CVE-2022-28221 in CleanTalk AntiSpam Plugin
Summary
by MITRE • 04/20/2022
The CleanTalk AntiSpam plugin
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Analysis
by VulDB Data Team • 04/27/2022
The CleanTalk AntiSpam plugin for WordPress presents a critical security vulnerability that allows authenticated attackers with contributor-level permissions or higher to execute arbitrary code on affected systems. This vulnerability stems from insufficient input validation and sanitization within the plugin's handling of user-supplied data, creating a path for remote code execution attacks that can compromise the entire WordPress installation. The flaw exists in the plugin's administrative interface where user inputs are not properly validated before being processed, enabling attackers to inject malicious payloads that get executed with the privileges of the affected WordPress user account.
The technical implementation of this vulnerability involves a classic command injection flaw where attacker-controlled data flows directly into system execution contexts without proper sanitization. When administrators or users with sufficient privileges access certain plugin interfaces, the vulnerable code processes user inputs through functions that do not adequately filter or escape special characters that could be interpreted as shell commands. This behavior aligns with CWE-77 and CWE-94 categories, representing command injection and code injection vulnerabilities respectively. The attack surface is particularly concerning as it requires only contributor-level access, making it accessible to users who should normally have limited administrative capabilities within WordPress environments.
The operational impact of this vulnerability extends beyond simple code execution to encompass complete system compromise and potential data breaches. An attacker who successfully exploits this vulnerability can gain access to sensitive user data, modify content, install additional malware, or establish persistent backdoors within the WordPress environment. The vulnerability affects WordPress installations running the CleanTalk AntiSpam plugin version 6.105 and earlier, with the attack vector being particularly dangerous in multi-user environments where contributors or authors might have unexpected access levels. This weakness creates a significant risk for websites that rely on the plugin for spam protection while potentially exposing critical system resources to unauthorized access.
Security mitigations for this vulnerability should focus on immediate plugin updates to version 6.106 or later, which contain patches addressing the input validation issues. Organizations should also implement network segmentation and access controls to limit the potential impact of successful exploitation attempts. Regular security audits of installed plugins and themes should be conducted to identify similar vulnerabilities in other third-party components. The remediation process must include thorough testing of updated plugins in staging environments before deployment to production systems. Additionally, implementing web application firewalls and monitoring for suspicious administrative activities can help detect exploitation attempts. This vulnerability demonstrates the importance of proper input validation and the principle of least privilege in web application security, aligning with ATT&CK technique T1059 for command and script injection and T1078 for valid accounts as part of broader defensive strategies.