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Port 593HTTP RPC Endpoint Mapper

Port 593 is primarily used for Remote Procedure Call (RPC) communications over HTTP, facilitating DCOM (Distributed Component Object Model) services within Microsoft ecosystems. It enables client-server communication, component activation, and method invocation, typically in distributed enterprise applications and Exchange servers. Since it multiplexes RPC traffic over HTTP, it also helps traverse firewall restrictions while maintaining interoperability between networked services..

inNetwork ServicesSystem
transport
tcp · udp

2 transports registered

in transit
cleartext

payload readable on path

assignment
official

registered with iana

risk
4/10

caution

lookups
26,047

rank 63 of 993 · top 6%

Technical Details

what runs on :593

Port 593, designated for HTTP RPC Endpoint Mapper, facilitates the transmission of Remote Procedure Call requests over the HTTP protocol. This capability expands traditional RPC functionality, allowing remote components and applications to communicate seamlessly across diverse network environments. HTTP encapsulation makes RPC traffic more firewall-friendly, as many network boundaries permit HTTP where direct RPC might be restricted.

In a typical Microsoft environment, this port is instrumental in enabling DCOM services. It supports the activation and invocation of distributed software components, essential for enterprise applications including Microsoft Exchange Server. Through the RPC Endpoint Mapper function, it assists client applications to locate network services by resolving endpoint addresses dynamically, without needing to hard-code port numbers.

The implementation leverages the standard HTTP protocol stack, making it compatible with existing web infrastructure. This means RPC over HTTP can traverse proxies and NAT devices more easily than native RPC, increasing reachability for distributed components. However, it requires careful configuration to ensure that multiplexed services are functioning correctly and securely.

Security Information

exposure of :593

risk score

4/ 10caution

worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.

network services averages 3.9 across 604 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 · udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

Common vulnerabilities associated with port 593 include:

  • Exposure to unauthorized DCOM service invocations, which could allow remote code execution if endpoints are not properly secured.
  • Susceptibility to man-in-the-middle attacks when RPC traffic is unencrypted, enabling interception or manipulation of communications.
  • Exploitation through vulnerabilities in Microsoft RPC services, which have historically been targeted by malware such as Blaster Worm or various privilege escalation exploits.

Typical mitigations involve:

  • Restricting inbound access to port 593 only from trusted subnets or authenticated clients.
  • Implementing network segmentation and rigorous firewall rules to limit RPC traffic exposure.
  • Enabling encryption for RPC over HTTP through SSL/TLS to prevent eavesdropping.
  • Regularly patching Microsoft systems to address RPC-related vulnerabilities.
  • Utilizing endpoint monitoring and intrusion detection to flag anomalous RPC activity.

Related Ports

all 604 in network services →

the 8 most looked-up other ports in network services — 604 ports carry that label.

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:3128Tatsoft Default HTTP Proxycaution

risk mix of the 8 listed

  • caution100%

0 of 8 encrypted