CVE-2011-4852 in Plesk Panel
Summary
by MITRE
The Control Panel in Parallels Plesk Panel 10.4.4_build20111103.18 generates web pages containing external links in response to GET requests with query strings for enterprise/mobile-monitor/ and certain other files, which makes it easier for remote attackers to obtain sensitive information by reading (1) web-server access logs or (2) web-server Referer logs, related to a "cross-domain Referer leakage" issue.
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Analysis
by VulDB Data Team • 01/26/2018
The vulnerability identified as CVE-2011-4852 resides within the Control Panel component of Parallels Plesk Panel version 10.4.4_build20111103.18, representing a significant security flaw that enables unauthorized information disclosure through cross-domain Referer leakage mechanisms. This issue specifically manifests when the system processes GET requests containing query strings targeting enterprise/mobile-monitor/ paths and similar endpoints, creating a scenario where sensitive data becomes inadvertently exposed through web server logging mechanisms. The vulnerability operates at the application layer, leveraging the inherent behavior of web browsers to transmit Referer headers containing full URLs when navigating between domains, thereby creating an information disclosure vector that can be exploited by remote attackers without requiring privileged access or complex attack vectors.
The technical implementation of this vulnerability stems from the Control Panel's improper handling of external links within generated web pages, particularly when these pages are constructed in response to specific query parameters. When legitimate users or automated systems access certain endpoints within the mobile-monitor/ path, the system generates HTML content that includes external links pointing to third-party domains. These links, when processed by web browsers, automatically append Referer headers containing the complete URL path that initiated the request, including any sensitive parameters or session identifiers that may have been part of the original query string. The flaw becomes particularly dangerous because it occurs in the context of web server logging, where access logs and Referer logs are commonly maintained for administrative purposes, system monitoring, and security auditing.
The operational impact of this vulnerability extends beyond simple information disclosure, creating potential risks for organizations managing sensitive data through the Plesk platform. Attackers can exploit this weakness by crafting malicious requests that, when processed by the vulnerable system, result in sensitive information being logged in web server access logs or Referer logs. This leakage can potentially expose session identifiers, user credentials, configuration details, or other sensitive parameters that were part of the original request, allowing unauthorized parties to reconstruct user sessions or gain insights into system configurations. The vulnerability is particularly concerning because it does not require authentication or direct system access, making it an attractive target for reconnaissance and information gathering activities that can precede more sophisticated attacks.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and sanitization within the Control Panel's response handling mechanisms. Organizations should consider disabling or restricting access to the vulnerable enterprise/mobile-monitor/ endpoints when such access is not required for legitimate business operations. The implementation of web application firewalls or security headers that limit Referer header transmission can help reduce the exposure, while regular monitoring of web server logs should include checks for suspicious patterns that may indicate exploitation attempts. Additionally, system administrators should ensure that access logs and Referer logs are properly secured and that sensitive information is not inadvertently exposed through logging mechanisms, following the principle of least privilege and implementing proper log management practices that align with security frameworks such as those outlined in the CWE classification system.
The vulnerability aligns with several ATT&CK framework techniques including T1083 (File and Directory Discovery) and T1566 (Phishing), as it enables attackers to gather information that can be used for further exploitation or social engineering attacks. It also relates to the CWE-200 vulnerability category, which covers "Information Exposure," specifically addressing cross-domain Referer leakage as a method of information disclosure. Organizations should consider this vulnerability as part of a broader security assessment, particularly when evaluating their web application security posture and implementing defense-in-depth strategies that address multiple attack vectors simultaneously. The remediation approach should include not only immediate patching of the affected Plesk version but also long-term security architecture improvements that prevent similar issues from occurring in other components of the system.