Port 110: POP3
Analyze default service protocols, historical security vulnerabilities, hardening methods, and firewall rules for port 110.
1. Port Purpose & Usage
Post Office Protocol version 3 (POP3) is a standard mail protocol used by email clients to retrieve messages from a mail server. It typically deletes messages from the server once they are downloaded.
Common Service Implementations
A secure, high-performance IMAP and POP3 server for Linux systems.
A lightweight, fast POP3 server daemon.
2. Security Risks & Vulnerability Profiles
Standard POP3 on port 110 transmits email passwords and message contents in clear text. Passive sniffing on local networks or intermediate routers can expose mailbox access credentials.
Historical CVE References
Dovecot POP3 Authentication Bypass. Under specific database configurations, authentication parameters could be bypassed, letting malicious actors sign in to user mailboxes.
3. Hardening & Mitigation Checklist
4. Firewall Command Examples
Use the following system configurations to restrict open port exposure on Linux hosts:
Further Analysis
Email Infrastructure Ports
Ports often operate in clusters. When analyzing a service on Port 110, security engineers typically check the status of these related ports.