Winsage
May 4, 2025
Microsoft has warned about the increasing use of PDF attachments in cyberattacks, particularly during the U.S. tax season. Attackers have been using PDFs with embedded links that redirect users to counterfeit pages, such as a fake DocuSign site. TrustWave SpiderLabs has identified a new campaign involving a fake payment SWIFT copy that leads to a malicious PDF containing obfuscated JavaScript, which downloads a script that conceals the RemcosRAT payload using steganography. This technique involves hiding links within images, making them difficult to detect. The latest attacks begin with phishing emails containing malicious PDFs that direct victims to harmful webpages, facilitating the delivery of RemcosRAT, a trojan that allows remote control of compromised systems. Users are advised to be cautious of emails labeled “SWIFT Copy” and to delete suspicious emails immediately.
