CVE-2017-7283 in Enterprise Backup
Summary
by MITRE
An authenticated user of Unitrends Enterprise Backup before 9.1.2 can execute arbitrary OS commands by sending a specially crafted filename to the /api/restore/download-files endpoint, related to the downloadFiles function in api/includes/restore.php.
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Analysis
by VulDB Data Team • 09/17/2020
The vulnerability identified as CVE-2017-7283 represents a critical command injection flaw within the Unitrends Enterprise Backup software ecosystem. This issue affects versions prior to 9.1.2 and stems from inadequate input validation mechanisms within the restore functionality of the backup solution. The vulnerability specifically manifests when an authenticated user interacts with the /api/restore/download-files endpoint, which processes file download requests through the downloadFiles function located in api/includes/restore.php. The flaw allows for arbitrary OS command execution, fundamentally compromising the integrity and security posture of the affected system.
The technical implementation of this vulnerability demonstrates a classic command injection attack vector where user-supplied input is directly incorporated into system commands without proper sanitization or escaping mechanisms. When an authenticated user submits a specially crafted filename parameter to the vulnerable endpoint, the system processes this input within a shell execution context. This design flaw enables attackers to inject malicious commands that get executed with the privileges of the backup service account. The vulnerability maps directly to CWE-77 which defines command injection as the injection of a command into a shell, and aligns with ATT&CK technique T1059.001 for command and script interpreters. The attack chain begins with authentication and proceeds through exploitation of the input validation weakness to achieve remote code execution.
The operational impact of this vulnerability extends far beyond simple data compromise, as it provides attackers with complete control over the backup server's operating system. An attacker who successfully exploits this vulnerability can execute arbitrary commands with the privileges of the backup service, potentially leading to full system compromise, data exfiltration, or lateral movement within the network. The authenticated nature of the attack means that an attacker must first gain valid credentials, but this access is typically sufficient to escalate privileges and execute malicious payloads. Organizations using affected versions of Unitrends Enterprise Backup face significant risk of unauthorized access, data loss, and potential system infiltration. The vulnerability affects backup operations and data recovery processes, which are critical components of enterprise disaster recovery strategies, making this a particularly dangerous flaw in backup and recovery systems.
Mitigation strategies for CVE-2017-7283 require immediate implementation of the vendor-provided security patch for Unitrends Enterprise Backup version 9.1.2 or later. Organizations should also implement network segmentation to limit access to backup systems and restrict API endpoint access to trusted administrative networks. Additional protective measures include implementing strict input validation controls, monitoring API access logs for suspicious patterns, and conducting regular security assessments of backup infrastructure. Security teams should also consider implementing web application firewalls to detect and block malicious requests targeting the vulnerable endpoint. The remediation process should include credential rotation for backup service accounts and comprehensive monitoring of system access patterns to detect potential exploitation attempts. Organizations should also review their backup and recovery procedures to ensure that any compromised systems are properly isolated and investigated before restoration operations resume.