CVE-2022-1559 in Clipr Plugin
Summary
by MITRE • 05/16/2022
The Clipr WordPress plugin through 1.2.3 does not sanitise and escape its API Key settings before outputting it in an attribute, leading to a Stored Cross-Site Scripting issue even when the unfiltered_html capability is disallowed
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Analysis
by VulDB Data Team • 05/18/2022
The CVE-2022-1559 vulnerability affects the Clipr WordPress plugin version 1.2.3 and earlier, presenting a critical stored cross-site scripting weakness that undermines web application security. This flaw resides in the plugin's handling of API Key settings where insufficient sanitization and escaping mechanisms allow malicious script code to be persistently stored and subsequently executed within the browser context of authenticated users. The vulnerability specifically manifests when the plugin outputs API Key values in HTML attributes without proper input validation, creating an attack surface that bypasses WordPress's default security measures including the unfiltered_html capability restriction that typically prevents script execution in user-generated content.
The technical exploitation of this vulnerability occurs through the manipulation of the plugin's settings interface where administrators or users with sufficient privileges can input malicious JavaScript code into the API Key field. When this data is later rendered in the plugin's administrative interface or frontend pages, the stored script executes within the context of the victim's browser session, potentially enabling attackers to perform actions on behalf of users with elevated privileges. This stored XSS vulnerability operates independently of the unfiltered_html capability restriction because the malicious code is embedded in HTML attributes rather than in content areas that would normally be filtered, making it particularly insidious as it can persist across multiple page loads and user sessions.
The operational impact of CVE-2022-1559 extends beyond simple script execution, as it can facilitate more sophisticated attacks including session hijacking, privilege escalation, and data exfiltration from compromised WordPress installations. Attackers can leverage this vulnerability to steal administrator credentials, modify website content, install malware, or redirect users to malicious sites, all while remaining undetected within the legitimate plugin interface. The vulnerability's persistence stems from the stored nature of the XSS payload, meaning that any user who views the affected plugin settings page becomes a potential victim without requiring repeated exploitation attempts. This characteristic aligns with CWE-79 which categorizes cross-site scripting vulnerabilities as weaknesses in input validation and output encoding, while the persistent nature of the flaw maps to ATT&CK technique T1566.001 for the initial compromise phase.
Mitigation strategies for this vulnerability require immediate plugin updates to versions that properly sanitize and escape API Key values before outputting them in HTML attributes. System administrators should also implement additional security measures including regular security audits of installed plugins, monitoring for unusual plugin behavior, and enforcing strict input validation policies. The remediation process must ensure that all user-supplied data is properly escaped using WordPress's built-in escaping functions such as esc_attr() or esc_html() when rendering plugin settings, and that API Key values are treated as sensitive data requiring special handling. Organizations should also consider implementing web application firewalls and content security policies to provide additional layers of protection against similar vulnerabilities, while conducting comprehensive vulnerability assessments to identify other plugins or themes that may exhibit similar sanitization flaws.