projectdiscovery/nuclei · error

invalid signature type:

Error message

invalid signature type: 

What it means

The `signature:` field on an HTTP request is mapped by toSignatureType (trim + case-normalize) against the signatureTypeMappings table. Currently the only supported value is "AWS" (AWS Signature Version 4 signing via the signer package); any other string fails template compilation with this error.

Source

Thrown at pkg/protocols/http/signature.go:42

	AWSSignature: "AWS",
}

func GetSupportedSignaturesTypes() []SignatureType {
	var result []SignatureType
	for index := SignatureType(1); index < signatureLimit; index++ {
		result = append(result, index)
	}
	return result
}

func toSignatureType(valueToMap string) (SignatureType, error) {
	normalizedValue := normalizeValue(valueToMap)
	for key, currentValue := range signatureTypeMappings {
		if normalizedValue == currentValue {
			return key, nil
		}
	}
	return -1, errors.New("invalid signature type: " + valueToMap)
}

func (t SignatureType) String() string {
	return signatureTypeMappings[t]
}

// SignatureTypeHolder is used to hold internal type of the signature
type SignatureTypeHolder struct {
	Value SignatureType
}

func (holder SignatureTypeHolder) JSONSchema() *jsonschema.Schema {
	gotType := &jsonschema.Schema{
		Type:        "string",
		Title:       "type of the signature",
		Description: "Type of the signature",
	}
	for _, types := range GetSupportedSignaturesTypes() {

View on GitHub (pinned to 265b3a3dec)

Solutions

1. Use `signature: AWS` for AWS Signature V4 signing, or remove the signature field entirely
2. For other auth schemes use the dedicated auth fields (bearer-token, basic auth) or headers
3. Validate the template with nuclei -validate

Example fix

# before
http:
  - raw:
      - |
        GET / HTTP/1.1
    signature: AWS4

# after
http:
  - raw:
      - |
        GET / HTTP/1.1
    signature: AWS

func isValidSignatureType(v string) bool {
    return strings.ToUpper(strings.TrimSpace(v)) == "AWS" // only supported value today
}

When it happens

Trigger: Setting `signature:` to an unsupported scheme such as `signature: HMAC`, `signature: BASIC`, or a near-miss like `signature: AWS4` / `signature: SigV4`. Only `signature: AWS` (any casing) is accepted.

Common situations: Assuming multiple auth-signing schemes exist; copying doc examples for other tools; guessing the identifier for SigV4.

Related errors

• Invalid HTTP method verb: %s
• probe concurrency must be at least 1
• response read size must be non-negative
• empty filename
• Invalid action type: %s

AI-assisted analysis of projectdiscovery/nuclei@265b3a3dec (2026-08-15). Data as JSON: /api/errors/e1e15edfd2634552. Report an issue: GitHub.