Exploit — Webresource.axd

Apply all .NET Framework updates, especially and subsequent security rollups. Modern .NET Framework versions (4.5+) are not vulnerable to the cryptographic forgery issue, but they still require proper configuration.

Block suspicious patterns in the d parameter: webresource.axd exploit

These tools allowed even unskilled attackers (script kiddies) to point a script at a target URL and automatically run the Padding Oracle Attack. The script would chatter away for a few minutes, requesting thousands of variations of the URL, and eventually spit out the decrypted web.config file. This ease of use led to a massive wave of compromises in the early 2010s. Apply all

Configure in your web.config to return the same error page and status code for all failures. Use redirectMode="ResponseRewrite" to prevent timing attacks. The script would chatter away for a few

One reason the WebResource.axd exploit remains a keyword in security circles is the availability of automated tools. Shortly after the vulnerability was disclosed, tools like and VSPlugin were released.

Decryption failed due to "bad padding."