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Executive Summary
This report outlines the critical risks associated with an unauthenticated arbitrary file upload vulnerability affecting the Security & Malware scan by CleanTalk plugin for WordPress. The vulnerability, denoted as CVE-2024-13365, impacts versions of the plugin up to and including 2.149 and has earned a maximum CVSS score of 10.0. Various sectors, including technology and government organizations in Eastern Europe and East Asia, consistently find themselves as favored targets for APT groups exploiting similar flaws. This vulnerability facilitates the remote, unauthenticated upload of files, potentially enabling malicious actors to deploy backdoors and execute arbitrary code on compromised servers.
Technical Information
The Security & Malware scan by CleanTalk plugin was designed to assist WordPress administrators in scanning for and mitigating malware and other security issues. Unfortunately, this very tool is now at the center of an alarming security concern. Vulnerability CVE-2024-13365 enables a remote attacker to upload any file without proper authentication, bypassing the inherent safeguards designed to prevent unauthorized command execution. In this instance, the vulnerability stems from an inadequate validation process for file uploads, which does not enforce strict checks on the type, content, or metadata of the files being transferred. As a result, an attacker can potentially upload executable scripts or backdoors that bypass traditional security systems, leading to an arbitrary code execution scenario that can fully compromise a WordPress site.
This technical issue demonstrates a serious security oversight. The root cause relates to a failure in utilizing secure file handling practices such as content-type validation and hardened file extension checks. The plugin does not correctly sanitize user inputs or uploaded file names, and its reliance on outdated methods for checking file integrity facilitates exploitation. Additionally, the vulnerability is particularly dangerous because it allows to bypass authentication mechanisms altogether, meaning that even highly secured sites with robust login procedures are at risk. The potential impact of this vulnerability is profound, as it directly undermines the baseline security assurance provided by the plugin, thereby opening the door to a wide array of malicious attacks, including the installation of remote access trojans, data exfiltration, and pivoting to other critical systems.
During an in-depth analysis, it was found that the flawed file upload mechanism does not perform server-side scanning or heuristic analysis at the time of file handling, which compounds the risk of exploitation. This design oversight permits files with embedded malicious code to remain unnoticed until they are executed, often triggered by legitimate system processes or user interaction. Furthermore, attackers can mask the malicious code within seemingly benign files, evading detection from many automated security measures implemented by default on WordPress installations. The wider implications of exploiting this vulnerability include unauthorized system control and complete server compromise, resulting in prolonged downtime and severe reputational damage for compromised organizations.
It is critical to note that the technical characteristics of CVE-2024-13365 superimpose on an already challenging threat landscape, where automated scanning tools by cybercriminals are constantly searching for vulnerable plugin installations. The arbitrary file upload capability provided by this vulnerability is not merely theoretical; it forms the basis for a concrete attack vector that enables threat actors to create persistent footholds in otherwise secure systems. In analytical tests and simulated exploit scenarios performed by security researchers, vulnerability scanning identified multiple stages of the exploitation chain, including the bypass of file-type filters, directory traversal techniques, and post-upload execution of hostile scripts. All these factors contribute to a highly exploitable vector that can result in massive operational disruptions.
This vulnerability shares numerous technical similarities with previous high-risk exposures such as vulnerabilities documented in WordPress Security Plugins and other content management system add-ons. It strongly parallels issues encountered in other notable file upload vulnerabilities where an initial arbitrary upload leads directly to remote code execution (RCE). The analysis of this vulnerability involves understanding not only the coding flaws but also the subsequent risk management protocols that can either exacerbate or mitigate the threat. Continuous updates and regular patching are paramount, given that exploitation could involve lateral movement within a network and subsequent escalation privileges, allowing attackers to traverse multiple systems.
Furthermore, the general complexity inherent in managing cybersecurity for widely-adopted platforms such as WordPress means that any single exploit can resonate across thousands of sites. The particular weakness in the plugin's file validation mechanism is compounded by the standard practices in many web hosting environments where file system permissions and execution policies are configured less stringently. As such, the vulnerability has the potential to become an active threat if discovered by malicious groups actively monitoring public vulnerability databases. Developers are urged to review their secure coding practices and deploy additional layers of server hardening to minimize the potential for similar vulnerabilities.
In response to these technical shortcomings, the developers of the Security & Malware scan by CleanTalk plugin have released version 2.150. This update addresses the core issues by introducing enhanced file type verification, improved sanitization routines, and reinforced server-side execution controls designed to prevent arbitrary file uploads. It is paramount for all users to promptly upgrade from any version up to 2.149 to mitigate the identified risk. Additionally, server administrators are advised to conduct a meticulous audit of their file system and monitor server logs regularly to identify any unusual activities associated with file uploads. Continuous vigilance, combined with the deployment of new security measures and improved logging protocols, will significantly reduce the window of exploitation.
Exploitation in the Wild
To date, there have been no widely reported incidents or proof-of-concept exploits in the wild that leverage CVE-2024-13365 for the Security & Malware scan by CleanTalk plugin. Nonetheless, security researchers have demonstrated through controlled environments how the vulnerability could be exploited to upload malicious scripts or backdoors. Specific usage scenarios involve the crafting of a payload that mimics legitimate file uploads, thus circumventing routine file type verifications. Indicators of compromise (IOCs) include anomalous log entries documenting unexpected file uploads, unusual file permissions changes, and the presence of executable scripts in directories not designated for such content. Organizations should remain alert to these subtle indicators and employ intrusion detection systems (IDS) and file integrity monitors that can alert system administrators to potentially harmful activities related to file upload anomalies.
In exploited scenarios, threat actors have been observed attempting to mask their activity by using common file extensions and embedding malicious code in otherwise benign file names. This requires that incident response teams double-check any unusual entries in their web server access logs and other monitoring systems against known file upload attempts. Additional IOCs may include unauthorized HTTP POST requests to script execution endpoints and unexpected outbound connections from compromised servers, indicating that the attacker is establishing command and control channels. It is essential for security teams to coordinate closely with their threat intelligence providers and subscribe to updates from the National Vulnerability Database and Patchstack Vulnerability Database for real-time indicators related to this vulnerability.
APT Groups using this vulnerability
Even though there is no confirmed exploitation of CVE-2024-13365 by advanced persistent threat groups in the wild, historical data reveals that similar vulnerabilities are quickly adopted by APT groups when they present minimal technical hurdles for exploitation. Groups operating out of Eastern Europe and East Asia have shown a predisposition for targeting vulnerable WordPress installations, particularly in the technology and governmental sectors. These groups have previously exploited arbitrary file upload vulnerabilities similar to the one affecting the Security & Malware scan by CleanTalk plugin to establish persistent access. Their modus operandi typically involves reconnaissance for minimally protected upload endpoints, deploying backdoors, and subsequently moving laterally within the victim network. Such groups are known for their precise targeting and extensive use of custom scripts and automation tools to identify and exploit vulnerable systems across several continents.
APT groups utilize an array of sophisticated tools such as those documented within the MITRE ATT&CK Framework where techniques like T1190 (Exploit Public-Facing Application) and T1059 (Command and Scripting Interpreter) are common. The sophistication of these groups means that once an initial foothold is established, they rely on stealth and persistence, often compromising multiple interconnected systems before detection. A considerable number of these threat actors have been observed targeting organizations in sectors where high-stakes data and intellectual property are at risk; therefore, organizations operating in these environments should prioritize rapid remediation and continuous monitoring in their risk management strategies.
Affected Product Versions
The affected product in this report, Security & Malware scan by CleanTalk plugin for WordPress, includes all versions up to and including version 2.149. Users running these versions are susceptible to the unauthenticated arbitrary file upload flaw detailed under CVE-2024-13365. The vulnerable software also involves configurations where the file upload process is not coupled with enhanced server-side input validation techniques, making exploitation more likely under common misconfigurations. Administrators who have not yet upgraded to version 2.150 of the plugin remain at high risk of malicious exploitation. It is essential that organizations conduct a thorough audit of their WordPress environments to confirm that no instances of the vulnerable versions persist, ensuring that all components of the system receive the necessary updates and patches to mitigate these risks.
Workaround and Mitigation
Immediate update procedures are critical for reducing exposure to this vulnerability. All users should ensure that they upgrade the Security & Malware scan by CleanTalk plugin to at least version 2.150, as this release incorporates fixes for the file upload validation issues that form the basis of CVE-2024-13365. In instances where an immediate update is not feasible, alternative protective measures such as implementing virtual patching solutions using tools like Patchstack can provide temporary mitigation. Organizations are advised to harden file permission settings on their web servers, restrict direct file uploads, and enforce strict monitoring of file system changes. Additionally, deploying intrusion detection systems that are capable of flagging abnormal file activity and anomalous HTTP POST requests is crucial. Regular reviews of server logs, coupled with file integrity monitoring, will help to detect early signs of exploitation and prompt a swift incident response, thereby minimizing potential lateral movement of attackers within the network.
References
Patchstack Vulnerability Database (https://patchstack.com/database/wordpress/plugin/security-malware-firewall/vulnerability/wordpress-security-malware-scan-by-cleantalk-plugin-2-149-unauthenticated-arbitrary-file-upload-vulnerability) and National Vulnerability Database (https://nvd.nist.gov/vuln/detail/CVE-2024-13365) provide verified insights into the technical details and historical context of this security issue. Additional information is available from research papers documenting arbitrary file upload vulnerabilities in content management systems and case studies on similar exploits in WordPress plugins. The MITRE ATT&CK Framework also offers detailed descriptions of related attack vectors and techniques, which further underscores the critical nature and potential exploitation paths of such vulnerabilities. Detailed technical documentation on file upload vulnerabilities and secure coding best practices in PHP-based applications can be found in specialized developer resources and cybersecurity research publications that are periodically updated by industry experts.
Rescana is here for you
Rescana supports its customers by providing a comprehensive Third Party Risk Management platform that streamlines the process of assessing and mitigating risks across your supply chain and digital ecosystem. Our platform equips organizations with the analytical tools to continuously monitor for vulnerabilities, manage remediation efforts, and ensure that their security posture adapts to emerging threats. For any additional questions about this report or any other issues, we are happy to provide further assistance. Please contact us via email at ops at rescana.com for expert guidance and support.