There has been a change in the distribution method of PikaBot malware, which is now being pushed in a malvertising campaign. Previously PikaBot was only distributed via phishing emails. PikaBot malware was first identified in early 2023 and is a modular malware Trojan that consists of two components: a loader and a core module. The malware allows the operator to gain remote access to compromised systems and execute a range of commands, including shell commands and fetching and running EXE or DLL files. The malware also allows downloads of additional malware payloads and post-compromise tools. The malware is known to be used by a prolific threat actor tracked as TA577, with infection leading to the deployment of Cobalt Strike.

The malvertising campaign uses Google Ads for AnyDesk, a remote desktop application popular with businesses. Google has security checks in place to prevent malicious adverts from being displayed and these are being bypassed by using a tracking URL with a legitimate marketing platform, with the custom domain for the redirect protected by Cloudflare. The malicious adverts are displayed when users search for popular software such as Zoom, Advanced IP Scanner, and WinSCP.

If the Ad is clicked by a user, they are directed to a spoofed AnyDesk download site that will deliver an MSI installer hosted on Dropbox. Checks are also performed before redirection to the malicious site, with redirection not occurring if fingerprinting checks determine the request is originating from a virtual machine. Before the MSI download is initiated, another check is performed to test whether the request is coming from a virtual environment. On download, Pikabot uses an injector to run anti-analysis tests and will only decrypt and inject the core module payload if these checks are passed, otherwise, execution is aborted.

The use of malvertising in malware campaigns is increasing and this initial access vector is often successful as most security awareness training programs concentrate on phishing. It is important to ensure that malvertising is covered in security awareness training sessions and that employees are told about the risks of downloading software and are made aware of the checks they should perform to make sure the source of the software is legitimate.

Businesses can further protect themselves against malware distribution via the internet with a DNS filter. The WebTitan DNS filter can be used to control the web pages that can be accessed by employees. Access can be restricted to whitelisted sites, and websites can be easily blocked by category. WebTitan is constantly updated by multiple threat intelligence feeds and will block access to all URLs known to be used for malware distribution. While this malvertising campaign involves many checks to determine if a web filter is accessing the content, which may result in the content being accessible, WebTitan can be configured to block the downloading of certain files from the Internet, including executable files such as MSI files. Not only will this help to prevent malware downloads, it will also allow IT teams to curb shadow IT – unauthorized software downloads by employees – which are a security risk.

The WebTitan DNS Filter and the SafeTitan Security Awareness Training Platform are both available on a free trial and product demonstrations can be arranged on request. For further information give the TitanHQ team a call.