Rewterz Threat Alert – Data URLs and HTML Entities in New WordPress Malware

Severity

Medium

Analysis Summary

A WordPress malware campaign is leveraging various HTML features to obscure the scripts being injected into victim websites. Sucuri has published a blog post analyzing the different methods used in this campaign. In both versions of the campaign analyzed by researchers, the script executed on comprised websites redirects visitors to push notification scam sites. The first identified script abuses the data URL notation functionality of HTML. Using this method, the attackers can place their scripts inline with the data:text/javascript type in the src parameter instead of between source tags. This makes the script less detectable as it is not situated where most injected scripts usually are. In order to further obfuscate their script and decrease detection, the attackers evolved their campaign to additionally leverage HTML entities. The scripts are modified by replacing various characters with their entity names or numbers, which makes the content less readable and thus, less detectable. To inject this code into the sites, various vulnerabilities in WordPress themes and plugins are being exploited.

Impact

Exposure of sensitive information

Affected Vendors

WordPress

Remediation

• Block all threat indicators at your respective controls.
• Always be suspicious about emails sent by unknown senders.
• Never click on the links/attachments sent by unknown senders.