The spread of the coronavirus (COVID-19) pandemic has driven many enterprises to take proactive steps to maintain business continuity. One of the most prevalent of those steps is the sudden shift of employee bases to work-from-home models. For security teams, this has changed both the nature of the attack surface they must defend and the tactics of opportunistic threat actors.
ReliaQuest’s threat management team is closely monitoring the changing situation across the environments of hundreds of the world’s largest brands. We recommend enterprises focus on three areas to optimize their visibility and ability to respond to threats as workforces go remote:
1.) Monitor Changes in Remote Access Trends
As user behavior changes with an increase in remote work, expect any established baselines for remote authentications to become skewed. The most common value to track is the source IP address from each users’ authentication. However, there is more variance when most employees can work remote; they are not restricted to a specific location and can usually travel and work from anywhere. More remote authentications will be sourcing from a variety of networks such as home Internet Service Providers (ISPs), potentially in different states or countries. We expect there will be an increase in false positive alerts for remote access anomalies as the users move outside the office.
Attackers may also use the increased noise as cover to carry out attacks against remote authentication portals and Virtual Private Networks (VPN), using techniques such as password spraying and guessing. It is important to continue to monitor for these types of anomalies and attacks and quickly remediate any alerts.
2.) Maximize Visibility Across Networks and Endpoints
As users move off the network, they also move away from devices that log their activity. Therefore, working remotely creates new challenges for logging network and endpoint activity and can result in large visibility gaps.
Endpoint agents will still need to send their logs back to a central server for collection and monitoring. This includes antivirus, Endpoint Detection and Response (EDR) tools, and even the native operating system itself. Most agents send their logs to on-premise server, in which case a device off the internal network will require a VPN to send its logs. If remote users are not consistently connecting to the VPN, the logs will collect on their device and not be sent until they reconnect, delaying detection and response.
Network visibility will also be affected, as traffic from a device not connected to the VPN will not route through on-premise logging devices such as firewalls and web proxies. This is also true for split-tunnel VPNs, which do not send internet-bound traffic over the VPN connection where it would be logged. This opens the possibility for threat activity to be missed, such as web-based malware, malicious downloads, and exfiltration.
One positive trend: the shift to cloud infrastructure. While on-premise endpoint and network technologies are subject to visibility gaps, cloud products offer an “always-on” monitoring approach that sends logs directly to the cloud for storage. Shared cloud services such as Office 365 will always be able to log user activity since the interaction occurs on the server, not the endpoint. Lastly, solutions such as Email Security Appliances will provide needed visibility into the surge of phishing related to the COVID-19 virus.
3.) Shore Up “Bring Your Own Device” Policies
Visibility is even more challenging when organizations adopt a “Bring Your Own Device” (BYOD) policy, which allows employees to utilize personal assets for remote work. These assets may not be subject to the same controls as corporate assets and often lack logging agents, security tools, and patches. If employees need to access internal resources, these assets connect into the corporate network most commonly in two ways: VPN or Virtual Desktop Infrastructures (VDI). However, allowing personal assets to access the network through these methods introduces new risks for the organization. For example, an already-infected machine can provide attackers with a pivoting opportunity.
Profiles can be implemented through many BYOD solutions which enable security software and configurations to be pushed to the machine. This allows security teams to pull necessary audit and security logs from these devices. We recommend enabling features that pre-check the assets for recent security updates and configurations, as well as perform anti-virus scans before being allowed to connect into the network.
Adapting Your Security Model for Enable Work-From-Home At Scale
ReliaQuest and its GreyMatter platform are already enabling the world’s leading enterprises to securely shift to remote work models while maximizing overall threat detection and response capabilities. Learn more about GreyMatter.
The content for this post was contributed by Chris Martinez and Kevin Kaminski of ReliaQuest’s threat management team.