As attack surfaces expand exponentially, security professionals need to broaden their focus beyond just stopping attackers, to finding malware inside their organizations and preventing data from leaving their networks. Analyst firm Gartner's report on 2015 tech trends predicts that digital businesses will find it impossible to maintain a 100% secured environment and will need to opt for risk assessment and mitigation tools instead.
“The old approach to security that emphasizes securing access is inadequate for digital business,” the report notes. “Security must be enhanced inside the enterprise boundaries and inside the applications themselves.”
Security teams have traditionally turned to penetration testing to perform mock attacks on computer systems in order to locate vulnerabilities that could be exploited. Entry points can occur on any externally facing part of the network including web servers, email servers, and firewalls. The practice has been effective but is dated, coming into existence in the 1960s and 1970s, when defense contractors and US defense agencies began the practice of systematically simulating attacks on the Pentagon's network, among other targets.
In 2015, with the rise of the Internet of Things and the continuing impact of Bring Your Own Device (BYOD), the number of entry points to networks has grown exponentially in size and complexity. Policing the periphery of the network is no longer enough: It’s a foregone conclusion that infected devices—perhaps infected on another network, but infected nonetheless—will connect to what used to be thought of as the secure side of most networks.
The nature of attacks has changed as well. Cyberattacks were once a way of gaining notoriety in the hacker community, with attacks that were noisy and boastful in nature. Now, whether attackers are motivated by monetary gain or political interest, the nature of attacks has become less visible and more sophisticated. For example, advanced persistent threats (APTs) are common now. APTs invisibly infiltrate the network, lie undetected, and then communicate with offsite command-and-control centers to subversively operate on the network.
These days, most security professionals would concede that their networks have become more vulnerable, particularly with the rise of mobile device connections. Given the likelihood that attacks have already infiltrated the network, what’s next?
In addition to the network’s perimeter, security professionals need to focus on points where communication leaves the network and expand the scope of penetration testing to include the possibility—perhaps the inevitability—that compromised devices are connected to the network. Often, this external communication is via the Domain Name System, or DNS. APTs often use DNS to call home and receive instructions, at which point they may download additional malware payloads and steal sensitive information—possibly tunneled through DNS.
By monitoring DNS traffic, looking both for known malicious destinations as well as suspicious traffic patterns, and disrupting this communication, companies can prevent valuable business and personal information from leaving the network. If an APT is prevented from “calling home,” it loses its potency. It may lie on the network for months undetected, but without a connection to the outside world, the damage it can do is very limited. This way, no matter how large the perimeter of a network grows, security teams can effectively manage key points of communication—including DNS—to render APTs ineffective.