Threat Management, Malware, Phishing

Malspam campaign fakes Google reCAPTCHA images to fool victims

A recently discovered malspam campaign targeting customers of a Polish bank was found using forgeries of Google reCAPTCHA images to fake legitimacy.

The banking malware was delivered via phishing emails that purported to seekin confirmation of a recent banking transaction that in reality never occurred, according to Feb. 21 blog post published week by Sucuri.

Recipients who panicked at the notion of an unauthorized transaction may have then clicked on a link leading to a malicious PHP file.

If the malicious file's code determines that the infected machine has user-agents associated with Google web crawler, then the user simply receives a fake 404 error page. All other infected machines are delivered a fraudulent Google reCAPTCHA page.

"This page does a decent job at replicating the look of Google’s reCAPTCHA, but since it relies on static elements, the images will always be the same unless the malicious PHP file’s coding is changed," explains the blog post, authored by Sucuri analyst Luke Leal.

At this point, the PHP code again checks user agent status to determine if the infected machine is Android-based. If so, it downloads a malicious .apk file that the attackers can use to intercept incoming SMS messages (including those used for two-factor authentication), as well as record audio. Non-Android devices are instead infected with a malicious .zip download.

Bradley Barth

As director of multimedia content strategy at CyberRisk Alliance, Bradley Barth develops content for online conferences, webcasts, podcasts video/multimedia projects — often serving as moderator or host. For nearly six years, he wrote and reported for SC Media as deputy editor and, before that, senior reporter. He was previously a program executive with the tech-focused PR firm Voxus. Past journalistic experience includes stints as business editor at Executive Technology, a staff writer at New York Sportscene and a freelance journalist covering travel and entertainment. In his spare time, Bradley also writes screenplays.

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