shadow1ng/fscan · error

smbv2_session_send_failed: %w

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.

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)
	}

View on GitHub (pinned to 95cc12e753)

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.