The cybercriminals behind the Locky ransomware attacks are upping their game by using an application linking feature in Windows to hit even more victims without being immediately noticed.

According to an advisory from the Internet Storm Center, the new variant of Locky ransomware exploits Microsoft’s Dynamic Data Exchange (DDE), a Windows feature that facilitates the electronic transfer of Office files using shared memory and data.

Locky Adopts DDE Hijacking Tactics

In keeping with similar approaches, the fraudsters created phony invoices laden with malicious links and distributed them via the Necurs spambot. Because they used DDE, the threat actors did not have to employ macros to download malware from a remote server.

The Locky malware self-destructs once the ransomware attacks are successful, at which point the cybercriminals demand payment in the form of bitcoin. Besides DDE, according to SecurityWeek, Locky is being disseminated via Visual Basic scripts and archived in formats such as RAR containing VBS, JSE and JS files. The variety of techniques makes the threat much more difficult for security experts to track.

DDE is hardly a new feature from Microsoft, dating back to the late 1980s. BankInfoSecurity pointed out that potential dangers associated with DDE include the ability for cybercriminals to instantly execute links in a document once a victim opens it.

Microsoft offered an alternative several years ago called Object Linking and Embedding (OLE) but continues to support DDE because it is a part of legacy versions of Office products. Though the company has been informed about the risks, it maintained that the issues with DDE do not technically represent a bug.

Predicting Locky Ransomware’s Next Move

Threatpost reported that the only way to avoid the issue entirely is to go into the settings of Office applications and ensure that they don’t automatically update links. Given that DDE is a legitimate feature, however, it is less likely to be stopped by traditional antivirus or security scanning systems.

Ransomware attacks from Locky will likely take many forms and target widely used applications such as Microsoft Word. Hijacking DDE may just be a taste of what’s yet to come.