The disruption to learning from a pandemic that has lasted more than a year is bad enough, but many schools have experienced even more disruption just as many have opened their gates and allowed students back into classrooms.  The SARS-CoV-2 virus may have been brought under control thanks to lockdown measures and the rollout of vaccines, but another type of virus is proving to be a major threat – ransomware.

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FBI Warns of Targeted Ransomware Attacks on K12 Schools and Higher Education

Ransomware attacks on schools have been stepped up in recent months and schools and higher education institutions are being actively targeted. In the United States, the Federal Bureau of Investigation recently issued an alert to the education sector warning about the threat of attacks involving Pysa ransomware. The threat actors behind this ransomware variant have been actively targeting K12 schools, higher education, and seminaries. Buffalo City Schools were forced to close their schools in March following a ransomware attack that crippled their IT systems, just before students were about to return to classrooms as part of a phased reopening of schools.

The ransomware is deployed manually after compromising the network. The attack often starts with a phishing email, which gives the attackers the foothold in the network they need. They then conduct reconnaissance, move laterally, and compromise entire networks before deploying their ransomware.

Prior to running the encryption routine that cripple IT systems, the attackers steal sensitive data. Files containing student information are obtained and threats are issued to publish or sell the stolen data if the ransom is not paid. The gang, like many others, has a leak site and routinely follows through on the threat.

Spike in Ransomware Attacks on UK Schools

Ransomware attacks on schools are not confined to the United States. The Pysa ransomware gang is also targeting schools in the United Kingdom and many other countries, and the Pysa gang is not alone. Many other ransomware operations have been attacking schools.

Following a rise in ransomware attacks on UK schools, the UK’s National Cyber Security Centre (NCSC) issued an alert to educational institutions about the growing threat of attacks. NCSC has observed an increase in ransomware attacks on schools from late February 2021, which coincides with students returning to classrooms after an extensive period of school closures due to the pandemic.

The NCSC said there is no reason to believe that these attacks are being conducted by the same criminal group. This appears to be the work of multiple threat groups. These attacks have caused varying levels of disruption, including rendering entire networks inoperable, disabling email and websites, and hampering the ability of students to learn. In some cases, students have lost coursework as a result of the attacks, records of COVID-19 tests have been rendered inaccessible, and school financial records have been lost.

Unfortunately, even paying the ransom is no guarantee of being able to recover encrypted files. While the attackers claim they have the keys to unlock the encryption, they may not be provided. There is also no guarantee that stolen data will be deleted when the ransom is paid. There have been many cases when further ransom demands have been issued after payment has been made.

Adopt a Defense in Depth Strategy to Block Ransomware Attacks

The Department for Education (DfE) has recently urged UK schools to review their cybersecurity defenses and take the necessary steps to harden their defenses against cyberattacks. The NCSC explained that there is no single cybersecurity solution that will provide protection against these attacks. What is required is a defense in depth approach to security.

Defense in depth means implementing multiple overlapping layers of security. If one layer fails to block an attack, others are in place to block the attack.

In practice this means good patch management – applying updates to software, firmware, and operating systems promptly. Antivirus software must be installed on all devices and be kept up to date. Spam filtering solutions should be implemented to block the phishing emails that give the attackers access to the network. These filters can also be used to block email attachments that are not typically received.

Web filters should be used to block access to malicious websites. These filters inspect the content of websites to determine if it is malicious. They also categorize web content, and the filters allow schools to carefully control the types of content that students and staff can access to reduce risk.

Multi factor authentication should be implemented on all remote access points and email accounts, remote access ports that are not being used should be blocked, and a VPN should be used for remote access. The rule of least privilege should be applied for remote access and all staff and student accounts.

It is also recommended to prevent all non-administrator accounts from being able to install software, office macros should be disabled, as should autorun on portable devices.

It is also vital that all files are backed up daily and backups tested to make sure file recovery is possible. Backups should be stored on non-networked devices and must not be accessible from the systems where the data resides. Ideally, multiple backup copies should be created with at least one stored on an air-gaped device.