CVE-2017-10679 in Piwigo
Summary
by MITRE
Piwigo through 2.9.1 allows remote attackers to obtain sensitive information about the descriptive name of a permalink by examining the redirect URL that is returned in a request for the permalink ID number of a private album. The permalink ID numbers are easily guessed.
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Analysis
by VulDB Data Team • 12/09/2022
The vulnerability described in CVE-2017-10679 affects Piwigo versions through 2.9.1 and represents a significant information disclosure flaw that undermines the security of private album access controls. This vulnerability exists within the web application's handling of permalink requests for private albums, where the system inadvertently reveals sensitive metadata through redirect responses. The flaw specifically manifests when attackers make requests to permalink ID numbers associated with private albums, causing the application to return redirect URLs that contain information about the descriptive names of these permalinks. This occurs because the application's URL structure and access control mechanisms are improperly configured to prevent unauthorized disclosure of album metadata even when the underlying content remains protected.
The technical implementation of this vulnerability stems from predictable permalink ID generation patterns that allow attackers to systematically guess valid ID numbers for private albums. When a request is made to a specific permalink ID, the system responds with an HTTP redirect that includes the descriptive name of the permalink in the redirect URL, effectively leaking information about the album's purpose or content. This represents a classic case of information exposure through improper access control and insufficient input validation. The vulnerability operates at the application layer and can be exploited through simple reconnaissance techniques, as attackers can enumerate valid permalink IDs through systematic guessing or automated tools that exploit the predictable nature of the ID generation algorithm. The flaw directly violates security principles related to least privilege and defense in depth, as it provides unauthorized access to metadata that should remain confidential within a properly secured system.
The operational impact of this vulnerability extends beyond simple information disclosure, as it creates a pathway for attackers to gather intelligence about the content and structure of private photo collections. An attacker who can successfully exploit this vulnerability can build a comprehensive map of private album names and potentially identify sensitive content based on descriptive naming patterns. This information can then be used to plan more sophisticated attacks or to target specific content for further exploitation. The vulnerability is particularly concerning because it affects private albums, which by definition should be accessible only to authorized users, yet the system reveals enough information through redirect responses to enable unauthorized discovery of album content. This type of information leakage can be leveraged in conjunction with other attack vectors to create more comprehensive compromise scenarios. The vulnerability also impacts the overall security posture of the application by demonstrating weak access control mechanisms and insufficient input sanitization that could potentially expose other sensitive information within the system.
The remediation approach for this vulnerability requires immediate attention to the application's URL handling and access control logic. The most effective solution involves implementing proper access controls that prevent any information disclosure through redirect responses, regardless of whether the requested permalink ID exists or is accessible to the requesting user. This includes modifying the redirect behavior to strip or obscure any descriptive information from redirect URLs, implementing rate limiting to prevent systematic enumeration attacks, and ensuring that all permalink ID access requests are properly authenticated and authorized. Organizations should also consider implementing more robust ID generation algorithms that are not easily predictable, and should conduct thorough security testing to identify similar information disclosure vulnerabilities within the application. The fix should align with security standards such as those outlined in CWE-200, which addresses information exposure, and should be implemented in accordance with ATT&CK framework techniques related to reconnaissance and credential access. Additionally, system administrators should review and strengthen their monitoring capabilities to detect and respond to potential enumeration attempts that could exploit this vulnerability.