Safeguarding Schools Against RDP-Based Ransomware

The FBI has issued a warning to US K-12 school districts, advising them that they are being targeted by cyberthieves and should take extra precautions to secure their networks. With schools around the world responding to COVID-19 restrictions by moving to online learning, millions of students and teachers are logging on to school networks for classes and assignments. Many of them use unmanaged computers that are prone to vulnerabilities, creating countless opportunities for cybercriminals to use those devices as an attack vector to the internal network.

While the pandemic has opened new opportunities for cybercriminals, attacks on K-12 schools are nothing new. In fact, they have been on the rise for some time. The K-12 Cybersecurity Resource Center's Year in Review for 2019 reported 348 publicly disclosed "incidents" at schools, three times as many as in 2018. In 2020–2021, the FBI anticipates a major increase in attacks as schools begin to open, even as many states still struggle to contain the novel coronavirus, while others that were initially successful are battling a second wave following reopenings.

Most school districts now acknowledge that things will not be back to normal this fall, and they are planning hybrid learning solutions for the school year. Hackers are delighted with this development since distance learning is often implemented using Microsoft's Remote Desktop Protocol (RDP), one of the prime targets for cybercriminals, aiming for quick gains. Their primary tactic: install ransomware that locks up data until ransoms are paid. Recently, in June 2020, the University of California San Francisco School of Medicine paid a ransom of over $1 million to regain access to important scientific data.

While a K-12 school or school district may not have data worth millions, cybercriminals know that schools often lack the resources large corporations deploy to guard against cyberattacks, which makes them prime targets. One specific attack vector the FBI has warned about is Ryuk ransomware, which is deployed via RDP endpoints, specifically students, parents, and teachers in the K-12 environment. Ryuk uses a sophisticated type of data encryption that targets backup files. Once the end user has been infected, that person can propagate the virus to the school's servers, where it can cause havoc.

"Vaccinating" Against Ransomware Infections
There are relatively simple and affordable steps to empower educational organizations providing distance learning, while keeping schools and districts safe from cyberthreats. The FBI recommends the following five steps:

Step 1: Backup your data. Make sure your backups cover your most important files.

Step 2: Secure your backups. Backups should not be connected to the computers and networks that are being backed up because anything that's connected to your network, including your backup files, can be encrypted in a ransomware attack. Also, if a good, up-to-date backup is available, there's no need to pay ransomware because all data can be quickly restored.

Step 3: Make sure that all software and operating systems are up to date and security patches are installed. It's important to make sure that all end users are updating their software, including parents, teachers, administrators, and students, in addition to software on the school's server. (Good luck with that!)

Step 4: Monitor all remote connections and software. Identify unusual activity, such as failed login attempts from any administrator-level account.

Step 5: Use two-factor authorization for login. Also apply "least privilege" controls, which allow users to access only the data and applications they need. This includes, for instance, allowing just read-only access, without the ability to alter content in any way, if students have no need to write while using a specific application.

Best Backup and Remote Access Security Practices
There are two effective ways to secure your backups from ransomware demands. The first is to use a backup that is completely offline. Why? Because if the backup is connected to the network, it likely won't help you; hackers now deploy tools that allow them to encrypt your backups as well. A disk backup may seem old-fashioned, but it's still an effective way to have a restorable backup in the event of a ransomware attack. It's also important to keep records of backups, so you can easily find the one created most recently, prior to the attack. Another advantage of storing disk backups off-site is they are available in the event of disaster such as fires or floods.

The second way to secure backups is to use cloud backup services. These services are designed with disaster recovery in mind and generally offer file versioning, which means you can restore from a backup that was done before your data was hijacked by ransomware and preserve your file structure, which makes the restore process much simpler.

Advanced Remote Access Software
Look for server-based software that is easy to control and maintain. Your IT professionals have the expertise to manage and deploy patches, but getting students, staff, and parents to update software that's installed on their devices, consistently and promptly, is a much greater challenge. The right software can be a lifesaver here. For example, some solutions are browser-based and, as a result, do not require software to be deployed on the devices themselves. Also, look for software that allows you to apply least-privilege access principles, giving different users varying levels of access (read versus write) to various applications and IT resources on servers.

Today's investment in securing online learning will also return long-term benefits. The pandemic has accelerated the digital transformation journey for many, and schools are likely to continue incorporating distance learning as an adjunct to the traditional classroom. So, getting it right today will protect schools, and the communities they serve, for years to come.