Database discovery is the act of locating databases on a network. Years ago, this was simple because companies had only one or two databases. Now just about every application created relies on database services to provide data integrity and transactional consistency.As is common with SQL Server, a single installation can support hundreds of database instances. With virtualization and mirroring in wide use for disaster recovery, these databases move and propagate automatically. Many desktop applications embed "lite" versions of enterprise databases, scattering databases across the endpoint. With companies having geographically disperse locations on networks further segmented by business function, finding and itemizing different databases is a complex task.

Each database in an organization poses a security risk. The risk is both in the data it houses and as a potential target for attackers. Forensic analysis of major data breaches has proved highly sensitive data has been stolen from unsecured test servers, and databases with poor security are leveraged to attack other database installations. Unless the database and data security settings have been adjusted from their default settings, they are not secure.

Discovery is not really a security operation per se, but finding databases is useful for a wide variety of security and operational tasks. The business motivation for database discovery is to itemize the databases in order to understand where these assets reside. Once discovered, this information is used to verify they conform to security policy through assessment. It is used by operations staff to check licensing and patch revision levels. It is used for data discovery tools to locate sensitive information. Databases communicate with other applications by setting themselves up to listen for communication requests at a specific location called a network "port." Most database discovery tools work by performing a scan of network ports on a server. As databases default (Oracle is port 1521, SQL Server is port 1433), automated network scanning tools will call these locations to see if there is a service listening. If so, it assumes a database is present. Most automated scanning tools accept a TCP-IP address range as well as port address ranges, and will look for specific database types. The scanner will attempt to communicate with the port and, depending on the response, can determine database type and possibly version.

If your company has only a handful of production databases, then database discovery is probably not appropriate for you. But if your firm has many applications and/or heterogeneous databases, then discovery tools are very helpful in managing database security. Both commercial and free tools are available, with variations on ease of use, speed of scan, and integration capabilities. Plan on running periodically to verify what you have, and locate new databases that have popped up.

Adrian Lane is an analyst/CTO with Securosis LLC, an independent security consulting practice. Special to Dark Reading.