CVE-2017-18593 in UpdraftPlus Plugin
Summary
by MITRE
The updraftplus plugin before 1.13.5 for WordPress has XSS in rare cases where an attacker controls a string logged to a log file.
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Analysis
by VulDB Data Team • 12/07/2023
The vulnerability identified as CVE-2017-18593 affects the updraftplus WordPress plugin version 1.13.4 and earlier, representing a cross-site scripting flaw that emerges under specific conditions involving log file handling. This issue demonstrates how seemingly benign logging functionality can become a vector for malicious exploitation when proper input sanitization is lacking. The vulnerability specifically manifests when an attacker can influence content that gets written to log files, creating a scenario where malicious script execution becomes possible in the context of a user's browser session.
The technical implementation of this vulnerability stems from insufficient sanitization of user-controllable input within the plugin's logging mechanism. When the updraftplus plugin processes certain user inputs or system data, it writes this information to log files without adequate filtering or encoding of potentially malicious content. The flaw occurs during the logging process where strings containing user-supplied data are stored verbatim in log files, which are then later displayed in web interfaces without proper output encoding. This creates a classic XSS attack vector where malicious JavaScript code embedded within log entries can execute in the browser context of administrators or users who view these log files.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to escalate privileges and compromise entire WordPress installations. When administrators access log files through the WordPress admin interface or dedicated log viewing tools, any malicious scripts embedded in the log entries will execute in their browser context. This can lead to session hijacking, credential theft, or the execution of arbitrary commands on the compromised system. The vulnerability is particularly dangerous because it leverages legitimate administrative functionality to deliver malicious payloads, making detection more challenging and exploitation more effective.
The attack surface for this vulnerability is primarily limited to scenarios where attackers can influence input that gets logged, which may occur through various vectors including file uploads, plugin configuration changes, or user-submitted content that gets processed by the plugin. The vulnerability aligns with CWE-79 Cross-site Scripting, specifically categorized under the "Improper Neutralization of Input During Web Page Generation" weakness, and maps to ATT&CK technique T1059.007 Command and Scripting Interpreter: JavaScript. Organizations should implement comprehensive input validation and output encoding measures to prevent similar issues, as this vulnerability demonstrates how logging systems can become attack vectors when proper security controls are not implemented.
Mitigation strategies should focus on immediate plugin updates to version 1.13.5 or later, which contains the necessary fixes for this XSS vulnerability. Additionally, administrators should implement proper log file access controls, ensuring that only authorized personnel can view sensitive log information. Regular security audits of plugin code should include thorough reviews of logging mechanisms and input handling processes. The implementation of Content Security Policy headers can provide additional protection against XSS attacks by limiting script execution in web browsers. Organizations should also consider implementing automated monitoring for suspicious log file content and establish procedures for regular log file sanitization to prevent malicious content from persisting in system logs.