CVE-2018-5213 in Simple Download Monitor Plugin
Summary
by MITRE
The Simple Download Monitor plugin before 3.5.4 for WordPress has XSS via the sdm_upload (aka Downloadable File) parameter in an edit action to wp-admin/post.php.
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Analysis
by VulDB Data Team • 01/20/2023
The CVE-2018-5213 vulnerability represents a cross-site scripting flaw in the Simple Download Monitor WordPress plugin affecting versions prior to 3.5.4. This vulnerability specifically targets the plugin's handling of user input within the administrative interface, creating a potential vector for malicious actors to execute arbitrary scripts in the context of authenticated administrator sessions. The flaw exists in the way the plugin processes the sdm_upload parameter during post editing operations through the wp-admin/post.php endpoint, which allows attackers to inject malicious JavaScript code into the plugin's administrative interface.
The technical implementation of this vulnerability stems from insufficient input validation and output sanitization within the plugin's backend processing logic. When administrators navigate to edit posts containing downloadable files managed by the Simple Download Monitor plugin, the sdm_upload parameter is not properly escaped or validated before being rendered in the HTML output. This failure in input sanitization creates a classic XSS attack surface where malicious payloads can be executed when administrators view the affected pages. The vulnerability specifically affects the edit action context within WordPress's administrative dashboard, making it particularly dangerous as it targets privileged users with elevated system access.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with the capability to escalate privileges and potentially compromise the entire WordPress installation. An attacker who successfully exploits this vulnerability could inject malicious scripts that steal administrator cookies, redirect users to malicious sites, or even modify plugin settings to persistently maintain access. The attack requires minimal privileges since it targets the administrative interface, meaning that even a user with limited permissions could potentially exploit this vulnerability if they can manipulate posts containing downloadable files. This creates a significant risk for WordPress sites where multiple users have editing capabilities, as the vulnerability could be triggered through content management workflows.
The vulnerability aligns with CWE-79 Cross-site Scripting, which classifies the flaw as a failure to properly sanitize user input before rendering it in web pages. From an ATT&CK framework perspective, this vulnerability maps to T1059 Command and Scripting Interpreter and T1190 Exploit Public-Facing Application, as it represents an exploitation of a web application vulnerability to execute malicious code. The attack vector specifically involves manipulating administrative workflows through the WordPress post editing interface, which falls under the category of privilege escalation through web application exploitation. Organizations should immediately update to Simple Download Monitor version 3.5.4 or later, as this release includes proper input sanitization and output escaping mechanisms that prevent the injection of malicious scripts.
Mitigation strategies should include immediate plugin updates combined with monitoring for suspicious administrative activity and user behavior patterns. Security administrators should implement network-based intrusion detection systems to monitor for potential exploitation attempts and establish regular security audits of WordPress plugin installations. Additional defensive measures include restricting administrative access through multi-factor authentication, implementing content security policies to prevent script execution, and conducting regular vulnerability assessments of all installed plugins to identify similar security flaws. The vulnerability demonstrates the critical importance of input validation in web applications and highlights how seemingly minor security oversights in plugin development can create significant risks for entire WordPress installations.