PDF Phishing campaign uses Google Docs to steal victim's Email credentials

SonicWall Capture Labs Threats Research team has discovered an ongoing phishing campaign which abuses genuine web-based software office suite platform like google docs. Upon opening the PDF file, a blurred image with instructions on how to view the document is displayed to the user:

If the instructions as mentioned in the PDF file are followed, an HTML file is downloaded without user intervention from Google Docs URL as shown below:

When the downloaded HTML file is opened, the user is shown a genuine looking webpage with options to select email providers like Yahoo, Google, Outlook, Office etc to view the document:

Depending upon the email provider chosen by the user, one of the following form would be displayed:

Upon entering the user credentials and clicking the sign-in button the user is displayed a clean PDF file downloaded from remote server to appear legitimate:

However in the background the malware author steals user credentials when the sign-in button is clicked and sends them to remote web server “hxxps://webpersonaltrainer[.]top” as shown below:

These PDF files are not detected by any vendor when checked on top threat intelligence sharing portals like virus total:

SonicWall Capture Labs provides protection against this threat via the following signature:

• GAV: Downloader.FR (Trojan)
• GAV: Downloader.PD_18 (Trojan)

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The SonicWall Capture Labs Threat Research Team gathers, analyzes and vets cross-vector threat information from the SonicWall Capture Threat network, consisting of global devices and resources, including more than 1 million security sensors in nearly 200 countries and territories. The research team identifies, analyzes, and mitigates critical vulnerabilities and malware daily through in-depth research, which drives protection for all SonicWall customers. In addition to safeguarding networks globally, the research team supports the larger threat intelligence community by releasing weekly deep technical analyses of the most critical threats to small businesses, providing critical knowledge that defenders need to protect their networks.