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Port Exposure

The Port Exposure factor measures how many ports are open and how risky the exposed services are. Wide port ranges receive high scores regardless of service type, while single-port rules are scored based on the known risk level of that service.

Default max contribution: 25 points.

Scoring table

Port ranges

Port ConfigurationPointsNotes
All ports (1-65535) or "any"25 (max)Full exposure
> 1,000 ports22Large range
101 - 1,000 ports18Moderate range
11 - 100 ports12Small range
2 - 10 ports8 + risk bumpSee risk bump below

Single ports

Service Risk LevelPointsExamples
CRITICAL18Telnet (23), Redis (6379)
HIGH15FTP (21), RDP (3389), SMB (445)
MEDIUM10SSH (22), DNS (53)
LOW0HTTPS (443)
Unknown3No known service match

ICMP

When the protocol is ICMP, no port applies. The Port Exposure factor is omitted entirely from the score calculation - the remaining three factors are used and the score still scales to 100.

Risk bump for small ranges (2 - 10 ports)

When a flow specifies 2 to 10 ports, the base score of 8 is increased by a risk bump based on the highest-risk port in the range:

Highest Port RiskBump
CRITICAL+5 (total 13)
HIGH+4 (total 12)
MEDIUM+2 (total 10)
LOW or unknown+0 (total 8)

For example, a rule allowing ports 22,443 (SSH is MEDIUM, HTTPS is LOW) gets 8 + 2 = 10 points because SSH is the highest-risk port in the set.