Cybercriminals have adopted a new tactic to deliver malware and conduct phishing attacks on unsuspecting internet users. They are hijacking inactive domains and using them to direct visitors to malicious websites in a form of malvertising.

Malvertising is the term given to the use of malicious code in seemingly legitimate adverts, which are often displayed on high-traffic websites.  Website owners use third-party ad networks as a way to increase revenue from their websites. Most of these adverts are genuine and will direct users to a legitimate website, but cybercriminals often sneak malicious code into these adverts. Clicking the link will direct the user to a website hosting an exploit kit or phishing form. In some cases, ‘drive-by’ malware downloads occur without any user interaction, simply if the web content loads and the user has a vulnerable device.

The new tactic uses domains that have expired and are no longer active. These websites may still be listed in the search engine results for key search terms. When user conducts a search and clicks the link or uses a link in their bookmarks to a previously visited website, they will arrive at a landing page that explains that the website is no longer active. Oftentimes, that page will include a series of links that will direct the visitor to related websites.

What often happens is these expired domains are put up for sale. They can be attractive for purchasers as there may already be many links to the website, which is preferable to starting a brand-new website from scratch. These expired domains are then auctioned. Researchers at Kaspersky found that cybercriminals have taken advantage of these auction-listed websites and have added links that direct visitors to malicious websites.

When a visitor arrives on the site, instead of being directed to the auction stub, the stub is replaced with a link to a malicious website. The study uncovered around 1,000 domains that had been listed for sale on a popular auction site, which redirected visitors to more than 2,500 unwanted URLs. In the majority of those cases, the URLs were ad-related pages, but 11% of the URLs were malicious and were mostly being used to distribute the Shlayer Trojan via infected documents that the user is prompted to download. The Shlayer Trojan installs adware on the user’s device. Several of the sites hosted malicious code on the site rather than redirecting the visitor to a different website.

These domains were once legitimate websites, but are now being used for malicious purposes, which makes the threat hard to block. In some cases, the sites will display different content based on where the user is located and if they are using a VPN to access the internet. These websites change content frequently, but they are indexed and categorized and if determined to be malicious they are added to real time block lists (RBLs).

A web filtering solution such as WebTitan can provide protection against malvertising and redirects to malicious sites. If an attempt is made to send a user to a known malicious website, rather than being connected the user will be directed to a local block page, negating the threat. WebTitan can also be configured to block downloads of risky file types from these websites.

Many organizations have implemented firewalls to prevent direct attacks by hackers, use antivirus software to block malware, and use an anti-spam solution to block attacks via email, but there is a gap in their security protections and web-based threats are not effectively blocked. WebTitan allows organizations to plug that gap and control the websites that can be accessed by employees.

For further information on WebTitan and filtering the internet, give the TitanHQ team a call. WebTitan is available on a free trial to allow you to evaluate the solution and see for yourself how you can block attempts to visit malicious web content and NSFW sites.