DNS fast flux/anomaly detection
The idea is to detect malware and other things by collecting the DNS request and their answer and detecting anomaly. For example, if an host is making a lot of request to a domain.
First part of the job on Suricata is to log all requests and their answer. Then analysis can occurs in the database.
This is a work under progress linked with a third party contract. It permit to store exchanged files on disk for some application level protocol. It is possible to say: “store the file, if the content type is different from the extension”. File extraction works currently on HTTP. It focus on POST request to detect uploaded file.
This aims at detection of regular behaviours which are often linked with command control connection. For example, triggering an alert if a specific DNS request is done every five minutes.
HTTP keyword improvement
HTTP keywords improvement are discussed, some specific keywords could be added to avoid the cost of pcre. A two parameters header match is suggested to support all possible keyword.
Discussion is about logging the normalised application level content. Currently, only the packet triggering the lart is loggued and thus the information about why suricata has logged is lost. This is thus interesting to log the reconstructed application level message to permit the analyst to analyse the reason of the alert.
Regarding the output module, it could be interesting to adds support for CEE logging which would be able to support the resulting composite alert. For performance reason, a barnyard output of this composite alert is interesting. It may be needed to suggest some change to support this application level alert.