CVE-2023-0539 in GS Insever Portfolio Plugin
Summary
by MITRE • 02/27/2023
The GS Insever Portfolio WordPress plugin before 1.4.5 does not validate and escape some of its shortcode attributes before outputting them back in a page/post where the shortcode is embed, which could allow users with the contributor role and above to perform Stored Cross-Site Scripting attacks.
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Analysis
by VulDB Data Team • 03/25/2023
The vulnerability identified as CVE-2023-0539 affects the GS Insever Portfolio WordPress plugin version 1.4.4 and earlier, presenting a significant security risk through stored cross-site scripting exploits. This issue stems from inadequate input validation and output escaping mechanisms within the plugin's shortcode implementation, creating a persistent vector for malicious code injection that can affect users with contributor level privileges and higher.
The technical flaw manifests in the plugin's failure to properly sanitize shortcode attributes before rendering them in web pages where the shortcode is embedded. When administrators or contributors with appropriate permissions create or modify content using these shortcodes, the plugin processes user-supplied data without sufficient validation or escaping measures. This oversight allows attackers to inject malicious JavaScript code through shortcode parameters, which then gets stored within the WordPress database and executed whenever the affected page is loaded by other users.
The operational impact of this vulnerability extends beyond simple XSS attacks, as it provides attackers with a persistent foothold within the WordPress environment. Since contributors and above can execute these attacks, the vulnerability can be exploited by users who already have partial administrative privileges, potentially enabling more severe attacks such as session hijacking, data exfiltration, or privilege escalation. The stored nature of the vulnerability means that malicious scripts remain active until manually removed from the database, creating a long-term security risk for affected installations.
This vulnerability aligns with CWE-79, which specifically addresses Cross-Site Scripting flaws in web applications, and represents a classic case of insufficient output escaping in web applications. The attack vector follows patterns described in the MITRE ATT&CK framework under T1566, specifically the technique of "Phishing with Social Engineering", where attackers leverage trusted web applications to deliver malicious payloads to unsuspecting users. The exploitation requires minimal privileges and can be automated, making it particularly dangerous in multi-user WordPress environments where various roles may have access to shortcode functionality.
Mitigation strategies should prioritize immediate plugin updates to version 1.4.5 or later, which includes proper input validation and output escaping measures. Administrators should also implement additional security measures such as restricting contributor roles from accessing shortcode creation interfaces where possible, implementing content security policies to limit script execution, and monitoring for suspicious shortcode usage patterns. Regular security audits of installed plugins and themes remain essential for identifying similar vulnerabilities, while user role restrictions and privilege management should be reviewed to minimize potential attack surfaces. The vulnerability demonstrates the critical importance of proper input validation and output escaping in web applications, particularly in content management systems where user-generated content processing is common.