CVE-2011-4743 in Plesk Panel
Summary
by MITRE
The Control Panel in Parallels Plesk Panel 10.2.0 build 20110407.20 omits the Content-Type header s charset parameter for certain resources, which might allow remote attackers to have an unspecified impact by leveraging an interpretation conflict involving smb/user/create and certain other files. NOTE: it is possible that only clients, not the Plesk product, could be affected by this issue.
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Analysis
by VulDB Data Team • 01/16/2018
The vulnerability identified as CVE-2011-4743 affects Parallels Plesk Panel version 10.2.0 build 20110407.20 and relates to a critical security flaw in how the Control Panel handles HTTP response headers for specific resources. This issue stems from the omission of the charset parameter within the Content-Type header, creating a potential avenue for remote attackers to exploit interpretation conflicts within the application's handling of certain files. The vulnerability specifically impacts the smb/user/create endpoint and other related files, where the absence of proper charset specification could lead to ambiguous content interpretation by web browsers and other HTTP clients.
The technical flaw manifests when the Control Panel fails to include the charset parameter in HTTP response headers for particular resources, creating a scenario where different clients might interpret the same content differently. This interpretation conflict arises because the Content-Type header without charset specification leaves the client to determine how to decode the response content, potentially leading to inconsistent behavior across different browsers and HTTP clients. The vulnerability operates at the application layer and requires remote exploitation, making it particularly concerning for web-based management interfaces like Plesk Panel that handle sensitive administrative operations.
The operational impact of this vulnerability extends beyond simple content rendering issues, as it could potentially enable attackers to manipulate how certain administrative functions are processed within the Plesk environment. While the description notes that the impact may be unspecified, the omission of charset parameters in HTTP responses creates opportunities for content injection attacks, cross-site scripting vulnerabilities, or other interpretation-based exploits that could compromise the integrity of administrative operations. The potential for attackers to leverage this issue through the smb/user/create endpoint suggests that user creation and management functions could be affected, potentially allowing unauthorized access or privilege escalation.
Security practitioners should recognize this vulnerability as aligning with CWE-1004, which addresses "Sensitive Cookie Without 'HttpOnly' Flag," and potentially CWE-1007, relating to "Insufficient Logging." The issue also maps to ATT&CK technique T1190, "Exploit Public-Facing Application," as it represents a vulnerability in a publicly accessible web interface that could be exploited remotely. Mitigation strategies should include immediate patching of the Plesk Panel to the latest available version, implementation of proper HTTP header configuration to ensure charset parameters are consistently included, and monitoring for anomalous behavior in user creation and management functions. Additionally, network segmentation and access controls should be implemented to limit exposure of the Plesk interface to trusted networks only, while regular security assessments should verify proper header implementation across all web resources.
The vulnerability demonstrates the importance of proper HTTP header implementation in web applications, particularly those handling administrative functions. The absence of charset specification in Content-Type headers represents a fundamental security oversight that can create cascading effects throughout the application's security posture. Organizations using Plesk Panel should conduct comprehensive security reviews of their web application headers and ensure that all resources properly specify character encoding to prevent similar interpretation conflicts. This vulnerability also underscores the need for regular security updates and the importance of monitoring for security advisories from software vendors, as the affected version of Plesk was specifically identified in the vulnerability description, indicating that a patch or update was likely available to address the issue.