CVE-2019-7201 in NetBak Replicator
Summary
by MITRE
An unquoted service path vulnerability is reported to affect the service ?QVssService? in QNAP NetBak Replicator. This vulnerability could allow an authorized but non-privileged local user to execute arbitrary code with elevated system privileges. QNAP have already fixed this issue in QNAP NetBak Replicator 4.5.12.1108.
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Analysis
by VulDB Data Team • 12/05/2019
The vulnerability identified as CVE-2019-7201 represents a critical unquoted service path flaw within the QNAP NetBak Replicator software ecosystem. This issue specifically targets the QVssService component, which operates as a Windows service responsible for volume shadow copy operations within the backup infrastructure. The vulnerability stems from improper service path configuration where the executable path contains spaces but lacks proper quotation marks around the path string. This configuration allows an attacker to place malicious executables in directories along the path before the actual service executable, enabling privilege escalation attacks.
The technical exploitation of this vulnerability follows established patterns documented in CWE-16 and aligns with ATT&CK technique T1068 which covers privilege escalation through service misconfiguration. When the QVssService starts, it follows a path resolution mechanism that traverses directories without proper quoting, creating opportunities for path manipulation attacks. An authorized but non-privileged local user can leverage this flaw by placing a malicious executable with the same name as the service in a directory that appears earlier in the Windows search path. The service will then execute the attacker's malicious binary with the elevated privileges of the system account, typically SYSTEM or Local System level permissions.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides a persistent foothold for attackers within the network infrastructure. The QNAP NetBak Replicator serves as a backup solution for enterprise environments, making this vulnerability particularly dangerous when considering that backup systems often contain sensitive data and may operate with elevated privileges. Attackers could potentially access backed-up data, modify backup configurations, or establish persistence mechanisms within the organization's backup infrastructure. This threat is compounded by the fact that backup systems are often overlooked in security assessments and may contain credentials or data that could be used for lateral movement within the network.
QNAP addressed this vulnerability in version 4.5.12.1108 through proper service path quoting implementation, which ensures that Windows resolves the service executable path correctly without allowing path manipulation attacks. Organizations should prioritize immediate deployment of this patch across all affected systems, particularly those running older versions of the NetBak Replicator software. Security teams should also conduct comprehensive audits of service configurations across their environments to identify similar unquoted path vulnerabilities in other services, as this represents a common misconfiguration pattern that can affect numerous Windows-based applications. Additionally, implementing proper access controls and monitoring for unauthorized file modifications in service directories can provide additional defense-in-depth measures against exploitation attempts.