owasp-amass/amass · error

invalid port range format

Error message

invalid port range format

What it means

convertPortRangeToSlice splits a range string on '-' and requires exactly two parts (start and end). This error is returned for strings that do not match the 'N-M' format, such as missing dashes or extra dashes.

Source

Thrown at config/scope.go:135

				if err != nil {
					return fmt.Errorf("invalid port string: %v", err)
				}
				s.Ports = append(s.Ports, portNum)
			}
		default:
			return fmt.Errorf("unsupported port type: %T", p)
		}
	}

	return nil
}

func convertPortRangeToSlice(portRange string) ([]int, error) {
	var ports []int

	parts := strings.Split(portRange, "-")
	if len(parts) != 2 {
		return nil, fmt.Errorf("invalid port range format")
	}

	start, err := strconv.Atoi(parts[0])
	if err != nil {
		return nil, fmt.Errorf("invalid start port: %v", err)
	}

	end, err := strconv.Atoi(parts[1])
	if err != nil {
		return nil, fmt.Errorf("invalid end port: %v", err)
	}

	for i := start; i <= end; i++ {
		ports = append(ports, i)
	}

	return ports, nil
}

View on GitHub (pinned to 79299dce87)

Solutions

1. Write the range as exactly start-end with one hyphen, e.g. '80-90'
2. Remove extra hyphens or chained ranges; use separate entries for non-contiguous ports
3. Ensure neither side of the hyphen is empty

Example fix

// before
ports: ["80-90-100"]
// after
ports: ["80-90", "100"]

matched, _ := regexp.MatchString(`^\d+-\d+$`, s); if !matched { return fmt.Errorf("port range must be N-M: %q", s) }

func isPortRange(s string) bool { m, _ := regexp.MatchString(`^\d+-\d+$`, s); return m }

When it happens

Trigger: A port entry like '80-90-100', '80--90', '80-' or '-90' is passed to parsePorts and routed to convertPortRangeToSlice; strings.Split yields a part count other than 2.

Common situations: Chained ranges in config (80-85-90), trailing/leading hyphens from manual editing, negative-looking numbers, or typos like '8O-90' with two delimiters.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

• invalid port string: %v
• unsupported port type: %T
• invalid start port: %v
• invalid end port: %v
• no resolver keys were found in the resolvers section

AI-assisted analysis of owasp-amass/amass@79299dce87 (2026-09-06). Data as JSON: /api/errors/a7800fb638ebdb04. Report an issue: GitHub.