Commonly Used Port
Adversaries may communicate over a commonly used port to bypass firewalls or network detection systems and to blend in with normal network activity, to avoid more detailed inspection. They may use the protocol associated with the port, or a completely different protocol. They may use commonly open ports, such as the examples provided below.
Senses
Sense 1
Adversaries may communicate over a commonly used port to bypass firewalls or network detection systems and to blend in with normal network activity, to avoid more detailed inspection. They may use the protocol associated with the port, or a completely different protocol. They may use commonly open ports, such as the examples provided below.
- TCP:80 (HTTP)
- TCP:443 (HTTPS)
- TCP/UDP:53 (DNS)
- TCP:1024-4999 (OPC on XP/Win2k3)
- TCP:49152-65535 (OPC on Vista and later)
- TCP:23 (TELNET)
- UDP:161 (SNMP)
- TCP:502 (MODBUS)
- TCP:102 (S7comm/ISO-TSAP)
- TCP:20000 (DNP3)
- TCP:44818 (Ethernet/IP)
References
- MITRE ATT&CK (ICS, CTI STIX Data)Jan 06, 2026MITRE ATT&CK CTI (STIX bundle)https://raw.githubusercontent.com/mitre-attack/attack-stix-data/master/ics-attack/ics-attack.jsonSee repository LICENSE.txt for ATT&CK terms: non-exclusive royalty-free license; reproduce MITRE copyright + license in copies. Verify requirements before publishing quoted text.Source: MITRE ATT&CK (attack-stix-data).