CVE-2017-15550 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 access arbitrary files on the server file system in the context of the running vulnerable application via Path traversal.
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Analysis
by VulDB Data Team • 12/20/2019
The vulnerability identified as CVE-2017-15550 represents a critical path traversal flaw affecting multiple EMC data protection products including Avamar Server versions 7.1.x through 7.5.0, NetWorker Virtual Edition 9.0.x through 9.2.x, and Integrated Data Protection Appliance 2.0. This security weakness stems from inadequate input validation within the affected applications' file handling mechanisms, allowing unauthorized access to sensitive system files and directories. The vulnerability specifically impacts systems where the application processes user-supplied file paths without proper sanitization, creating an opportunity for attackers to navigate beyond intended directories and access restricted content. The flaw exists at the application layer where file system operations are performed, making it particularly dangerous as it can be exploited by authenticated users who may not possess elevated privileges. This issue aligns with CWE-22, which defines path traversal vulnerabilities as weaknesses that occur when applications allow access to files and directories outside of their intended scope through the manipulation of file paths. The attack vector requires an authenticated user with low privileges, which significantly broadens the potential threat landscape as it does not require initial compromise of administrative credentials.
The technical exploitation of this vulnerability involves a malicious user leveraging the application's insufficient validation of file path inputs to traverse the file system hierarchy and access arbitrary files. When the vulnerable application processes file requests, it fails to properly sanitize user-provided paths, allowing attackers to insert directory traversal sequences such as ../ or ..\ that enable navigation to parent directories. This allows an authenticated user to access sensitive files including configuration data, log files, and potentially system credentials stored within the application's file system. The impact extends beyond simple file access as the compromised application context provides attackers with the ability to read files that may contain sensitive information or system configuration details that could aid in further exploitation. The vulnerability is particularly concerning because it operates within the context of the running application, meaning that any files accessible through the application's file system permissions are potentially accessible to the attacker. This creates a scenario where an attacker could gain access to backup data, system logs, or configuration files that might contain passwords, encryption keys, or other sensitive information that could be used for additional attacks.
The operational impact of CVE-2017-15550 extends beyond immediate data access concerns to encompass broader security implications for organizations relying on EMC data protection solutions. Organizations using affected versions of these products face potential data breaches, compliance violations, and system integrity compromises that could affect their backup and recovery operations. The vulnerability could enable attackers to access backup data that may contain sensitive organizational information, potentially leading to data exposure incidents that violate regulatory requirements such as gdpr, hipaa, or other data protection laws. Furthermore, the ability to access system files and configuration data could allow attackers to gain intelligence about the system architecture, potentially enabling more sophisticated attacks such as privilege escalation or lateral movement within the network. The vulnerability affects critical infrastructure components used for data protection and backup operations, meaning that successful exploitation could disrupt business continuity and recovery processes. This risk is compounded by the fact that the vulnerability requires only low-privilege authentication, making it accessible to users who may have legitimate access to the system for backup operations but could misuse their credentials for malicious purposes.
Organizations should implement immediate mitigations including applying the latest security patches provided by EMC to address the path traversal vulnerability. System administrators should also implement additional protective measures such as restricting file system access permissions for the affected applications and implementing network segmentation to limit access to these systems. The principle of least privilege should be enforced by ensuring that users have only the minimum required permissions to perform their legitimate backup operations. Regular security assessments and monitoring of system logs should be conducted to detect potential exploitation attempts, with particular attention to unusual file access patterns or attempts to access system directories. Organizations should also consider implementing web application firewalls or other protective controls that can detect and block path traversal attempts at the network level. The vulnerability demonstrates the importance of proper input validation and secure coding practices, aligning with attack techniques documented in the mitre att&ck framework under the path traversal category. Additionally, organizations should review their backup and recovery procedures to ensure that sensitive data is properly protected and that access controls are appropriately configured to prevent unauthorized access to backup systems and data. Regular vulnerability scanning and penetration testing should be conducted to identify and remediate similar weaknesses in other systems and applications within the organization's infrastructure.