Lua 5.2 allows null chars in patterns, so this hack is unnecessary

scripts/smb-psexec.nse

@@ -1348,22 +1348,7 @@ end
 local function do_replacements(mod, line)
   if(mod.replace) then
     for _, v in pairs(mod.replace) do
-
-      -- It looks like Lua doesn't like replacing the null character, so have a sidecase for it
-      if(v[1] == string.char(0)) then
-        local newline = ""
-        for i = 1, #line, 1 do
-          local char = string.sub(line, i, i)
-          if(string.byte(char) == 0) then
-            newline = newline .. v[2]
-          else
-            newline = newline .. char
-          end
-        end
-        line = newline
-      else
-        line = string.gsub(line, v[1], v[2])
-      end
+      line = string.gsub(line, v[1], v[2])
     end
   end