CVE-2015-7699 in Server
Summary
by MITRE
The files_external app in ownCloud Server before 7.0.9, 8.0.x before 8.0.7, and 8.1.x before 8.1.2 allows remote authenticated users to instantiate arbitrary classes and possibly execute arbitrary code via a crafted mount point option, related to "objectstore."
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Analysis
by VulDB Data Team • 04/01/2025
The vulnerability CVE-2015-7699 represents a critical security flaw in the files_external app of ownCloud Server versions prior to specific patch releases. This issue affects the authentication and authorization mechanisms within the cloud storage platform, creating a pathway for malicious actors to exploit the system's object storage functionality. The vulnerability specifically targets the way the application handles mount point options, which are used to configure external storage connections within the ownCloud environment.
The technical exploitation occurs through a deserialization vulnerability that allows authenticated users to manipulate the mount point configuration parameters. When users provide crafted input through the mount point options, the system fails to properly validate or sanitize the input before processing it as part of an object storage instantiation. This improper handling creates a code injection vector where attackers can inject malicious class instantiation commands that are subsequently executed by the server. The vulnerability stems from insufficient input validation and unsafe object deserialization practices within the external storage module.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it allows attackers to potentially execute arbitrary code on the affected server. This capability enables attackers to gain full control over the system, potentially leading to data breaches, privilege escalation, and complete system compromise. The vulnerability affects multiple versions of ownCloud, indicating a widespread exposure across the user base, and the fact that it requires only authenticated access makes it particularly dangerous in environments where user accounts are not properly secured. The objectstore functionality is commonly used in enterprise environments, making this vulnerability particularly concerning for organizations relying on external storage integrations.
Security professionals should implement immediate mitigations including updating to the patched versions of ownCloud Server, specifically versions 7.0.9, 8.0.7, and 8.1.2, which contain the necessary fixes. Organizations should also review and restrict user permissions for external storage configuration, implement network segmentation to limit access to the ownCloud server, and conduct thorough security audits of all external storage integrations. This vulnerability aligns with CWE-502 which addresses unsafe deserialization, and maps to ATT&CK technique T1059.007 for command and script injection, highlighting the need for comprehensive security controls across multiple threat vectors. The vulnerability demonstrates the critical importance of input validation and secure coding practices when handling user-supplied data in enterprise storage solutions.