Insecure ports -CompTIA Security +
Hola!
I think is cool to learn ports for efficiency i leave here the insecure ports as a personal wiki, references are from the book of Ian Neil on CompTIA plus editing on mark down by AI. Did a missed one? Discuss this post here Bluesky
| Protocol | Port(s) | Main Use | Risks / Insecurity | Secure Alternative |
|---|---|---|---|---|
| Telnet | TCP 23 | Remote access and command execution | Plain text transmission, password theft | SSH |
| FTP | TCP 21 | File transfer | Insecure, data and credentials in plain text | SFTP |
| SMTP | TCP 25 | Email delivery between servers | Unencrypted | SMTPS |
| DNS | UDP/TCP 53 | Name resolution, queries, and zone transfers | Vulnerable without protection | DNSSEC |
| DHCP | UDP 67/68 | Automatic IP address assignment | Can be exploited without secure authentication | - |
| TFTP | UDP 69 | Simple, unauthenticated file transfer | No authentication or encryption | - |
| HTTP | TCP 80 | Web browsing | Unencrypted, vulnerable to interception | HTTPS |
| POP3 | TCP 110 | Email retrieval (no server copy retained) | Unencrypted | POP3S |
| NTP | UDP 123 | Network time synchronization | Can be exploited for DDoS attacks | - |
| NETBIOS | TCP/UDP 137-139 | Name resolution, legacy file and print services | Legacy services, unnecessary exposure | - |
| IMAP4 | TCP 143 | Email access | Unencrypted | IMAPS |
| SNMP v1/v2 | UDP 161 | Network device monitoring and reporting | Uses plain-text "community strings" | SNMPv3 |
| LDAP | TCP 389 | Directory access (e.g., Active Directory) | Vulnerable without encryption | LDAPS |
| Other Risks / Insecure Elements | Description | Recommendation |
|---|---|---|
| Unsecured networks | Includes open Wi-Fi, unprotected wired networks, and weak Bluetooth connections | Use WPA2/3 encryption, secure Bluetooth pairing |
| Open service ports | Expose services that attackers can scan and exploit | Close unnecessary ports |
| Default credentials | Manufacturer-set credentials that can be exploited by attackers | Change default passwords |
| Misconfigurations | Poor system settings (open ports, default settings unchanged) | Regularly audit and review configurations |
