Researchers at WordFence have eyed a recent uptick in attacks on WordPress involving WP-VCD backdoor malware. Since August 2019, no other WordPress-targeting malware has yielded a higher rate of new infections that WP-VCD, the company reported this week in a blog post and in-depth white paper.
Such findings suggest that the malware, whose main purpose is to enable black hat SEO and malvertising activity, continues to pay off for attackers since it was first reported in the wild as far back as February 2017.
Website developers and administrators who use WordPress are typically infected with WP-VCD upon downloading malicious plugins or themes from unofficial third-party sites, states the Wordfence report, authored by Mikey Veenstra. Thanks to the attackers’ mastery of SEO, these pirated or “nulled” software programs can often be found on websites with high Google search term rankings, making them seem credible.
Once activated, the malware executes a deployer script that compromises the site by injecting backdoors into already installed themes, the report continues. Sneakily, this deployer eventually removes its own code from the malicious theme or plugin to hide evidence of the crime.