Monday, June 6, 2011

The value of an Audit Trail for blocked REST API calls

[ Update: Axway acquired Vordel in 2012 and the new name for the Vordel Gateway is the Axway API Gateway ]

An often-overlooked aspect of security is the Audit Trail. In the case of a REST API, we want to know not only that a REST API call was blocked, but why it was blocked.

Let's take a look at the Real-Time Monitoring from the Vordel Gateway, deployed to manage a REST API. We see the orange spike indicating that an API call was blocked:

The key to looking up the Audit Trail is the message ID. Vordel users will be familiar with this ID as the ${id} attribute which is automatically created for each message in the Gateway. In this case, I highlight the message ID for the offending message and copy it:

Then I tab over to the Audit Trail and paste the Message ID into the search form:

When I press the Search button, I can see the message content, including the SQL Injection attempt which I have circled. The Vordel Gateway detected and blocked this attack against the REST API.

So, it's important to know not only that a REST API call was blocked, but why it was blocked and what the REST API call actually was. This is the value of an audit trail. In addition, the Audit Trail logs may be signed, and the key used to sign them may be stored on a HSM (Hardware Security Module). All of the screenshots were taken from the Vordel evaluation image, which you can request from