A massive malware distribution campaign has been detected that uses phishing emails for initial contact with businesses and Google Cloud Run for hosting the malware. A variety of banking trojans are being distributed including Astaroth, Mekotio, and Ousaban. The campaign primarily targets countries in Latin America, and as such the majority of the phishing emails are in Spanish, but Italian versions have also been detected and there are indications that the campaign is spreading to other regions including Europe and North America.

The phishing emails used in this campaign appear to be legitimate invoices, statements, and communications from government and tax agencies and include a link that the recipient must click to view the attached invoice, statement, or demand. The link directs the user to services on Google Cloud Run, which is a popular service for hosting frontend and backend services and deploying websites and applications without having to manage infrastructure. Google Cloud Run has been used for hosting malware throughout 2023 but there was a massive spike in activity that started in September 2023 and has continued through January and February.

Over the past few months, Google’s service has been proving popular with cybercriminals for hosting malware as it is both cost-effective and is generally not blocked by security solutions. If a user clicks the email link, an MSI file is downloaded onto their device. MSI files are executable files, which in this case include embedded JavaScript that downloads additional files and delivers one or more banking trojans.

The banking trojans achieve persistence through LNK files in the startup folder that execute a PowerShell command on boot that runs the infection script. The banking trojans are capable of keylogging, clipboard monitoring, screenshots, credential theft, and traffic manipulation to direct users to cloned websites of financial institutions to capture banking credentials. The Astaroth banking trojan alone targets more than 300 financial institutions as well as cryptocurrency exchanges.

To protect against this and other malware distribution campaigns, businesses need to adopt a defense-in-depth approach and should implement multiple layers of protection. The first line of defense is a spam filter or email security solution to block the initial phishing emails. SpamTitan Plus is a leading-edge anti-spam service that provides maximum protection against malicious emails. The solution has better coverage, faster phishing link detections, and the lowest false positive rate of any product, which makes it the best spam filter for businesses and an ideal MSP spam filtering solution In addition to including all leading phishing feeds to ensure the fastest possible detection of new phishing threats, SpamTitan Plus uses predictive analysis to identify suspicious URLs that have not yet been detected as malicious.

A web filter, such as WebTitan, can be used to control access to the Internet. For example, blocks can be placed on websites and certain categories of websites down to the user level, the solution prevents access to all known malicious URLs, and can be configured to block file downloads from the Internet, such as MSI files and other executable files that are often used for malware delivery.

Cybercriminals often host malware on legitimate hosting platforms which are usually trusted by security solutions, which means malicious emails may be delivered to end users. It is therefore important to provide security awareness training for the workforce. Security awareness training raises awareness of the threats that employees are likely to encounter and teaches them security best practices to help them identify, avoid, and report cyber threats. Combined with phishing simulations, it is possible to greatly reduce susceptibility to phishing and malspam emails. Data from companies that use the SafeTitan security awareness training platform and phishing simulator shows susceptibility to phishing threats can be reduced by up to 80%.

If you are looking to improve your defenses against phishing and malware, give the TitanHQ team a call to find out more about these products and to help get you set up for a free trial to put these solutions to the test in your own environment.