shadow1ng/fscan · error

close

Error message

close

What it means

Synthetic error created inside the RDP 'close' event handler: the PDU layer reported the session closed (server dropped the connection) without a preceding 'success' or explicit 'error' event, so a generic error is fabricated to signal the connection ended prematurely.

Source

Thrown at libs/grdp/login/screen.go:237

		info["reconn"] = protocol
		g.pdu.Emit("close")
		exitFlag <- true
	})

	err = g.x224.Connect()
	if err != nil {
		info["err"] = err.Error()
		return
	}
	glog.Info("wait connect ok")

	g.pdu.On("error", func(e error) {
		err = e
		glog.Error("error", e)
		g.pdu.Emit("done")
	})
	g.pdu.On("close", func() {
		err = errors.New("close")
		glog.Info("on close")
		g.pdu.Emit("done")
	})
	g.pdu.On("success", func() {
		glog.Debugf("===============login success %s===============", ip)
		err = nil
		g.pdu.Emit("done")
	})
	g.pdu.On("ready", func() {
		err = nil
		glog.Debug("on ready")
	})
	g.pdu.On("bitmap", func(rectangles []pdu.BitmapData) {
	})
	g.pdu.On("done", func() {
		glog.Debug("done signal triggered")
		exitFlag <- true
	})

View on GitHub (pinned to 95cc12e753)

Solutions

1. Retry the RDP connection once; transient closes are common
2. Check network reachability and whether the server limits concurrent sessions
3. Distinguish this from real errors by treating a bare close as 'incomplete', not failure with credentials

When it happens

Trigger: Thrown at libs/grdp/login/screen.go:237 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/7de1b683503b143d. Report an issue: GitHub.