WordPress-powered websites are being targeted in a comment spam campaign designed to get users to click on links to sites offering betting services on the 2018 FIFA World Cup games.
Security vendor Imperva recently observed a botnet spewing out meaningless text messages generated from a template to comments sections in blogs, news articles, and other sites that allow people to comment.
The spambot has been attempting to post comments to the same Uniform Resource Identifier (URI) across different WordPress sites indiscriminately and without regard for whether the site is vulnerable or even has a comments section.
The template that is being used to generate the messages has been around since at least 2013 and essentially gives spammers an automated way to craft slightly different versions of the same message. For example, one version of a message generated via the template might begin with ‘I have been surfing online more than 2 hours today, yet I never found an interesting article like yours’. Another version might say, ‘I have been browsing online more than three hours today, yet I never found an interesting article like yours.’
“Our analysis found that the top 10 links advertised by the botnet lead to World Cup betting sites,” Imperva said in its report on the campaign. “Interestingly, eight of the top advertised sites contained links to the same betting site, hinting that they might be connected in a way.”
The botnet itself is comprised of some 1,200 unique IPs, which by today’s measures is not especially large. In many cases that Imperva analyzed, the botnet has been using URL-shortening, URL redirection, and other techniques to try and hide the destination of advertised links in its spam messages.
In the weeks leading up to the World Cup, the botnet was being used in remote code execution attacks and other attacks on WordPress sites. But once the games started, the botnet’s main activity shifted to comment spam. This suggests that the botnet is available for hire and that the betting site being advertised via the current spam campaign are the ones paying for it, says Jonathan Azaria, security researcher at Imperva.
“Either the owners, or someone that benefits directly from the increased traffic via an affiliate program, for example,” looks to be behind the campaign he says.
Comment spam — like other forms of spam — has been around for a long time, but continues to be popular among threat actors because of how effective they are in delivering marketing messages or links to websites via comments on online forums.
WordPress itself has called comment spam a “fact of life” for anyone with a blog and has offered numerous tips and links on how to mitigate the issue.
The most common approaches have been to blacklist IPs sending spams messages and also the URLs that they advertise. Plug-ins are readily available for vetting comment submissions and ensuring comments and posts are not being generated by a spambot.
“Numerous solutions exist for comment spam,” Azaria says. “In some cases, a simple plugin will suffice. In others, a more complex solution is required such as a WAF, Captcha, [or a] bot detection and classification [tool],” he says.
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Jai Vijayan is a seasoned technology reporter with over 20 years of experience in IT trade journalism. He was most recently a Senior Editor at Computerworld, where he covered information security and data privacy issues for the publication. Over the course of his 20-year … View Full Bio