CVE-2016-2855 in Mobile Broadband HL Service
Summary
by MITRE
The Huawei Mobile Broadband HL Service 22.001.25.00.03 and earlier uses a weak ACL for the MobileBrServ program data directory, which allows local users to gain SYSTEM privileges by modifying VERSION.dll.
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Analysis
by VulDB Data Team • 08/22/2022
The vulnerability identified as CVE-2016-2855 affects Huawei Mobile Broadband HL Service versions 22.001.25.00.03 and earlier, representing a critical privilege escalation flaw that exploits weak access control mechanisms within the MobileBrServ program data directory. This issue demonstrates a fundamental failure in the security design of the Huawei mobile broadband service implementation, where insufficient access controls allow local attackers to manipulate critical system components.
The technical flaw resides in the inadequate access control list implementation for the MobileBrServ program data directory, which fails to properly restrict write permissions to sensitive system files. Specifically, the vulnerability enables local users to modify the VERSION.dll file, a critical component that likely contains version information and potentially executable code segments. This weakness stems from the service running with elevated privileges while maintaining overly permissive directory permissions that do not adequately protect against local modification attacks.
The operational impact of this vulnerability is severe as it allows any local user to escalate their privileges to SYSTEM level, effectively bypassing the operating system's security model. This privilege escalation capability provides attackers with complete control over the affected system, enabling them to install malicious software, modify system configurations, access sensitive data, and potentially establish persistent backdoors. The vulnerability is particularly dangerous because it requires no special privileges to exploit, making it accessible to any user with local access to the system.
From a cybersecurity perspective, this vulnerability maps to CWE-276, which addresses improper permissions for critical resources, and aligns with ATT&CK technique T1068, which covers privilege escalation through local exploits. The weakness demonstrates poor least privilege implementation where the service operates with unnecessary elevated permissions while failing to properly secure its data directory. The vulnerability also reflects inadequate secure coding practices in the development of system services that handle sensitive operations without proper input validation and access control enforcement.
Mitigation strategies should include immediate patching of the Huawei Mobile Broadband HL Service to the latest version that addresses the ACL weakness, implementing proper access control lists for all service directories, and conducting comprehensive security audits of system services. Organizations should also enforce the principle of least privilege by ensuring that services run with minimal required permissions and regularly review directory permissions to prevent unauthorized modifications. Additionally, system monitoring should be implemented to detect unauthorized changes to critical system files like VERSION.dll, and security awareness training should emphasize the dangers of local privilege escalation attacks.