From e278afa57d950dcbd6c91c72733cd552a01ef20a Mon Sep 17 00:00:00 2001
From: dmiller <dmiller@e0a8ed71-7df4-0310-8962-fdc924857419>
Date: Wed, 9 Sep 2020 17:16:13 +0000
Subject: [PATCH] Handle too-short response in s7-info. See #2117

---
 scripts/s7-info.nse | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/scripts/s7-info.nse b/scripts/s7-info.nse
index c9280b7d4..db58c7cf7 100644
--- a/scripts/s7-info.nse
+++ b/scripts/s7-info.nse
@@ -128,6 +128,10 @@ local function second_parse_response(response, output)
       -- change offset to 4, this is where most of valid PLCs will fall
       offset = 4
     end
+    if #response < 142 + offset then
+      stdnse.debug1("Short response cannot be parsed.")
+      return nil
+    end
     -- parse system name
     output["System Name"] = string.unpack("z", response, 40 + offset)
     -- parse module type