diff --git a/protocols/s7/src/main/resources/protocols/s7/s7.mspec b/protocols/s7/src/main/resources/protocols/s7/s7.mspec
index 3a5e34e1b31..0dcb81b3de0 100644
--- a/protocols/s7/src/main/resources/protocols/s7/s7.mspec
+++ b/protocols/s7/src/main/resources/protocols/s7/s7.mspec
@@ -17,6 +17,9 @@
  * under the License.
  */
 
+// https://blog.viettelcybersecurity.com/security-wall-of-s7commplus-part-1/
+// https://blog.viettelcybersecurity.com/security-wall-of-s7commplus-3/
+
 ////////////////////////////////////////////////////////////////
 // IsoOnTcp/TPKT
 ////////////////////////////////////////////////////////////////