DART: Dynamic Assessment and Repair of Tampered data in Commercial Database Applications

In a database, the results of one transaction can affect the execution of other future transactions. A single malicious transaction can damage data and in turn make the transactions that use this dirty data, malicious and so on. The complexity of attack recovery is mainly caused by a phenomenon called damage spreading. We have developed the damage assessor and damage repairer modules of an intrusion tolerant database system for accessing the extent of damage and then taking the system closer to the state in which it was expected to be if none of the transactions would have been malicious. Given a set of malicious transactions reported by an intrusion detector, the Dynamic Assessment and Repair of Tampered data (DART) system locates and repairs the damage caused by each malicious transaction on the database, along with the damage caused by any benign transaction that is affected, directly or indirectly, by a malicious transaction. While traditional secure database systems rely on preventive controls and are very limited in surviving malicious attacks by trying to just take the system in the state it was in before the attacks occurred, our system can isolate attacks, contain, assess, and actually repair the damage caused by intrusions, on the fly, in a timely manner such that sustained, selfstabilized levels of data integrity and availability can be provided to applications in the face of attacks. Experimental results of different models of DART demonstrate the performance benefits of our proposed techniques.