From db105fa9f8dc4e5d301c0eb813f5c3d7779c5e9c Mon Sep 17 00:00:00 2001
From: Jaroslav Svoboda <multi.flexi@seznam.cz>
Date: Tue, 13 May 2025 15:57:55 +0200
Subject: [PATCH] PJLik detector script

---
 scripts/pjlink.nse | 50 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 scripts/pjlink.nse

diff --git a/scripts/pjlink.nse b/scripts/pjlink.nse
new file mode 100644
index 000000000..83551d94b
--- /dev/null
+++ b/scripts/pjlink.nse
@@ -0,0 +1,50 @@
+local nmap = require "nmap"
+local shortport = require "shortport"
+local stdnse = require "stdnse"
+
+description = [[
+Detects availability of the PJLink protocol used 
+to monitor and control projectors and monitors.
+Sends a specific PJLink message and parses the response.
+]]
+
+author = "Jaroslav Svoboda"
+license = "Same as Nmap--See https://nmap.org/book/man-legal.html"
+categories = {"discovery", "safe"}
+
+portrule = shortport.port_or_service({4352}, "pjlink")
+
+action = function(host, port)
+    local socket = nmap.new_socket()
+    local status, err
+    local output
+
+    status, err = socket:connect(host, port)
+
+    -- Connect to the target host and port
+    status, err = socket:connect(host, port)
+    if not status then
+        return "Failed to connect: " .. err
+    end
+
+    -- Receive the response
+    local lines
+    status, lines = socket:receive_lines(1)
+    if not status then
+        socket:close()
+        return "Failed to receive response: " .. lines
+    end
+
+    socket:close()
+
+    stdnse.print_debug(1, "Raw response received: " .. stdnse.tohex(lines))
+    if lines:match("^PJLINK 0") then
+        output = "PJLink device detected: No authentication required."
+    elseif lines:match("^PJLINK 1") then
+        output = "PJLink device detected: Authentication required."
+    else
+        output = "No valid PJLink response detected."
+    end
+
+    return output
+end