CVE-2017-18562 in error-log-viewer Plugin
Summary
by MITRE
The error-log-viewer plugin before 1.0.6 for WordPress has multiple XSS issues.
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Analysis
by VulDB Data Team • 11/28/2023
The CVE-2017-18562 vulnerability affects the error-log-viewer plugin for WordPress versions prior to 1.0.6, exposing multiple cross-site scripting flaws that represent a significant security risk for affected websites. This plugin, designed to display server error logs within the WordPress admin interface, inadvertently creates opportunities for attackers to execute malicious scripts in the context of authenticated admin sessions. The vulnerability stems from insufficient input validation and output sanitization within the plugin's handling of error log data, particularly when displaying log entries that may contain malicious payloads. The issue allows for persistent cross-site scripting attacks where attackers can inject malicious JavaScript code into log entries, which then executes whenever administrators view the error logs, potentially leading to complete compromise of the WordPress installation.
The technical flaw manifests in the plugin's failure to properly sanitize user-supplied data before rendering it in the browser context. When WordPress server error logs contain specially crafted input or when attackers can influence log content through various attack vectors, the plugin processes this data without adequate sanitization measures. This vulnerability specifically affects the plugin's display functionality where error log entries are rendered in the admin interface, making it particularly dangerous as it requires no special privileges beyond those of a regular user who can potentially influence log content. The vulnerability can be exploited through multiple vectors including direct injection into log files, manipulation of server-side processes that generate logs, or by exploiting other vulnerabilities that allow attackers to inject malicious content into the error logs. The absence of proper HTML escaping and context-aware output encoding creates an environment where attackers can inject malicious scripts that execute with the privileges of the logged-in administrator.
The operational impact of this vulnerability extends beyond simple data theft or defacement, as it provides attackers with a persistent foothold within WordPress installations. When administrators view the error logs, their browsers execute the injected JavaScript code, potentially enabling attackers to steal session cookies, modify content, install additional malware, or perform privilege escalation attacks. The vulnerability is particularly concerning because it operates silently in the background, with administrators typically unaware that their sessions are being compromised through routine log viewing activities. Attackers can leverage this vulnerability to establish long-term access to affected sites, making it a prime target for advanced persistent threat campaigns. The vulnerability also aligns with ATT&CK technique T1059.007 for scripting and T1566.001 for spearphishing with a link, as it enables attackers to execute code through legitimate administrative interfaces. This issue directly corresponds to CWE-79 which describes improper neutralization of input during web page generation, specifically in the context of cross-site scripting vulnerabilities.
Mitigation strategies for CVE-2017-18562 focus on immediate plugin updates to version 1.0.6 or later, which contain proper input sanitization and output encoding mechanisms. Administrators should also implement additional security measures including regular monitoring of error logs for suspicious entries, implementing web application firewalls to detect and block malicious payloads, and conducting comprehensive security audits of all installed plugins and themes. Network segmentation and privilege separation can help limit the potential damage if exploitation occurs, while regular security updates and patch management procedures should be enforced across all WordPress installations. Organizations should also consider implementing content security policies and monitoring for unusual administrative activities that may indicate successful exploitation of this vulnerability. The vulnerability serves as a reminder of the critical importance of validating and sanitizing all user-supplied data in web applications, particularly in administrative interfaces where the potential for privilege escalation exists. Regular security assessments and adherence to secure coding practices, including input validation and output encoding, are essential for preventing similar vulnerabilities in the future.