added function to report leaked server version from header field

Signed-off-by: prateekrana-getastra <prateek.rana@getastra.com>

Author: Prateek1519

CHANGELOG.md

@@ -18,6 +18,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ### Changed
 - standalone/enableDebugLogging.js > Updated for more recent logging funtionality.
 - Update JS scripts to use passed singleton variables (control, model, view) if available (>= ZAP 2.12.0).
+- passive/Server Header Disclosure.js > Updated to check that the Server Header contains something that looks like a semantic version component.
 
 ## [14] - 2021-11-01
 ### Added

passive/Server Header Disclosure.js

@@ -1,4 +1,5 @@
 // Server Header Check by freakyclown@gmail.com
+// Server Version leaks found via header field by prateek.rana@getastra.com
 
 function scan(ps, msg, src) 
 {
@@ -15,9 +16,27 @@ function scan(ps, msg, src)
     var url = msg.getRequestHeader().getURI().toString();
     var headers = msg.getResponseHeader().getHeaders("Server")
 
-    if (headers != null)
+    if (headers != null && containsPotentialSemver(headers))
     {
-        ps.raiseAlert(alertRisk, alertConfidence, alertTitle, alertDesc, url, '', '', '', alertSolution,headers, cweId, wascId, msg);
+        var headersString = headers.toString();
+        ps.raiseAlert(alertRisk, alertConfidence, alertTitle, alertDesc, url, '', '', '', alertSolution, headersString, cweId, wascId, msg);
     }
 
 }
+
+function containsPotentialSemver(content) {
+
+    var versionPattern = new RegExp("(?:\\d+\\.)+\\d+");
+
+    try {
+        var res = versionPattern.exec(content);
+        if (res == null || res.join('') === ""){
+            return false;
+        }
+        return true;
+    }
+
+    catch (err) {
+        return false;
+    }
+}