title: How to secure applications that are vulnerable to quotation character without changing code?
body: <p>I have discovered that in our network the security guys blocked GET requests that contain characters like &lt;, >, ", ' and their encoded equivalents. These are character that are required by many web applications to function properly and even when building new apps we have to take this restrictive rule into account. We have to do different sort of hacks to make out-of-the-box or even new apps work. When I discussed the matter it turned out that they have many old apps at hand that have vulnerabilities that can be triggered by these characters (SQL Injection,...) and they don't have access to people to solve these issues so instead they have decided to block these request all together. Still I find it hard to believe if there is no other way around this. </p>
  
  <p>I am wondering how other enterprises achieve the same without putting such a limitation in place or to be precise:
  <strong>How can we secure those old web application without changing their source code and blocking all requests even for new applications that do not have these vulnerabilities, in a cost effective way?</strong></p>