable legacy protocols where possible.
- Deploy intrusion detection/prevention systems to monitor and block suspicious IM activities.
- Keep client software patched and educate users about social engineering risks.
Related Ports
the 8 most looked-up other ports in voice and chat — 120 ports carry that label.
| port | service | risk | |||
|---|---|---|---|---|---|
| :9090 | Openfire Admin Console | TCP | Web Services | caution | 34.2k |
| :1513 | Garena Gaming | TCPUDP | Gaming | caution | 33.1k |
| :9091 | Openfire Admin Console (SSL) | TCPtls | Web Services | caution | 28.3k |
| :2031 | Mobrien Chat | TCPUDP | Web Services | caution | 27.7k |
| :1720 | H.323 Signaling | TCP | Network Services | caution | 26.5k |
| :6005 | Camfrog Chat | TCP | Voice and Chat | caution | 25.2k |
| :3001 | Miralix Phone Monitor | TCP | Network Services | caution | 21.7k |
| :9009 | Pichat Server | TCPUDP | Network Services | caution | 19.7k |
risk mix of the 8 listed
- caution100%
1 of 8 encrypted