CVE-2019-7487 in SSLVPN NACagent
Summary
by MITRE
Installation of the SonicOS SSLVPN NACagent 3.5 on the Windows operating system, an autorun value is created does not put the path in quotes, so if a malicious binary by an attacker within the parent path could allow code execution.
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Analysis
by VulDB Data Team • 12/20/2019
The vulnerability identified as CVE-2019-7487 represents a critical security flaw in the SonicOS SSLVPN NACagent version 3.5 installation process on Windows systems. This issue stems from improper handling of file paths during the installation procedure, creating an exploitable condition that adversaries can leverage for privilege escalation and code execution. The vulnerability specifically affects the Windows operating system and manifests during the installation phase when the NACagent component is deployed.
The technical root cause of this vulnerability lies in the installation routine's failure to properly quote file paths when creating autorun registry entries. When the installer generates autorun values, it constructs paths without enclosing them in quotation marks, which creates a path traversal opportunity. This flaw directly maps to CWE-78, which addresses improper neutralization of special elements used in OS commands, and CWE-22, concerning improper limitation of a pathname to a restricted directory. The absence of proper path quoting allows attackers to manipulate the installation environment by placing malicious executables in parent directories that are part of the search path.
The operational impact of this vulnerability is significant as it enables attackers to achieve code execution with elevated privileges during the installation process. An attacker who can influence the parent directory containing the NACagent installation files can place a malicious binary with the same name as the expected executable, causing the system to execute the malicious code instead of the legitimate program. This represents a classic privilege escalation vector where the attacker leverages the installation process to gain unauthorized access to the system. The vulnerability is particularly dangerous because it occurs during legitimate system installation activities when users typically have elevated privileges.
The attack surface for this vulnerability extends beyond simple exploitation as it provides a persistent foothold for attackers within the target environment. According to the MITRE ATT&CK framework, this vulnerability aligns with techniques such as T1068 (Local Port Forwarding) and T1059 (Command and Scripting Interpreter) by enabling the execution of arbitrary code. The flaw essentially creates an automated execution point that can be leveraged for various malicious activities including data exfiltration, lateral movement, or establishment of backdoors. Security professionals should consider this vulnerability as part of a broader attack chain that could lead to complete system compromise, especially in environments where SonicOS SSLVPN NACagent is deployed.
Mitigation strategies for CVE-2019-7487 should focus on immediate remediation through official vendor patches and updates. Organizations must ensure that all affected systems have the latest SonicOS firmware and NACagent versions installed to address the path quoting issue. Additionally, system administrators should implement proper access controls and privilege separation during installation processes to minimize the impact of such vulnerabilities. Network segmentation and monitoring of installation activities can help detect potential exploitation attempts. The vulnerability underscores the importance of secure coding practices and proper input validation in installation routines, particularly when dealing with file paths and registry modifications. Regular security assessments and vulnerability scanning should include checks for similar path handling issues across all installed software components to prevent similar vulnerabilities from being exploited in the future.