It refers to a web server or website delivering HTTP or HTTPS content through ports other than the standard 80 (HTTP) and 443 (HTTPS). While this may be used for traffic isolation or internal applications, threat actors often utilize non-standard ports to evade detection by scanners, crawlers, and security monitoring tools.
Three questions every analyst asks before acting on this signal.
It refers to a web server or website delivering HTTP or HTTPS content through ports other than the standard 80 (HTTP) and 443 (HTTPS). While this may be used for traffic isolation or internal applications, threat actors often utilize non-standard ports to evade detection by scanners, crawlers, and security monitoring tools.
Some domains intentionally host content on uncommon ports to prevent indexing by search engines or discovery by automated tools. These services are usually accessible only via direct links. This technique is frequently seen in phishing sites, gambling platforms, or malicious infrastructures designed to hide from public visibility.
Legitimate web services rarely use ports like 8081, 8443, 5000, or 1337. Attackers often host phishing kits, malware payloads, or command-and-control (C2) dashboards on such ports to bypass traditional security layers. The use of non-standard ports is therefore a strong indicator of potential malicious intent or stealthy operations.
A realistic shape of the entry the engine appends to the risk_signals array when this signal fires. Evidence keys are subgroup-default; per-signal overrides documented in the API reference.
{
"slug": "unusual_http_port",
"name": "HTTP Service on Non-standard Port",
"group": "http_crawling_history",
"subgroup": "web_behavior_structure",
"direction": "malicious",
"evidence": {
"url_shortener_chain": false,
"auto_refresh_seconds": null,
"direct_ip_link": false,
"browser_interaction_required": true
}
}7 other signals share the same subgroup. They detect related behaviors and often co-fire on the same IOC.
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