Tighten WebCRT command audit: reject device errors and stdout replay.

Only audit interactive commands from frontend audit_line with a CLI prompt prefix; skip prompt-sync Enter and device error echoes; join wrapped xterm rows for long commands.

Co-authored-by: Cursor <cursoragent@cursor.com>

netx_api/webcrt_channel.py

@@ -539,14 +539,49 @@ def _is_prompt_command_line(line: str) -> bool:
     )
 
 
+def _has_cli_prompt_prefix(line: str) -> bool:
+    s = normalize_audit_line(line)
+    return bool(
+        re.match(
+            r"^(?:"
+            r"[\w.-]+(?:\([^)]+\))*[#>]"
+            r"|>[\w.-]+"
+            r"|<[^>]+>"
+            r"|\[[^\]]+\]"
+            r")",
+            s,
+            flags=re.I,
+        )
+    )
+
+
+def _is_device_output_line(line: str) -> bool:
+    """Device error/warning echo — never an operator-typed command."""
+    s = normalize_audit_line(line).strip()
+    if not s:
+        return False
+    low = s.lower()
+    if low.startswith("%error") or low.startswith("%warning"):
+        return True
+    if "invalid input detected" in low:
+        return True
+    if re.match(r"^\^+\s*$", s):
+        return True
+    if re.match(r"^enter configuration commands", low):
+        return True
+    return False
+
+
 def is_auditable_command_line(line: str) -> bool:
-    """False for empty Enter (prompt only, no command text)."""
+    """False for empty Enter, device output, or lines without a CLI prompt prefix."""
     s = normalize_audit_line(line)
     if not s.strip():
         return False
     if _is_prompt_only_line(s):
         return False
-    return True
+    if _is_device_output_line(s):
+        return False
+    return _has_cli_prompt_prefix(s)
 
 
 def _is_prompt_only_line(line: str) -> bool:

netx_api/webcrt_router.py

@@ -801,7 +801,10 @@ async def websocket_session(websocket: WebSocket, session_id: str) -> None:
     if sess.needs_live_prompt:
         sess.needs_live_prompt = False
         try:
-            await asyncio.get_running_loop().run_in_executor(webcrt_io_executor(), sess.write_stdin, "\r")
+            await asyncio.get_running_loop().run_in_executor(
+                webcrt_io_executor(),
+                lambda: sess.write_stdin("\r", audit_source="prompt_sync"),
+            )
         except Exception:
             _log.debug("webcrt live prompt sync failed session=%s", session_id, exc_info=True)
     try:

netx_api/webcrt_session_model.py

@@ -385,28 +385,26 @@ class WebcrtSession:
             if redacted and (buf_lines or audit_line):
                 self._password_mode = False
             if "\r" in text or "\n" in text:
-                from .webcrt_channel import (
+                from .webcrt_channel import is_auditable_command_line, normalize_audit_line
-                    extract_last_prompt_command,
-                    is_auditable_command_line,
-                    normalize_audit_line,
-                )
 
-                # Ground truth: xterm visible row at Enter (frontend). PTY stdout/stdin
+                src = str(source or "stdin")
-                # still carry intermediate backspaces / tab redraws — do not prefer those.
                 cmd: str | None = None
-                if audit_line and str(audit_line).strip():
+                if redacted and (audit_line or buf_lines):
+                    lines = ["***"]
+                elif src == "prompt_sync":
+                    lines = []
+                elif audit_line and str(audit_line).strip():
                     candidate = normalize_audit_line(audit_line)
                     if is_auditable_command_line(candidate):
                         cmd = candidate
-                if not cmd:
+                    lines = [cmd] if cmd else []
-                    raw = extract_last_prompt_command(self._stdout_tail)
+                elif src == "post_login":
-                    if raw and is_auditable_command_line(raw):
+                    if buf_lines and str(buf_lines[-1]).strip():
-                        cmd = raw
+                        cmd = str(buf_lines[-1]).strip()
-                    elif buf_lines and str(buf_lines[-1]).strip():
+                    lines = [cmd] if cmd else []
-                        last = str(buf_lines[-1]).strip()
+                else:
-                        if is_auditable_command_line(last):
+                    # Interactive WebCRT: only trust frontend audit_line at Enter.
-                            cmd = last
+                    lines = []
-                lines = [cmd] if cmd else []
                 self._last_prompt_line = ""
             else:
                 lines = []

tests/test_webcrt_audit.py

@@ -14,6 +14,7 @@ from netx_api.webcrt_channel import (
     extract_last_prompt_command,
     finalize_audit_line,
     is_auditable_command_line,
+    _is_device_output_line,
     _is_prompt_only_line,
 )
 from netx_api.webcrt_session_model import WebcrtSession
@@ -133,6 +134,14 @@ class AuditableCommandLineTests(unittest.TestCase):
         self.assertFalse(_is_prompt_only_line(line))
         self.assertTrue(is_auditable_command_line(line))
 
+    def test_device_error_not_auditable(self) -> None:
+        line = "%Error 140303: Invalid input detected at '^' marker."
+        self.assertTrue(_is_device_output_line(line))
+        self.assertFalse(is_auditable_command_line(line))
+
+    def test_plain_stdin_without_prompt_not_auditable(self) -> None:
+        self.assertFalse(is_auditable_command_line("display version"))
+
 
 class PasswordPromptTests(unittest.TestCase):
     def test_detects_password_prompt(self) -> None:
@@ -218,12 +227,12 @@ class SessionCommandAuditTests(unittest.TestCase):
             owner_username="bob",
             conn=conn,
         )
-        sess.write_stdin("display version\r")
+        sess.write_stdin("\r", audit_line="6150#display version")
         mock_audit.assert_called()
         event = mock_audit.call_args[0][0]
         self.assertEqual(event, "command")
         kwargs = mock_audit.call_args.kwargs
-        self.assertEqual(kwargs["command"], "display version")
+        self.assertEqual(kwargs["command"], "6150#display version")
         self.assertEqual(kwargs["owner_username"], "bob")
         self.assertEqual(kwargs["ne_name"], "lab")
         self.assertFalse(kwargs["redacted"])
@@ -306,6 +315,55 @@ class SessionCommandAuditTests(unittest.TestCase):
         sess.write_stdin("\r", audit_line=line)
         self.assertEqual(mock_audit.call_count, 1)
 
+    @patch("netx_api.webcrt_session_model._audit")
+    def test_prompt_sync_enter_not_audited(self, mock_audit: MagicMock) -> None:
+        conn = MagicMock()
+        conn.RETURN = "\n"
+        conn.remote_conn = MagicMock(spec=["recv_ready", "recv", "exit_status_ready", "resize_pty"])
+        del conn.remote_conn.send
+        conn.write_channel = MagicMock()
+
+        sess = WebcrtSession(
+            session_id="s-sync",
+            ne_id="ne1",
+            ne_name="lab",
+            ne_ip="1.2.3.4",
+            protocol="ssh",
+            cols=80,
+            rows=24,
+            cli_keymap=False,
+            conn=conn,
+        )
+        sess._last_prompt_line = "AL5458-ACC-6120HS#configure terminal"
+        sess._note_stdout_for_audit("AL5458-ACC-6120HS#configure terminal\r\n")
+        sess.write_stdin("\r", audit_source="prompt_sync")
+        mock_audit.assert_not_called()
+
+    @patch("netx_api.webcrt_session_model._audit")
+    def test_device_error_audit_line_rejected(self, mock_audit: MagicMock) -> None:
+        conn = MagicMock()
+        conn.RETURN = "\n"
+        conn.remote_conn = MagicMock(spec=["recv_ready", "recv", "exit_status_ready", "resize_pty"])
+        del conn.remote_conn.send
+        conn.write_channel = MagicMock()
+
+        sess = WebcrtSession(
+            session_id="s-err",
+            ne_id="ne1",
+            ne_name="lab",
+            ne_ip="1.2.3.4",
+            protocol="ssh",
+            cols=80,
+            rows=24,
+            cli_keymap=False,
+            conn=conn,
+        )
+        sess.write_stdin(
+            "\r",
+            audit_line="%Error 140303: Invalid input detected at '^' marker.",
+        )
+        mock_audit.assert_not_called()
+
     @patch("netx_api.webcrt_session_model._audit")
     def test_password_mode_redacts_command(self, mock_audit: MagicMock) -> None:
         conn = MagicMock()

web/src/components/WebTerminal.tsx

@@ -102,13 +102,55 @@ export function isPromptOnlyLine(line: string): boolean {
   return /^(?:[\w.-]+(?:\([^)]+\))*[#>]\s*|<[^>]+>\s*|\[[^\]]+\]\s*)$/.test(s);
 }
 
+const CLI_PROMPT_PREFIX = /^(?:[\w.-]+(?:\([^)]+\))*[#>]|>[\w.-]+|<[^>]+>|\[[^\]]+\])/;
+
+export function hasCliPromptPrefix(line: string): boolean {
+  return CLI_PROMPT_PREFIX.test(normalizeAuditLine(line));
+}
+
+/** Device error/warning lines must never be audited as operator commands. */
+export function isDeviceOutputLine(line: string): boolean {
+  const s = normalizeAuditLine(line).trim();
+  if (!s) return false;
+  const low = s.toLowerCase();
+  if (low.startsWith("%error") || low.startsWith("%warning")) return true;
+  if (low.includes("invalid input detected")) return true;
+  if (/^\^+\s*$/.test(s)) return true;
+  if (low.startsWith("enter configuration commands")) return true;
+  return false;
+}
+
+export function isAuditableCommandLine(line: string): boolean {
+  const s = normalizeAuditLine(line);
+  if (!s.trim() || isPromptOnlyLine(s) || isDeviceOutputLine(s)) return false;
+  return hasCliPromptPrefix(s);
+}
+
 function currentCommandLine(term: Terminal): string {
   const buf = term.buffer.active;
-  const cur = buf.getLine(buf.cursorY);
+  const y = buf.cursorY;
-  if (cur) {
+  const rows: string[] = [];
-    return normalizeAuditLine(cur.translateToString(true));
+  let sawPrompt = false;
+
+  for (let i = y; i >= Math.max(0, y - 5); i -= 1) {
+    const text = normalizeAuditLine(buf.getLine(i)?.translateToString(true) ?? "");
+    if (!text.trim()) {
+      if (rows.length) break;
+      continue;
+    }
+    if (isDeviceOutputLine(text)) break;
+    rows.unshift(text);
+    if (hasCliPromptPrefix(text)) {
+      sawPrompt = true;
+      break;
+    }
   }
-  return "";
+
+  if (!sawPrompt && rows.length === 0) {
+    const cur = buf.getLine(y);
+    return cur ? normalizeAuditLine(cur.translateToString(true)) : "";
+  }
+  return rows.join("").trimEnd();
 }
 
 function auditLineForEnter(term: Terminal | null, explicitLine?: string): string | undefined {
@@ -118,7 +160,7 @@ function auditLineForEnter(term: Terminal | null, explicitLine?: string): string
       : term
         ? currentCommandLine(term)
         : "";
-  if (!raw.trim() || isPromptOnlyLine(raw)) return undefined;
+  if (!isAuditableCommandLine(raw)) return undefined;
   return raw;
 }