[M T]

This notice came out today:

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.
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.

ZeuS [Windows] and Shlayer [OSX] are among the most prevalent malware affecting K-12 schools.

Cyber actors are causing disruptions to K-12 educational institutions—including third-party services supporting distance learning—with distributed denial-of-service (DDoS) attacks,2which temporarily limit or prevent users from conducting daily operations.

Numerous reports received by the FBI, CISA, and MS-ISAC since March 2020 indicate uninvited users have disrupted live video-conferenced classroom sessions

Unfortunately, this report (as is typical of all these reports) gives no actual numbers of incidents.  One can't know from this how many incidents there are; whether it is 0.01% of schools or 50%.

[M T]

This notice came out today:

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.
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.

ZeuS [Windows] and Shlayer [OSX] are among the most prevalent malware affecting K-12 schools.

Cyber actors are causing disruptions to K-12 educational institutions—including third-party services supporting distance learning—with distributed denial-of-service (DDoS) attacks,2which temporarily limit or prevent users from conducting daily operations.

Numerous reports received by the FBI, CISA, and MS-ISAC since March 2020 indicate uninvited users have disrupted live video-conferenced classroom sessions

Unfortunately, this report (as is typical of all these reports) gives no actual numbers of incidents.  One can't know from this how many incidents there are; whether it is 0.01% of schools or 50%.