When agencies think about up-leveling cybersecurity, many start with reinforcing their firewalls and even legacy anti-virus software. However, with the rise of ransomware attacks and catastrophic breaches, it is clear that perimeter security alone is not enough.
The recent White House Executive Order on Improving the Nation’s Cybersecurity solidifies a crucial change that federal IT leaders have been working toward for years – a fundamental shift in the cybersecurity model. Agency leaders are called to develop guidance outlining security measures for critical software, including applying the zero-trust practices of least privilege, network segmentation and proper configuration.
The National Security Agency’s recent report, “Embracing a Zero Trust Security Model,” similarly directs agencies to shift their security philosophy and architect security from the inside out with zero-trust segmentation — prioritizing critical assets rather than the perimeter.
Federal CISO Chris DeRusha, speaking at the April 22 Billington Cybersecurity Defense Summit, explained that zero-trust security concepts are “rooted in three core principles — verifying every user, validating every device and then … limiting access to intelligence.” One area implied, but not explicitly mentioned, is the back-end communication between workloads, which must be segmented or contained.
While agencies must govern who can access the network from an identity management perspective, they must also prioritize greater network visibility and segmentation. It is important they first to understand how applications and workloads connect, and only then permit traffic that is absolutely necessary.
The missing piece: Zero-trust segmentation
‘The Applications and Workloads pillar of zero-trust architecture is built on segmentation. Zero-trust segmentation prevents lateral movement of attackers once they enter the network. Using this technology, which is decoupled from the network, teams can quickly lock down key assets (i.e. applications and workloads) from other parts of the network. The more granular these segments are (e.g. micro-segmentation, nano-segmentation), the more secure agencies’ systems will be. In fact, segmentation makes the workloads and applications appear invisible to would-be attackers.
To implement zero-trust segmentation, teams should first identify which assets are critical to operations. These mission-critical, high-value applications and workloads can reside in the data center, on the cloud or in hybrid environments. Agencies also need visibility into how their applications and workloads connect to one another. Often at this stage, security teams are surprised to uncover many unnecessary — and unsecured — connections within their networks.
Once agencies have identified their most critical assets and understand the connections within their networks, they can then define, test and enforce their segmentation policy controls. Zero-trust segmentation policies use “allow lists” that indicate which applications and workloads are permitted to connect. If a connection is not explicitly stated, it is denied by default.
This is how zero-trust segmentation can stop even zero-day attacks. When an attacker tries to move laterally from the initially compromised point of entry to the rest of the network, zero-trust segmentation will block that movement automatically.
Accelerating zero-trust architecture
With rising threats, agencies’ firewalls, detect-and-defend software and perimeter-based security measures are no longer enough. Federal IT teams must assume that attackers will ultimately gain access to their networks if they have not already. Zero-trust segmentation minimizes the damage of an initial attack — preventing a small cyber incident from becoming a full-blown disaster — and limits the possibilities of future attacks.
At the Billingsgate summit, DeRusha acknowledged that zero trust may cause “challenges or disruptions in the way the workforce currently does business or accesses resources, and some may find it inconvenient.” However, the time is now for federal agencies to rise to the challenge and double-down on securing high-value assets. Our national security depends on it.
