A malicious Google Chrome extension dubbed Catch-All is stealing data, potentially including credit card information, using a simple phishing ploy to lure victims, a security researcher warned.

According to the Internet Storm Center, the threat actors initiate the data theft scheme by sending out invitations to view photos on WhatsApp. If a user clicks on the link, he or she will download whatsapp.exe, a malware dropper file. This launches what looks like an Adobe PDF Reader, but those who install it wind up activating md1.exe and md0.exe, which are bundled in a .cab file.

As a result, Google Chrome processes and Windows Firewall shut down, at which point the Catch-All extension grabs any data the victim has posted online. It also uses jQuery AJAX connections to send it to a command-and-control (C&C) server.

Detailing the Data Theft

Catch-All gives fraudsters several opportunities to steal data, including usernames and passwords, Help Net Security reported. That’s a lot worse than similar threats, which tend to focus on offering up unwanted advertising, sending unsolicited emails or monitoring browser traffic.

Meanwhile, by using real URLs that run as normal instead of local proxies or bogus SSL certificates, traditional security services may not notice the data theft taking place, according to the Internet Storm Center report.

Threatpost reported that Catch-All may be primarily focused on Portuguese-speaking users based in Brazil, since that’s the language in which the phishing emails were composed. Even if they originated in Brazil, however, there’s no reason to expect the cybercriminals behind the data theft will limit themselves to that region.

A Catch-22 for Browser Extensions

As Hot For Security pointed out, Google Chrome extensions have been full of surprises lately, including a recent attempt to install a cryptocurrency mining application on users’ machines. Catch-All distinguishes itself from these peers by attempting to commit data theft that is as thorough and wide-ranging as possible.

Think about how much information a user keys into a browser during an average session. If its victims aren’t careful, Catch-All could wind up catching an awful lot.

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