The last few major ransomware attacks have occurred on or around holiday weekends, and IT admins and cybersecurity personnel are being urged to keep a watchful eye as we approach Labor Day Weekend.
Offices are normally closed around those holidays, so IT professionals typically don’t catch intrusions in time until systems are encrypted and hackers have already deployed a ransom note to machines.
That’s why the U.S. FBI and Cybersecurity & Infrastructure Security Agency issued a warning to organizations to be extra vigilant as another holiday weekend is just a few days away.
The agencies’ alert on Tuesday references three unnamed ransomware incidents that occurred around Mother’s Day, Memorial Day and Independence Day. The notice doesn’t name entities, but we can surmise that the events are the Colonial Pipeline attack, the JBS attack and the rEvil ransomware campaign that leveraged the Kaseya VSA software.
According to the alert, the FBI has received 2,084 ransomware complaints with more than $16.8 million in losses this year through July 31, which is close to the 2,474 incidents reported in 2020.
The most common ransomware variants observed over the last month are Conti, PYSA, LockBit, RansomEXX/Defray777, Zeppelin, and Crysis/Dharma/Phobos.
Although there is no specific threat the agencies are tracking, that recent history of large ransomware attacks around holiday weekends should be all it takes for organizations to start acting.
What IT should be doing now
The agencies are urging organizations to practice good cyber hygiene to help protect against ransomware, and they’re things most IT professionals have heard before: store backups offline, refrain from opening suspicious emails or links, secure and monitor remote desktop protocol (RDP), keep software updated, use multi-factor authentication, segment networks, use strong passwords and other basic cybersecurity practices.
However, organizations are also being urged to undergo active threat hunting to kick bad actors out of networks before ransomware is deployed.
The FBI and CISA say organizations should:
- Establish a baseline of IT environment activity to make it easier to detect anomalous activity.
- Review data logs to understand what standard performance looks like compared to malicious activity.
- Deploy intrusion prevention solutions and automated security alert systems.
- Use honeytokens and alert their use to detect lateral movement.
According to the agencies, these are indicators of suspicious activity and could be a sign that ransomware deployment is imminent:
- Unusual inbound and outbound network traffic
- Compromise of administrator privileges or escalation of the permissions on an account
- Theft of user credentials
- Substantial increase in database read volume
- Geographical irregularities in access and log in patterns
- Attempted user activity during anomalous logon times
- Attempts to access folders on a server that are not linked to the HTML within the pages of the web server
- Baseline deviations in the type of outbound encrypted traffic since advanced persistent threat actors frequently encrypt exfiltration
Develop a plan now for when a ransomware attack happens when most employees are out of the office, which should include isolating the infected system, powering off and removing devices from the network and securing your backups.