More than 2,000 WordPress sites have been infected with a malicious script that can deliver both a keylogger and the cryptocurrency miner CoinHive.

More than 2,000 sites running the WordPress CMS have been infected with a malicious script that can deliver both a keylogger and the in-browser cryptocurrency miner CoinHive.

This new hacking campaign was spotted by experts from the security firm Sucuri, the experts believe the attackers are the same that launched a campaign that infected 5,500 WordPress sites in December.

In both campaigns, the threat actors used a keylogger dubbed cloudflare[.]solutions, but be careful, there is no link to security firm Cloudflare.

After the discovery in December of campaign, the cloudflare[.]solutions domain was taken down, but this new discovery confirms that threat actors are still active and are using a new set of recently registers domains to host the malicious scripts that are injected into WordPress sites.

By querying the search engine PublicWWW, researchers discovered that the number of infected sites includes 129 from the domain cdns[.]ws and 103 websites for cdjs[.]online.

“A few days after our keylogger post was released on Dec 8th, 2017, the Cloudflare[.]solutions domain was taken down. This was not the end of the malware campaign, however; attackers immediately registered a number of new domains including cdjs[.]online on Dec 8th, cdns[.]ws on Dec 9th, and msdns[.]online on Dec 16th.” reads the analysis published by Sucuri.

“PublicWWW has already identified relatively few infected sites: 129 websites for cdns[.]ws and 103 websites for cdjs[.]online, but it’s likely that the majority of the websites have not been indexed yet. Since mid-December, msdns[.]online has infected over a thousand websites, though the majority are reinfections from sites that have already been compromised.”

Most of the infected domains are tied to msdns[.]online, with over a thousand reported infections. In many cases, threat actors re-infected WordPress sites compromised in the previous campaign.

The attackers target outdated and poorly configured WordPress sites, they inject the cdjs[.]online script either a WordPress database (wp_posts table) or into the theme’s functions.php file.

The Keylogger script is able to capture data entered on every website form, including the admin login form, information is sent back to the attackers via the WebSocket protocol.

Just like previous versions of the campaign leveraging a Fake GoogleAnalytics Script, researchers identified a fake googleanalytics.js that loads an obfuscated script used to load the malicious scripts “startGoogleAnalytics” from the attackers’ domains.

Experts discovered many similarities also in the cryptominer component of this campaign.

“We’ve identified that the library jquery-3.2.1.min.js is similar to the encrypted CoinHive cryptomining library from the previous version, loaded from hxxp:// 3117488091/lib/jquery-3.2.1.min.js?v=3.2.11 (or hxxp://185 .209 .23 .219/lib/jquery-3.2.1.min.js?v=3.2.11, a more familiar representation of the IP address). This is not surprising since cdjs[.]online also exists on the server 185 .209 .23 .219.” continues the analysis.

“It’s interesting to note that this script extends the CoinHive library and adds an alternative configuration using the 185 .209 .23 .219 server (and now specifically cdjs[.]online) for LIB_URL and WEBSOCKET_SHARDS.”

According to Sucuri experts, the threat actors behind this hacking campaign are active at least since April 2017. Sucuri has tracked at least other three different malicious scripts hosted on the same cloudflare.solutions domain across the months.

The first attack leveraging on these scripts was observed in April when hackers used a malicious JavaScript file to embed banner ads on hacked sites.

In November, experts from Sucuri reported the same attackers were loading malicious scripts disguised as fake jQuery and Google Analytics JavaScript files that were actually a copy of the Coinhive in-browser cryptocurrency miner. By November 22, the experts observed 1,833 sites compromised by the attackers.

Experts noticed that this campaign is still not massive as the one spotted in December, anyway it could not be underestimated.

“While these new attacks do not yet appear to be as massive as the original cloudflare[.]solutions campaign, the reinfection rate shows that there are still many sites that have failed to properly protect themselves after the original infection,” concluded Sucuri.

Pierluigi Paganini

(Security Affairs – WordPress sites, keylogger)

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