CVE-2016-5821 in HiSuite
Summary
by MITRE
Huawei HiSuite before 4.0.4.204_ove (Out of China) and before 4.0.4.301 (China) use a weak ACL (FILE_WRITE_DATA for BUILTIN\Users) for the HiSuite service directory, which allows local users to gain SYSTEM privileges via a Trojan horse (1) SspiCli.dll or (2) USERENV.dll file or possibly other unspecified DLL files.
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Analysis
by VulDB Data Team • 09/02/2022
The vulnerability identified as CVE-2016-5821 represents a critical privilege escalation flaw in Huawei HiSuite software versions prior to 4.0.4.204_ove and 4.0.4.301. This issue stems from improper access control configuration within the HiSuite service directory, creating a dangerous security boundary that malicious actors can exploit to elevate their privileges from standard user level to SYSTEM level. The vulnerability specifically manifests through weak access control list configurations that grant write permissions to the BUILTIN\Users group, allowing local users to manipulate critical system components.
The technical exploitation mechanism involves placing malicious dynamic link library files within the HiSuite service directory, specifically targeting SspiCli.dll and USERENV.dll components. These DLL files are critical system components that, when replaced or modified by an attacker, can trigger privilege escalation when executed by the system. The vulnerability classifies under CWE-276, which addresses improper file permissions and access control mechanisms, and aligns with ATT&CK technique T1068, which covers local privilege escalation through system binary modification. The flaw demonstrates a fundamental failure in the principle of least privilege, where the service directory permissions are overly permissive for a system-critical application.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with complete system control capabilities. Once elevated to SYSTEM privileges, malicious users can execute arbitrary code, modify system files, access sensitive data, and potentially establish persistent backdoors within the compromised system. This vulnerability is particularly concerning because it requires minimal user interaction for exploitation, as the malicious DLL files can be placed in the service directory through normal user operations, making it a stealthy and effective attack vector.
Mitigation strategies for CVE-2016-5821 should prioritize immediate software updates to versions 4.0.4.204_ove or 4.0.4.301, which address the weak ACL configuration. System administrators should also implement additional security measures including regular permission audits of system directories, monitoring for unauthorized DLL file modifications, and implementing application whitelisting policies to prevent execution of unsigned or unexpected DLL files. The vulnerability highlights the importance of proper access control implementation and demonstrates how weak permissions in service directories can create significant security risks that extend far beyond the initial scope of the vulnerable application itself.