This contribution involves cooperative information systems, and more precisely interorganizational systems (IOS). Indeed, experience of real enterprises shows that most IOS interoperate today over the Web. To “ensure” security of these IOS on the Web (in particular, security of the applications they are made of), various hardware and software protection can be employed. Our work falls into the field of intrusion detection, and covers more precisely intrusion detection for Web applications. Several misuse-based intrusion detection systems (IDSs) were developed recently for Web applications, whereas, to our knowledge, only one anomaly-based Web IDS exists and works effectively to date. This one was unfortunately conceived disregarding any kind of cooperation. In previous work, we improved it to gain in sensitivity and specificity. This paper describes a cooperation feature added to the IDS, so that it is able to perform an
with other detectors, allowing coo-perative intrusion detection, as well as an
to detect distributed attacks. The first experiments in real environment show encouraging results.