How to prevent XML eXternal Entity (XXE) attack during .net deserialization
<p>We are doing  security analysis of our code using veracode and its showing XXE flaw for below code, specifically where Deserialize() is invoked. How can we prevent serializer from accessing external entities. My attempt below to set XMLresolver to null for XMLReader is not working.</p>

<pre><code>    public static T DeserializeObject(string xml, string Namespace)
    {
        System.Xml.Serialization.XmlSerializer serializer = new System.Xml.Serialization.XmlSerializer(typeof(T), Namespace);

        MemoryStream stream =
                new MemoryStream(Encoding.Default.GetBytes(xml));
        XmlReaderSettings settings = new XmlReaderSettings();

        // allow entity parsing but do so more safely
        settings.DtdProcessing = DtdProcessing.Ignore;
        settings.XmlResolver = null;

        using (XmlReader reader = XmlReader.Create(stream, settings))
        {
            return serializer.Deserialize(reader) as T;
        }
    }
</code></pre>

<p>Can anyone suggest what I might be missing or if there is something else to try.</p>