Malware is often distributed via email or websites linked in emails, and advanced email security solutions such as SpamTitan Plus can protect you by preventing the messages from reaching inboxes. SpamTitan Plus uses dual antivirus engines to detect known malware and sandboxing to identify and block zero-day malware threats. SpamTitan Plus also rewrites URLs, uses predictive analysis to identify suspicious URLs, and blocks those URLs to prevent users from reaching the websites where malware is hosted. To get around email security solutions, cybercriminals use other methods for making initial contact with end users, and instant messaging services are a popular alternative.

Researchers at Cybereason recently identified a malware distribution campaign that distributes a Python-based information stealer via Facebook messages. The infostealer has been dubbed Snake and has been developed to steal credentials and other sensitive information. The campaign was first detected in the summer of 2023 and targets businesses. The messages use lures such as complaints and offers of products from suppliers to trick users into visiting a link and downloading a file. As is common with malware distribution campaigns, the threat actor uses legitimate public repositories for hosting the malicious file, such as GitHub and GitLab. The file to which the user is directed is a compressed file and, if extracted, will lead to the execution of a first-stage downloader. The first-stage downloader fetches a second compressed file,  extracts the contents, and executes a second downloader, which delivers the Python infostealer.

Three different variants of the infostealer have been identified, all of which gain persistence via the StartUp folder. Each variant targets web browsers, including Brave, Chromium, Chrome, Edge, Firefox, Opera, and the Vietnamese CoC CoC browser, with the latter and other evidence suggesting that the campaign is being conducted by a Vietnamese threat actor. All three variants also target Facebook cookies. The gathered data and cookies are exfiltrated in a .zip file via the Telegram Bot API or Discord.

One way of blocking these attacks is to use a web filter to block access to instant messaging services that are not required for business purposes, including Facebook Messenger. With WebTitan it is possible to block Messenger without blocking the Facebook site, and controls can be implemented for different users to allow users with responsibility for updating the organization’s social media sites to access the platforms while preventing access for other users. It is also a good practice to use WebTitan to block downloads of executable files from the Internet to prevent malware delivery and stop employees from downloading and installing unauthorized software.