shadow1ng/fscan · error

smbv2_session_send_failed

Error message

smbv2_session_send_failed: %w

What it means

Guard in probeSMBv2: writing the Session Setup request after negotiate failed. Without the session-setup exchange the NTLM challenge/response flow cannot proceed, so no host fingerprint (OS info) is collected.

Solutions

1. Retry the probe
2. Raise the connection deadline
3. Verify the server accepts anonymous session setup requests

When it happens

Trigger: Thrown at plugins/services/smb_protocol.go:325 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of shadow1ng/fscan@95cc12e753 (2026-09-06). Data as JSON: /api/errors/86d7625f42fda4c8. Report an issue: GitHub.

Appendix: source

Thrown at plugins/services/smb_protocol.go:325

	r2, err := readSMBMessage(conn2)
	if err != nil {
		return nil, fmt.Errorf("%s: %w", i18n.GetText("smbv2_negotiate_read_failed"), err)
	}

	// 构建NTLM数据包
	var ntlmData []byte
	if len(r2) > 70 && hex.EncodeToString(r2[70:71]) == "03" {
		flags := []byte{0x15, 0x82, 0x08, 0xa0}
		ntlmData = buildNTLMSSPData(flags)
	} else {
		flags := []byte{0x05, 0x80, 0x08, 0xa0}
		ntlmData = buildNTLMSSPData(flags)
	}

	// 发送Session Setup
	_, err = conn2.Write(smbv2SessionSetupPacket)
	if err != nil {
		return nil, fmt.Errorf("%s: %w", i18n.GetText("smbv2_session_send_failed"), err)
	}

	_, err = readSMBMessage(conn2)
	if err != nil {
		return nil, fmt.Errorf("%s: %w", i18n.GetText("smbv2_session_read_failed"), err)
	}

	// 发送NTLM协商包
	_, err = conn2.Write(ntlmData)
	if err != nil {
		return nil, fmt.Errorf("%s: %w", i18n.GetText("smbv2_ntlm_send_failed"), err)
	}

	ret, err := readSMBMessage(conn2)
	if err != nil {
		return nil, fmt.Errorf("%s: %w", i18n.GetText("smbv2_ntlm_read_failed"), err)
	}

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