CVE-2011-4777 in Plesk Panel
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the Site Editor (aka SiteBuilder) feature in Parallels Plesk Panel 10.4.4_build20111103.18 allows remote attackers to inject arbitrary web script or HTML via the login parameter to preferences.html.
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Analysis
by VulDB Data Team • 01/13/2018
The vulnerability identified as CVE-2011-4777 represents a critical cross-site scripting flaw within the Site Editor component of Parallels Plesk Panel version 10.4.4_build20111103.18. This security weakness resides in the preferences.html interface where the login parameter fails to properly sanitize user input, creating an avenue for malicious actors to execute unauthorized web scripts or HTML code within the context of authenticated user sessions. The vulnerability specifically affects the Site Builder feature which is integral to the panel's web content management capabilities, making it a significant concern for administrators managing multiple client websites through this platform.
The technical exploitation of this XSS vulnerability occurs when remote attackers manipulate the login parameter in the preferences.html endpoint to inject malicious payloads. This flaw allows attackers to bypass standard input validation mechanisms that should normally prevent harmful code execution. The vulnerability manifests as a classic reflected XSS attack where malicious scripts are injected into the application's response and subsequently executed in the victim's browser when they navigate to the affected page. The attack vector specifically targets the authentication and preference management interface, potentially enabling attackers to hijack user sessions or perform actions on behalf of authenticated users.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable sophisticated attacks including session hijacking, credential theft, and unauthorized access to sensitive administrative functions. An attacker could craft malicious links that, when clicked by an authenticated user, would execute scripts to steal session cookies or redirect users to malicious sites. This vulnerability undermines the integrity of the Plesk Panel's authentication system and could potentially allow attackers to escalate privileges within the hosting environment. The implications are particularly severe for hosting providers who rely on Plesk for managing client accounts, as a compromised user session could provide access to multiple websites and customer data.
Mitigation strategies for CVE-2011-4777 should prioritize immediate patch application from Parallels, as this vulnerability was addressed in subsequent releases of the Plesk Panel software. Organizations should implement input validation and output encoding measures to prevent unauthorized script execution, with specific attention to sanitizing all user-supplied data in the login parameter field. Network-level protections such as web application firewalls can provide additional defense-in-depth measures, though they should not replace proper code-level fixes. The vulnerability aligns with CWE-79 which catalogs cross-site scripting weaknesses, and corresponds to ATT&CK technique T1566 related to spearphishing with malicious attachments or links, emphasizing the need for comprehensive security controls. Regular security assessments and input validation testing should be implemented to prevent similar vulnerabilities in other components of the hosting infrastructure.