The Quackbot and Emotet information stealing Trojans have been showing renewed activity over the past several months and are increasingly targeting enterprises, small and medium businesses, and other organizations, Microsoft says.
Featuring similar behavior, the two malware families have typically focused on individual online banking users, but their operators seem interested in new revenue streams. They also have expanded the Trojans’ capabilities with spreading functionality to increase the chances of multiple infections in corporate networks.
Over the years, the authors of Qakbot and Emotet focused on improving their code to evade detection, stay under the radar longer, and increase the chances of spreading to other potential victims. A look at the behavior of both malware families shows many similarities, Microsoft notes in a blog post.
Both Trojans use a dropper for infection (some recent Quakbot variants are spread via exploit kits), with the dropper being responsible for injecting code into explorer.exe, dropping the payload into random folders, and ensuring persistence. The two malware families can send encrypted information to the command and control (C&C) server.
Both Qakbot and Emotet have been designed to steal victim’s information and can do so by logging keystrokes, by hooking browser and network-related APIs, and stealing cookies and certificates.
The two Trojans also have the ability to spread to accessible network shares and drives, including removable drives such as USB sticks. They can also spread via default admin shares and shared folders and can attempt to brute-force attacks using enumerated Active Directory accounts and can use Server Message Block (SMB) to infect other machines.
According to Microsoft, while Windows 10 already includes a variety of features to keep users safe from malware families such as Qakbot and Emotet, enterprises can apply a series of steps to mitigate possible infections and remove the threats from their networks.
The first step would be to cut the infected machines from the network until they have been cleaned (an operation that can be easily performed with the help of Windows Defender Advanced Threat Protection, the company says) and to stop sharing folders that show sign of infection. Good credential hygiene should help as well.
As a second step, locking down the Scheduled Tasks folder and disabling autorun should prevent the malware from automatically running on the compromised machines. The next step would be to remove the Qakbot and Emotet from the infected systems, as well as any other related malware accompanying them.
Finally, enterprises are advised to determine the initial infection vector and take steps to address it, as well as to enable real-time protections on all machines in the network to prevent future infections. Setting email policies to block messages that might be carrying malware, protecting domain credentials and educating employees on such threats should also help prevent future infections.