Thousands of WordPress websites have been hijacked recently to redirect to a "work at home" scam, according to researchers at Zscaler ThreatLabz.
The WordPress sites were hijacked to redirect visitors to the sites to two scam URLs, Julian Sobrier, a senior security researcher at Zscaler, wrote on the ThreatLabz blog. It appears that the scammers had added new pages with randomly-generated filenames inside the /wp-includes/ directory on the sites.
Attackers like to put malicious pages inside standard directories such as /wp-includes/ because many users generally don't know which files belong there and which do not, Sobrier told SecurityWeek. The /wp-includes/ directory is a part of every WordPress installation and contains much of the core code. Webmasters recommended not adding, removing, or modifying files in this directory as it may cause the WordPress site to stop working.
"Attackers choose carefully the location of their new files to hide them," Sobrier said.
While some of the hijacked sites have been blacklisted by Google Safe Browsing, majority of them are not flagged, Sobrier said. The visitors to these WordPress sites are all redirected to one of the two scam sites, realonlineincnow.com or online13workhome.com. Neither site was blacklisted by Google Safe Browsing at the time Sobrier wrote the post.
These hijacked sites were legitimate WordPress sites which had been hacked specifically for the campaign, Sobrier said. The scammers appeared to be sending out spam to propagate the link to the hijacked Websites.
Even though work-from-home scams are not new, Sobrier felt this particular campaign was "one of the biggest campaigns" due to the number of hijacked Websites. This campaign just illustrates how compromising thousands of Websites to redirect traffic to a malicious site can be "very easy, and very cheap" to do, Sobrier said.
The malicious scam site almost always takes on the appearance of a media outlet, including legitimate ones such as NBC or made-up outlets with "newsy" names, with a news article touting the success of the particular "opportunity." It usually goes along the lines of how someone was able to make several thousand dollars a month from home. Most of them are also well-designed, with fake ads and links to news summaries.
"Work at home" scams have been around in some shape or form for a long time, and scammers are continuously finding new ways to target victims. Many of the sites take advantage of localization capabilities in order to modify the title of the article to reflect the site visitor's geographic location.
Earlier this year, many of the scam sites started displaying Facebook Like icons on their pages to convey a sense of legitimacy. Facebook allows you to embed any Like widget on any website, even if the domains or URLs do not correspond. Scammers are using this trick to appear more legitimate, by tricking visitors into thinking their website has been visited and liked by many people.
Zscaler researchers also found that several work from home sites appeared earlier this year on the list of the top-20,000 most visited sites in the world.