Avada theme – the most popular theme in WordPress – is the top-selling theme in ThemeForest, selling over 900,000 copies. The theme is paired with an Avada Builder plugin, developed by ThemeFusion.
This theme calls itself "The Complete WordPress Website Building Toolkit," and is geared for premium website builders. Without ever writing a single line of code, it can create everything from one-page business websites to an online marketplace.
Among the many vulnerabilities exhibited in the Avada Builder plugin, the first is the Authentic SQL Injection(CVE-2023-39309). By exploiting this flaw, the threat actors may enable authentication access, followed by compromising sensitive data and may execute remote code.
The second vulnerability, named ‘Reflected Cross-Site Scripting (XSS)’ vulnerability (identified as CVE-2023-39306) enables unauthenticated attackers to steal sensitive data and perhaps elevate their privileges on affected WordPress sites.
Additionally, Patchstack found a number of flaws in the Avada theme. A Contributor+ Arbitrary File Upload vulnerability (CVE-2023-39307) is the first among them. In this case, Contributors are given the authority to upload whatever file they choose, including potentially harmful PHP scripts, allowing remote code execution and jeopardizing the integrity of the site.
The discovery of a similar Author+ bug (CVE-2023-39312) is also significant. Here, Authors are given the option to post malicious zip files, potentially introducing the website as susceptible to vulnerabilities and remote code execution.
Also, this series of vulnerabilities include the Contributor+ Server-Side Request Forgery (SSRF) vulnerability (CVE-2023-39313). This flaw allows Contributors to send requests to internal WordPress services, which could lead to illegal actions or data access within the organizational structure.
The vulnerabilities were first discovered and reported to the Avada vendor on July 6, 2023, following which patched versions were made available on July 11. The security alert was made public on August 10, 2023, and Patchstack added the flaws to their database of vulnerabilities.
In order to address the flaws, users are advised to update their Avada Builder plugin to version 3.11.2 and the Avada theme to version 7.11.2, ensuring website security.
As reported by the Threat Intelligence team at Wordfence, reports of threat actors attempting to exploit the two issues in ongoing attacks had appeared as of May 6.
Elementor Pro is a paid plugin with an estimated number of over 1 million active installs, enabling users to quickly and easily develop WordPress websites from scratch, with the aid of a built-in theme builder, a visual form widget designer, and custom CSS support.
The Elementor Pro vulnerability is an RCE (Remote Code Execution) bug rated as Critical. It enables attackers with registered user access to upload arbitrary files to the affected websites and remotely execute code.
In order to preserve access to the compromised sites, attackers who successfully exploit this security issue can either install backdoors or webshells, obtain full admin access to completely compromise the site, or even entirely eliminate the site.
In case they are unable to register as users, they can exploit the second vulnerability in the over 110,000-site-installed Ultimate Addons for Elementor WordPress plugin, which will let them sign up as subscriber-level users on any site using the plugin even if user registration is disabled.
"Then they proceed to use the newly registered accounts to exploit the Elementor Pro [..] vulnerability and achieve remote code execution," as Wordfence discovered.
In order to protect oneself from the ongoing attacks, it is advised to update your Elementor Pro to version 2.9.4, that patches the remote code execution vulnerability.
Users of the Ultimate Addons for Elementor will have to upgrade to version 1.24.2 or later. To be sure that your website has not already been compromised, Wordfence advises taking the following actions:
According to a study conducted by Sucuri, the campaign, which it named "Balada Injector," is prolific and Methuselah-like in its endurance, infecting victim sites with malware at least since 2017. After being injected into the page, the malicious code leads users to a variety of scam websites, such as those offering fake tech support, bogus lottery wins, and push notifications requesting Captcha solutions.
However, behind the scenes, injected scripts look for numerous files, including access logs, error logs, debug information files, database management tools, administrator credentials, and more, that might include any sensitive or potentially helpful information. In addition, backdoors are loaded into the websites for enduring access and, occasionally, site takeover.
While the 1 million statistic represents the total number of sites that have been infected over the past five years, researchers only recently linked all the activities into a single operation. The campaign is still going strong and does not appear to be slowing down.
Sucuri researchers were able to link all of the observed activity to the Balada Injector campaign since it has a few easily distinguishable attributes. These include using a rotating roster of domain names where malicious scripts are placed on haphazard subdomains, uploading and leaving numerous backdoors all across the hacked environment, and spammy redirects.
Moreover, the developers of Balada Injector also exploit security flaws in WordPress plug-ins and themes, which is likely most noteworthy. These modular WordPress add-ons enable site administrators to integrate a variety of features, such as polling support, message board assistance, or click-to-call integration for e-commerce businesses.
"All sorts of vulnerabilities in WordPress themes and plugins can allow an attacker to inject code or gain unauthorized access to the website — which can eventually be escalated to the level where code injections are possible[…]This entire time, Balada Injector has been quickly adding newly disclosed vulnerabilities (and sometimes disclosed zero-days), occasionally starting massive waves of infections within a few hours after vulnerability disclosures," Sucuri analysis explains.
Sucuri has been tracking new waves of activity happening every couple of weeks, with lulls in between that are "probably utilised for gathering and testing newly reported and zero-day vulnerabilities."
Moreover, older vulnerabilities are also included in the mix, with some still in use by the campaign for months or years after being patched.
Given how the WordPress ecosystem is extremely buggy, it has become a popular target for cybercriminals among any other stripes.
"Depending on how you measure it, in 2023, WordPress still powers 60% of the websites available on the Internet today[…]The sheer volume of code that goes into this, the degree of customization often present on WordPress sites, and in general the WordPress plug-in ecosystem's complexity, popularity, and the lack of consistent security measures and practices, contribute to its attractiveness to cybercriminals as a rich hunting ground for exploitable bugs," says Casey Ellis, founder, and CTO at the Bugcrowd bug bounty platform.
To safeguard oneself against Balada Injector and other WordPress threats, companies must first ensure that all of their website software is updated, delete unused plug-ins and themes, and implement a Web application firewall to protect against Balada Injector and other WordPress threats.
According to Mike Parkin, senior technical engineer at Vulcan Cyber, the ease with which plug-ins can be added to WordPress from authorized download stores (much like the ecosystem for mobile apps) adds to the security issue. As a result, education for the Web team regarding the risks of installing unapproved modules is also necessary.
"The myriad available plug-ins, multiple places to get them, and the ease of deployment — you have a recipe for easy malicious plug-in distribution," he says.
Even large organizations are not resistant to WordPress Security problems. "There are cases, even in large enterprises, where a website is developed and maintained by an individual or small team[…]Often, those folks aren’t especially security conscious and are more interested in keeping their site up and fresh than they are in doing it securely. Patches get missed. Security alerts get missed. New and interesting plug-ins get installed without making sure they are safe or, sometimes, even work," he adds.