This Joint Cybersecurity Advisory was coauthored by the Federal Bureau of Investigation (FBI), the Cybersecurity and Infrastructure Security Agency (CISA), and the Multi-State Information Sharing and Analysis Center (MS-ISAC).
The FBI, CISA, and MS-ISAC assess malicious cyber actors are targeting kindergarten through twelfth grade (K-12) educational institutions, leading to ransomware attacks, the theft of data, and the disruption of distance learning services. Cyber actors likely view schools as targets of opportunity, and these types of attacks are expected to continue through the 2020/2021 academic year. These issues will be particularly challenging for K-12 schools that face resource limitations; therefore, educational leadership, information technology personnel, and security personnel will need to balance this risk when determining their cybersecurity investments.
As of December 2020, the FBI, CISA, and MS-ISAC continue to receive reports from K-12 educational institutions about the disruption of distance learning efforts by cyber actors.
The FBI, CISA, and MS-ISAC have received numerous reports of ransomware attacks against K-12 educational institutions. In these attacks, malicious cyber actors target school computer systems, slowing access, and—in some instances—rendering the systems inaccessible for basic functions, including distance learning. Adopting tactics previously leveraged against business and industry, ransomware actors have also stolen—and threatened to leak—confidential student data to the public unless institutions pay a ransom.
According to MS-ISAC data, the percentage of reported ransomware incidents against K-12 schools increased at the beginning of the 2020 school year. In August and September, 57% of ransomware incidents reported to the MS-ISAC involved K-12 schools, compared to 28% of all reported ransomware incidents from January through July.
The five most common ransomware variants identified in incidents targeting K-12 schools between January and September 2020—based on open source information as well as victim and third-party incident reports made to MS-ISAC—are Ryuk, Maze, Nefilim, AKO, and Sodinokibi/REvil.
Figure 1 identifies the top 10 malware strains that have affected state, local, tribal, and territorial (SLTT) educational institutions over the past year (up to and including September 2020). Note: These malware variants are purely opportunistic as they not only affect educational institutions but other organizations as well.
ZeuS and Shlayer are among the most prevalent malware affecting K-12 schools.
- ZeuS is a Trojan with several variants that targets Microsoft Windows operating systems. Cyber actors use ZeuS to infect target machines and send stolen information to command-and-control servers.
- Shlayer is a Trojan downloader and dropper for MacOS malware. It is primarily distributed through malicious websites, hijacked domains, and malicious advertising posing as a fake Adobe Flash updater. Note: Shlayer is the only malware of the top 10 that targets MacOS; the other 9 affect Microsoft Windows operating systems
Figure 1: Top 10 malware affecting SLTT educational institutions
Distributed Denial-of-Service Attacks
Cyber actors are causing disruptions to K-12 educational institutions—including third-party services supporting distance learning—with distributed denial-of-service (DDoS) attacks, which temporarily limit or prevent users from conducting daily operations. The availability of DDoS-for-hire services provides opportunities for any motivated malicious cyber actor to conduct disruptive attacks regardless of experience level. Note: DDoS attacks overwhelm servers with a high level of internet traffic originating from many different sources, making it impossible to mitigate at a single source.
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