CVE-2021-29092 in Photo Station
Summary
by MITRE • 06/02/2021
Unrestricted upload of file with dangerous type vulnerability in file management component in Synology Photo Station before 6.8.14-3500 allows remote authenticated users to execute arbitrary code via unspecified vectors.
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Analysis
by VulDB Data Team • 06/05/2021
The vulnerability identified as CVE-2021-29092 represents a critical security flaw within Synology Photo Station's file management component, affecting versions prior to 6.8.14-3500. This issue manifests as an unrestricted file upload vulnerability that permits authenticated users to upload files with potentially malicious extensions, creating a pathway for remote code execution. The flaw resides in the application's insufficient validation mechanisms for file types and content, allowing attackers to bypass security controls designed to prevent the upload of dangerous file formats. The vulnerability operates through unspecified vectors that leverage the application's trust in user-provided file metadata and extension validation.
This vulnerability directly maps to CWE-434, which describes "Unrestricted Upload of File with Dangerous Type," a well-documented weakness in software applications that fail to properly validate file uploads. The technical implementation flaw stems from inadequate input sanitization and validation processes within the Photo Station's file handling subsystem. Attackers can exploit this by uploading files with extensions that appear benign but contain malicious payloads, or by manipulating file headers to trick the application into treating executable files as safe media formats. The authentication requirement reduces the attack surface but does not eliminate the risk, as any authenticated user with access to the Photo Station component can potentially leverage this vulnerability.
The operational impact of CVE-2021-29092 is severe and multifaceted, as it enables remote code execution capabilities that can compromise entire network infrastructures. Once exploited, the vulnerability allows attackers to execute arbitrary code on the affected Synology device, potentially leading to full system compromise, data exfiltration, or use as a pivot point for attacking other networked systems. The threat landscape for this vulnerability aligns with ATT&CK technique T1059.007, which covers "Command and Scripting Interpreter: PowerShell," as attackers can leverage the uploaded malicious files to execute PowerShell scripts or other system commands. The vulnerability particularly affects organizations relying on Synology NAS devices for media storage, as it provides a direct path for attackers to gain persistent access to network resources.
Mitigation strategies for CVE-2021-29092 must address both immediate remediation and long-term security improvements. The primary and most effective solution involves upgrading to Synology Photo Station version 6.8.14-3500 or later, which includes proper file type validation and restriction mechanisms. Organizations should implement additional security controls such as restricting file upload capabilities to specific, verified extensions, implementing strict file content validation using multiple verification methods, and establishing robust access controls to minimize the attack surface. Network segmentation and monitoring solutions should be deployed to detect suspicious file upload activities, while regular security audits should verify that file handling processes properly validate both file extensions and content signatures. The vulnerability also underscores the importance of following secure coding practices and implementing defense-in-depth strategies that go beyond simple perimeter security measures.