Changed output for the sharkfest lua scripts

wireshark/sharkfest_scripts/tcp_syn_scan.lua

@@ -0,0 +1,161 @@
+--
+-- (C) 2021 - ntop.org
+--
+-- This is going to be an example of a lua script that can be written for cybersecurity reasons.
+-- TCP No Data Exchanged:
+-- The TCP No Data Exchanged is a really important script to check if flows are suspicious
+-- Because usually, a typic TCP traffic, have some payload and it is not 0. Instead, in some attacks,
+-- for example the TCP SYN Scan or SYN Flood, there is a lot of TCP traffic with no data.
+
+local f_tcp_traffic = Field.new("tcp")
+local f_tcp_payload = Field.new("tcp.len")
+local f_ip_src = Field.new("ip.src")
+local f_ip_dst = Field.new("ip.dst")
+local f_port_src = Field.new("tcp.srcport")
+local f_port_dst = Field.new("tcp.dstport")
+local f_conn_fin = Field.new("tcp.flags.fin")
+
+--############################################
+
+local function getstring(finfo)
+	local ok, val = pcall(tostring, finfo)
+	if not ok then val = "(unknown)" end
+	return val
+end
+
+--############################################
+
+local function processResponse(tcp_table, src, src_port, dst, dst_port, payload)
+    local key = src .. " -> " .. dst
+
+    -- Create the table entry if needed
+    if not tcp_table[key] then
+        local key2 = dst .. "->" ..  src
+        if not tcp_table[key2] then
+            tcp_table[key] = {
+                payload = 0,
+                fin = false,
+                contacted_ports = 0,
+                dst_ports = {}
+            }
+        else
+            -- Switching src and dst ports and ip
+            local tmp = dst
+            key = key2
+            dst = src
+            src = tmp
+            tmp = src_port
+            src_port = dst_port
+            dst_port = tmp
+        end
+    end
+
+    -- Increase the stats
+    tcp_table[key]["payload"] = tcp_table[key]["payload"] + getstring(payload.value)
+
+    if not tcp_table[key]["dst_ports"][dst_port] then
+        tcp_table[key]["dst_ports"][dst_port] = 1
+        tcp_table[key]["contacted_ports"] = tcp_table[key]["contacted_ports"] + 1        
+    end
+
+    if getstring(f_conn_fin().value) == true then
+        tcp_table[key]["fin"] = true
+    end
+
+    return tcp_table
+end
+
+--############################################
+
+local function processPackets(pinfo,tvb, tcp_table) 
+    -- Call the function that extracts the field
+    local tcp_traffic = f_tcp_traffic()
+    local tcp_payload = f_tcp_payload()
+
+    --Check if there is an HTTP request or reply
+    if tcp_traffic then
+        local src = getstring(f_ip_src().value)
+        local dst = getstring(f_ip_dst().value)
+        local src_port = getstring(f_port_src().value)
+        local dst_port = getstring(f_port_dst().value)
+
+        tcp_table = processResponse(tcp_table, src, src_port, dst, dst_port, tcp_payload)
+    end
+
+    return tcp_table
+end
+
+--############################################
+
+local function tcpSynScan()
+	-- Declare the window we will use
+	local tw = TextWindow.new("TCP No Data Exchanged")
+
+	local tcp_table = {}
+
+	local tap = Listener.new();
+
+	local function removeListener()
+		-- This way we remove the listener that otherwise will remain running indefinitely
+		tap:remove();
+	end
+
+	-- We tell the window to call the remove() function when closed
+	tw:set_atclose(removeListener)
+
+	-- This function will be called once for each packet
+	function tap.packet(pinfo,tvb)
+        tcp_table = processPackets(pinfo,tvb, tcp_table)
+	end
+
+	-- This function will be called once every few seconds to update our window
+	function tap.draw(t)
+		tw:clear()
+
+        local dangerous_flows = {}
+        local ok_flows = {}
+		
+        for flow, data in pairs(tcp_table) do
+			local payload = data["payload"]
+			local contacted_ports = data["contacted_ports"]
+
+            if tonumber(payload) == 0 and tonumber(contacted_ports) > 10 then
+                dangerous_flows[#dangerous_flows + 1] = data
+                dangerous_flows[#dangerous_flows]["flow"] = flow
+            else
+                ok_flows[#ok_flows + 1] = data
+                ok_flows[#ok_flows]["flow"] = flow
+            end
+		end
+
+        if #dangerous_flows > 0 then
+            tw:append("------------- DETECTED TCP SYN SCAN -------------\n\n")
+            tw:append("TOT SUSPICIOUS FLOWS DETECTED:\t" .. #dangerous_flows .. "\n")
+        else
+            tw:append("------------- TCP SYN SCAN NOT DETECTED -------------\n\n")
+        end
+
+        tw:append("TOTAL FLOWS DETECTED:\t\t" .. #dangerous_flows + #ok_flows .. "\n\n")
+        
+        for _, data in pairs(dangerous_flows) do
+            local flow = data["flow"]
+			local payload = data["payload"]
+			local contacted_ports = data["contacted_ports"]
+
+            tw:append(flow .. ":\n\tTotal ports scanned:\t" .. tostring(contacted_ports) .. "\n\n");
+        end
+	end
+
+	-- This function will be called whenever a reset is needed
+	-- e.g. when reloading the capture file
+	function tap.reset()
+		tw:clear()
+		tcp_table = {}
+	end
+
+	-- Ensure that all existing packets are processed.
+	retap_packets()
+end
+
+-- Register the menu Entry
+register_menu("Sharkfest/TCP SYN Scan", tcpSynScan, MENU_TOOLS_UNSORTED)