The Cerber ransomware is an international threat and has infected users all around the world, but researchers at Check Point observed campaigns over the past two months that focused mainly on three geographies, namely the United States, Turkey, and the United Kingdom.
Among the numerous ransomware families that emerged since the beginning of this year, only a few managed to grab enough market share to become prevalent threats, and Cerber is one of them. Spotted for the first time in late February, the ransomware stood up in the crowd because it used a VBScript that caused the infected computer to “speak” to the victim.
Since February, Cerber has received several updates, with researchers at Invincea reporting in mid-May that the malware might have been also leveraged in distributed denial of service (DDoS) attacks. Researchers noticed strange network behavior associated with the ransomware, which was calling out a large address range: from 85.93.0.0 to 85.93.63.255, and concluded that it might have been packed with new capabilities.
In early June, Invincea researchers warned that Cerber operators started using a server-side “malware factory” to evade detection. Basically, the server that delivered the payload in an observed infection campaign was generating a new hash for it every 15 seconds, thus able to trick signature-based antimalware solutions.
At the time, researchers also revealed that Cerber was most active in the United States, which accounted for almost 50 percent of infections, but that Taiwan, Japan, Australia, Brazil, Canada, Portugal, Spain, Malaysia, and Germany were also targeted countries.
Now, Check Point researchers say that while victims in the United States are indeed the targets of choice for Cerber, the ransomware is also a great threat to users in Turkey and the United Kingdom. The US accounts for 41% of infections, followed by Turkey at 15% and the UK at 9%, with Israel and Taiwan rounding up top 5 most affected countries, at 4% each.
Moreover, the security researchers observed two spikes in Cerber’s activity, one in April and another one in May, and that both were highly productive for the malware’s operators. While the U.S., Turkey and the UK were the preferred targets in these campaigns, users in other countries also fell victims to the ransomware, researchers say.
Cerber launches its attack by using Windows binaries without any parameters, and does that by injecting code into explorer.exe and calling a couple of applications. It also loads a DLL (Dynamic Link Library) used by multiple programs and, after the encryption starts, it erases shadow copies to prevent file recovery. The ransomware uses AES-265 and RSA encryption and also tampers the boot sequence, making sure that the user cannot recover the encrypted files.
After successfully encrypting the victim’s files, the ransomware deletes itself from the infected machine and uses Notepad and Google Chrome to display the ransom note. Moreover, the malware launches a watchdog that prevents uninstall attempts, thus ensuring persistency. Cerber also starts a “network search, calling a very long series of IP addresses mostly located in France.”
According to Check Point security researchers, we will see more spikes in Cerber’s activity. The ransomware is distributed via phishing emails that contain malicious attachments, and users are advised to avoid opening emails that come from unknown sources, to stay protected.
Over the past couple of weeks, Cerber has been the malicious payload in around 10 percent of the Neutrino and Magnitude exploit kits traffic. The ransomware was associated with EKs before, yet its presence in infection campaigns is more dominant now, when Angler and Nuclear are gone and Neutrino, RIG, and Magnitude have taken over the EK landscape.
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