CVE-2017-15549 in Avamar Server
Summary
by MITRE
An issue was discovered in EMC Avamar Server 7.1.x, 7.2.x, 7.3.x, 7.4.x, 7.5.0; EMC NetWorker Virtual Edition (NVE) 9.0.x, 9.1.x, 9.2.x; and EMC Integrated Data Protection Appliance 2.0. A remote authenticated malicious user with low privileges could potentially upload arbitrary maliciously crafted files in any location on the server file system.
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Analysis
by VulDB Data Team • 12/20/2019
The vulnerability CVE-2017-15549 represents a critical file upload flaw in multiple EMC data protection products including Avamar Server and NetWorker Virtual Edition systems. This security weakness stems from insufficient input validation and access control mechanisms within the file handling processes of these enterprise backup solutions. The vulnerability affects versions spanning multiple release lines including Avamar Server 7.1.x through 7.5.0, NetWorker Virtual Edition 9.0.x through 9.2.x, and Integrated Data Protection Appliance 2.0. The flaw allows authenticated users with minimal privileges to bypass normal file system restrictions and upload malicious files to arbitrary locations on the target server.
From a technical perspective, this vulnerability falls under CWE-434 which describes "Unrestricted Upload of File with Dangerous Type" and aligns with ATT&CK technique T1195.001 for "Supply Chain Compromise" and T1059.001 for "Command and Scripting Interpreter". The root cause lies in the lack of proper file type validation and directory traversal controls during the file upload process. When authenticated users submit files through the system's web interface or API endpoints, the application fails to properly sanitize file names, extensions, or paths, allowing attackers to manipulate the upload destination and execute malicious code. This issue particularly affects systems where the web application runs with elevated privileges, creating a path for privilege escalation and remote code execution.
The operational impact of this vulnerability extends beyond simple unauthorized file placement and represents a significant threat to enterprise data protection environments. Attackers can leverage this flaw to upload web shells, malware, or other malicious executables that could compromise the entire backup infrastructure. The implications are particularly severe given that these systems typically contain sensitive backup data and operate with high-privilege accounts. Once exploited, the vulnerability enables attackers to gain persistent access to the backup server, potentially leading to data exfiltration, system compromise, or disruption of critical backup operations. The vulnerability also poses risks to network integrity as compromised backup servers often serve as entry points for lateral movement within enterprise environments.
Mitigation strategies for CVE-2017-15549 should prioritize immediate patching of affected systems with the vendor-provided security updates. Organizations must implement strict file validation controls including MIME type checking, file extension filtering, and mandatory file content verification. Network segmentation and privileged account management should be enhanced to limit the potential impact of successful exploitation. Security monitoring should be configured to detect unusual file upload activities and unauthorized access attempts to backup server systems. Additionally, organizations should conduct comprehensive security assessments of their backup infrastructure and implement principle of least privilege controls for all user accounts accessing these systems. The vulnerability also highlights the importance of regular security testing and vulnerability management programs to identify and remediate similar issues before they can be exploited by malicious actors.