{"record":{"id":"2822d5484cc82081","repo":"projectdiscovery/nuclei","slug":"no-response-data-from-s","errorCode":null,"errorMessage":"no response data from %s","messagePattern":"no response data from (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"pkg/js/libs/kerberos/sendtokdc.go","lineNumber":165,"sourceCode":"\n// sendUDP sends bytes to connection over UDP.\nfunc sendUDP(conn *net.UDPConn, b []byte) ([]byte, error) {\n\tvar r []byte\n\tdefer func() {\n\t\t_ = conn.Close()\n\t}()\n\t_, err := conn.Write(b)\n\tif err != nil {\n\t\treturn r, fmt.Errorf(\"error sending to (%s): %v\", conn.RemoteAddr().String(), err)\n\t}\n\tudpbuf := make([]byte, 4096)\n\tn, _, err := conn.ReadFrom(udpbuf)\n\tr = udpbuf[:n]\n\tif err != nil {\n\t\treturn r, fmt.Errorf(\"sending over UDP failed to %s: %v\", conn.RemoteAddr().String(), err)\n\t}\n\tif len(r) < 1 {\n\t\treturn r, fmt.Errorf(\"no response data from %s\", conn.RemoteAddr().String())\n\t}\n\treturn r, nil\n}\n\n// sendTCP sends bytes to connection over TCP.\nfunc sendTCP(conn *net.TCPConn, b []byte) ([]byte, error) {\n\tdefer func() {\n\t\t_ = conn.Close()\n\t}()\n\tvar r []byte\n\t// RFC 4120 7.2.2 specifies the first 4 bytes indicate the length of the message in big endian order.\n\thb := make([]byte, 4)\n\tbinary.BigEndian.PutUint32(hb, uint32(len(b)))\n\tb = append(hb, b...)\n\n\t_, err := conn.Write(b)\n\tif err != nil {\n\t\treturn r, fmt.Errorf(\"error sending to KDC (%s): %v\", conn.RemoteAddr().String(), err)","sourceCodeStart":147,"sourceCodeEnd":183,"githubUrl":"https://github.com/projectdiscovery/nuclei/blob/265b3a3dec374741614e342f813c10f8b38d2bb7/pkg/js/libs/kerberos/sendtokdc.go#L147-L183","documentation":"sendUDP read a datagram successfully but it contained zero bytes: the KDC (or something impersonating it) replied with an empty payload. The library treats an empty UDP answer as a protocol violation rather than returning empty data to the caller.","triggerScenarios":"A middlebox or honeypot answering with an empty UDP datagram; a KDC closing out a malformed request with a zero-length reply; extremely rare kernel-level truncation.","commonSituations":"Scanning lab targets and honeypots that imitate service sockets; NAT devices mangling small UDP replies.","solutions":["Retry the request once to rule out a one-off mangled datagram","Cross-check with the TCP path: send the same message over TCP and compare","Treat hosts that consistently answer empty as misbehaving and skip further Kerberos probes"],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":null,"typeGuard":null,"tryCatchPattern":"try {\n  const resp = kerberos.SendToKDC(client, msg);\n} catch (e) {\n  // empty UDP datagram from the KDC: retry once, then cross-check over TCP\n}","preventionTips":["Treat consistently empty UDP replies as a misbehaving host","Cross-validate with the TCP transport before trusting a host's Kerberos service"],"tags":["kerberos","udp","protocol"],"backgroundTag":null,"analyzedSha":"265b3a3dec374741614e342f813c10f8b38d2bb7","analyzedAt":"2026-08-15T20:05:51.855Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}