CVE-2011-4740 in Plesk Panel
Summary
by MITRE
The Control Panel in Parallels Plesk Panel 10.2.0 build 20110407.20 generates web pages containing external links in response to GET requests with query strings for smb/app/search-data/catalogId/marketplace 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 • 01/10/2018
The vulnerability identified as CVE-2011-4740 resides within the Control Panel component of Parallels Plesk Panel version 10.2.0 build 20110407.20, representing a significant security flaw that exposes sensitive information through improper handling of cross-domain referer headers. This issue manifests when the system processes GET requests containing specific query strings such as smb/app/search-data/catalogId/marketplace and related endpoints, creating web pages that inadvertently include external links in their responses. The fundamental technical flaw lies in the system's failure to properly sanitize or filter referer information before incorporating it into generated web content, creating a pathway for information disclosure through log analysis.
The operational impact of this vulnerability extends beyond simple information leakage, as it creates opportunities for attackers to harvest sensitive data from web server logs through two primary vectors. The first vector involves direct examination of web-server access logs where the external links containing referer information become visible to unauthorized parties. The second vector exploits web-server Referer logs which specifically track the origin of requests, allowing attackers to reconstruct user navigation patterns and potentially identify sensitive business or personal information. This cross-domain referer leakage vulnerability aligns with CWE-200, which addresses information exposure through improper information hiding, and represents a classic example of how seemingly innocuous logging mechanisms can become security risks when not properly secured.
The security implications of this vulnerability are particularly concerning given that it operates at the application layer and requires no authentication to exploit, making it accessible to any remote attacker with knowledge of the affected endpoints. Attackers can leverage this flaw to perform reconnaissance activities by analyzing log files to identify potentially sensitive user activities, system configurations, or business processes that may be exposed through the referer headers. This vulnerability also demonstrates characteristics consistent with ATT&CK technique T1083, which involves discovering system information through log analysis, and T1071, which covers application layer protocols and communication channels. The flaw essentially creates a covert channel through which sensitive information can be extracted without direct system compromise, making it particularly dangerous for environments where log files are accessible to unauthorized parties or where log retention policies are not properly enforced.
Mitigation strategies for this vulnerability should focus on implementing proper referer header sanitization and filtering within the Plesk Control Panel, ensuring that external links are not generated from query parameters that could contain sensitive information. System administrators should also implement robust log management practices, including access controls on log files, regular log rotation with appropriate retention policies, and monitoring for unusual referer patterns. Additionally, network-level firewalls and web application firewalls should be configured to filter out suspicious referer headers and monitor for patterns consistent with this type of information leakage. The most effective long-term solution involves updating to a patched version of Parallels Plesk Panel where the referer handling has been properly addressed, as the vulnerability represents a design flaw that cannot be adequately mitigated through configuration changes alone. Organizations should also conduct regular security assessments to identify similar cross-domain information leakage vulnerabilities in other applications and systems, as this type of flaw is not unique to Plesk and can occur in various web applications that improperly handle referer headers.