CVE-2011-4754 in Plesk Small Business Panel
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in Parallels Plesk Small Business Panel 10.2.0 allow remote attackers to inject arbitrary web script or HTML via crafted input to a PHP script, as demonstrated by smb/app/available/id/apscatalog/ and certain other files.
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Analysis
by VulDB Data Team • 01/26/2018
The vulnerability identified as CVE-2011-4754 represents a critical cross-site scripting flaw within Parallels Plesk Small Business Panel version 10.2.0, exposing organizations to significant web application security risks. This vulnerability resides in the web interface of the Plesk control panel, specifically affecting PHP scripts that process user input without proper sanitization mechanisms. The flaw allows remote attackers to inject malicious web scripts or HTML code into the application's response, potentially compromising user sessions and enabling unauthorized access to sensitive system information. The vulnerability is particularly concerning because it affects multiple endpoints within the application's architecture, with specific exploitation demonstrated against the smb/app/available/id/apscatalog/ path, though similar vulnerabilities exist in other files within the same application framework.
The technical implementation of this XSS vulnerability stems from insufficient input validation and output encoding within the Plesk control panel's PHP scripts. When users submit data through various web forms or API endpoints, the application fails to properly sanitize or escape the input before incorporating it into dynamic web responses. This lack of proper input sanitization creates an environment where attacker-controlled data can be executed as client-side scripts within the context of legitimate user sessions. The vulnerability manifests as reflected XSS, where malicious payloads are injected into the application's response and executed by the victim's browser when they view the affected page. This type of vulnerability is classified under CWE-79 as "Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')", which represents one of the most common and dangerous web application security flaws.
The operational impact of this vulnerability extends beyond simple script injection, potentially enabling attackers to escalate privileges, steal session cookies, perform unauthorized administrative actions, or redirect users to malicious websites. An attacker who successfully exploits this vulnerability could gain access to customer data, manipulate web hosting configurations, or establish persistent access to the compromised Plesk installation. The attack surface is particularly wide given that the vulnerability affects multiple files within the application's architecture, suggesting a systemic issue with input handling rather than isolated code flaws. This vulnerability aligns with ATT&CK technique T1566.001, "Phishing: Spearphishing Attachment", as attackers could leverage the XSS to deliver malicious payloads through compromised web interfaces, and T1071.001, "Application Layer Protocol: Web Protocols", since the exploitation occurs through standard web application protocols.
Organizations affected by this vulnerability should implement immediate mitigations including input validation and output encoding measures, though the most effective long-term solution involves upgrading to a patched version of Parallels Plesk Small Business Panel. The vulnerability demonstrates the critical importance of proper input sanitization in web applications and aligns with security best practices outlined in OWASP Top Ten 2017, specifically category A03:2017, "Injection", which includes XSS as a primary concern. Network segmentation, web application firewalls, and regular security assessments should be implemented as additional protective measures. The vulnerability also highlights the need for comprehensive security testing during software development cycles, as the flaw represents a failure in the application's defense-in-depth mechanisms. Organizations should conduct thorough vulnerability assessments of their Plesk installations and ensure all related components are updated to versions that address this specific XSS vulnerability.