CVE-2022-3334 in Easy WP SMTP Plugin
Summary
by MITRE • 10/31/2022
The Easy WP SMTP WordPress plugin before 1.5.0 unserialises the content of an imported file, which could lead to PHP object injection issue when an admin import (intentionally or not) a malicious file and a suitable gadget chain is present on the blog.
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Analysis
by VulDB Data Team • 05/07/2025
The Easy WP SMTP WordPress plugin vulnerability CVE-2022-3334 represents a critical security flaw that enables remote code execution through improper input validation and object deserialization. This vulnerability affects versions prior to 1.5.0 and stems from the plugin's insecure handling of imported configuration files. The flaw occurs when administrators import SMTP settings from external sources, creating an avenue for malicious actors to inject PHP objects that can be exploited to execute arbitrary code on the target system. The vulnerability aligns with CWE-502 which specifically addresses unsafe deserialization of untrusted data, making it a direct implementation of this well-known security weakness. The attack vector leverages the principle of object injection where malicious serialized data can trigger unintended behavior during the unserialization process.
The technical implementation of this vulnerability involves the plugin's import functionality processing user-supplied data without adequate sanitization or validation. When an administrator imports a configuration file, the plugin performs an unserialize operation on the imported content without sufficient security controls to prevent malicious object injection. This creates a scenario where attackers can craft specially formatted import files containing serialized PHP objects designed to exploit the application's runtime environment. The vulnerability becomes particularly dangerous when combined with existing gadget chains present in the WordPress environment, which are sequences of method calls that can be chained together to achieve arbitrary code execution. This pattern corresponds to ATT&CK technique T1505.003 for Server-side Template Injection and T1059.007 for Command and Scripting Interpreter, as the exploitation can lead to full system compromise.
The operational impact of CVE-2022-3334 extends beyond simple data theft or service disruption, potentially enabling complete system compromise and persistent access for attackers. An attacker who successfully exploits this vulnerability can execute arbitrary PHP code with the privileges of the web server, potentially leading to data exfiltration, lateral movement within the network, and establishment of backdoors. The risk is particularly elevated in environments where administrators frequently import external configuration files or where the plugin is used in conjunction with other vulnerable components. The vulnerability's severity is compounded by the fact that it requires minimal user interaction beyond the normal administrative import process, making it particularly stealthy and difficult to detect. The exploitation could result in complete takeover of the WordPress installation and subsequent compromise of the underlying server infrastructure.
Mitigation strategies for CVE-2022-3334 should focus on immediate plugin updates to version 1.5.0 or later, which includes proper input validation and sanitization of imported files. Administrators should implement strict file import policies, limiting the sources from which configuration files can be imported and ensuring that all imported files are properly validated before processing. The implementation of Content Security Policy headers and proper input sanitization controls can help prevent malicious object injection attempts. Additionally, organizations should conduct regular security audits of their WordPress installations, monitor for unusual import activities, and maintain up-to-date backups to facilitate rapid recovery in case of successful exploitation. Network segmentation and privilege separation can help limit the potential damage from successful exploitation, while regular security training for administrators can reduce the risk of accidental exposure through social engineering or misconfigured import processes.