CVE-2018-7937 in HiRouter-CD20-10
Summary
by MITRE
In Huawei HiRouter-CD20-10 with the versions before 1.9.6 and WS5200-10 with the versions before 1.9.6, there is a plug-in signature bypass vulnerability due to insufficient plug-in verification. An attacker may tamper with a legitimate plug-in to build a malicious plug-in and trick users into installing it. Successful exploit could allow the attacker to obtain the root permission of the device and take full control over the device.
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Analysis
by VulDB Data Team • 05/07/2023
The vulnerability identified as CVE-2018-7937 represents a critical security flaw in Huawei HiRouter-CD20-10 and WS5200-10 networking devices running firmware versions prior to 1.9.6. This issue stems from inadequate verification mechanisms within the device's plugin architecture, creating a pathway for malicious actors to compromise the device's integrity. The vulnerability specifically targets the plugin signature verification process, which is a fundamental security control designed to ensure only authorized and verified software components can be installed and executed on the device. When this verification fails, it creates an exploitable condition that undermines the device's security posture and trust model.
The technical implementation of this vulnerability allows attackers to manipulate legitimate plugin files through a process known as plugin signature bypass. By carefully modifying existing valid plugins, attackers can create malicious versions that appear authentic to the device's verification system. This technique exploits weaknesses in the cryptographic signature validation mechanisms that should prevent unauthorized modifications to the software components. The flaw essentially creates a false sense of security where the device accepts modified plugins as legitimate, enabling attackers to execute arbitrary code with elevated privileges. This bypass mechanism operates at the software integrity level and directly impacts the device's ability to maintain a secure boot process and validate software authenticity.
The operational impact of this vulnerability is severe and far-reaching, as successful exploitation grants attackers complete administrative control over the affected devices. Once a malicious plugin is installed and executed, the attacker gains root-level permissions, providing unrestricted access to all device functionalities including network configuration, user data access, and system-level operations. This complete compromise allows for persistent backdoor access, network monitoring, data exfiltration, and potential lateral movement within the network infrastructure. The vulnerability affects network security appliances that are often positioned at critical points in enterprise and home networks, making the potential impact of exploitation significant for both individual users and organizational security. The threat landscape for this vulnerability aligns with attack patterns described in the mitre ATT&CK framework under software supply chain compromise techniques and privilege escalation methods.
Security mitigations for CVE-2018-7937 primarily involve upgrading to firmware versions 1.9.6 or later, which contain corrected verification mechanisms for plugin signatures. Organizations should implement comprehensive firmware update policies to ensure all affected devices receive the necessary security patches. Network administrators should also consider implementing additional monitoring controls to detect unauthorized plugin installations or suspicious network activities that might indicate exploitation attempts. The vulnerability demonstrates the importance of robust software integrity verification processes and aligns with CWE-311, which addresses the absence of encryption for sensitive data, and CWE-312, concerning the exposure of sensitive data through cleartext storage or transmission. Organizations should also conduct thorough security assessments of their network infrastructure to identify other potentially vulnerable devices and implement layered security controls to prevent similar supply chain compromise scenarios.