Researchers have found thousands of malicious web pages existing online that constitute a serious malware campaign. As observed, the hackers have set up 100,000+ of such websites delivering malware to the target users via malicious PDFs.
100,000 Websites Delivering Malware Via PDFs
Security researchers from cybersecurity firm eSentire have recently shared details of a new malware campaign in the wild.
Specifically, they have found over 100,000 different websites hosting malicious PDFs for delivering malware to the users. These websites basically aim at enterprise customers as they host PDFs related to business activities, such as templates, questionnaires, invoices, or receipts. The malicious websites also use these terms as keywords to bag higher ranking on SERPs.
How The Attack Works
In brief, the attack begins when a user lands at one of the malicious websites while searching for such documents. Upon clicking on the download option to get the PDF, the site redirects the user to another malicious web page. The latter then delivers a malicious executable disguised as a document file (PDF or Word) to the user.
This executable installs a RAT, identified as SolarMarker to the target device, bundled with the legit Slim PDF reader app, possibly, to bluff the target user.
SolarMarker RAT isn’t a new malware. Rather it had appeared numerous times in earlier campaigns as well, yet, with different names, such as Jupyter, Yellow Cockatoo, and Polazert.
Once established on the target device, the malware can then execute a variety of activities. As the researchers described in their post,
Once the RAT is on the victim’s computer and activated, the threat actors can send commands and upload additional malware to the infected system, such as ransomware, a credential stealer, a banking trojan, or simply use the RAT as a foothold into the victim’s network.
Detailed technical analysis of the malware campaign is present in the researchers’ post.
In an earlier campaign, Jupyter behaved as an info-stealer as well as a backdoor that could download other malware too.