CVE-2016-20024 in ZKTime
Summary
by MITRE • 03/16/2026
ZKTeco ZKTime.Net 3.0.1.6 contains an insecure file permissions vulnerability that allows unprivileged users to escalate privileges by modifying executable files. Attackers can exploit world-writable permissions on the ZKTimeNet3.0 directory and its contents to replace executable files with malicious binaries for privilege escalation.
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Analysis
by VulDB Data Team • 03/16/2026
The vulnerability identified as CVE-2016-20024 affects ZKTeco ZKTime.Net version 3.0.1.6, representing a critical security flaw that undermines the integrity of the system through improper file permission configuration. This vulnerability resides within the ZKTimeNet3.0 directory structure where world-writable permissions are improperly configured, creating an exploitable condition that allows any user to modify critical system files. The flaw stems from inadequate access control mechanisms that fail to enforce proper file system permissions, specifically permitting write access to executable components that should be restricted to authorized administrative users only. This misconfiguration creates a fundamental weakness in the system's security model that directly violates established security principles of least privilege and principle of least authority.
The technical exploitation of this vulnerability involves a straightforward yet effective privilege escalation technique that leverages the insecure file permissions to replace legitimate executable files with malicious binaries. Attackers can identify the world-writable directory structure and substitute critical executables with compromised versions that execute with elevated privileges when launched by the system. This approach bypasses normal authentication and authorization mechanisms, allowing unprivileged users to gain administrative access to the system. The vulnerability specifically targets the executable files within the ZKTimeNet3.0 directory, where the attacker can modify or replace binaries that are subsequently executed by the system with elevated privileges. This type of attack directly maps to CWE-732, which describes improper permission assignment for critical resources, and represents a classic example of privilege escalation through file system manipulation.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential system compromise and data integrity violations. Once exploited, attackers can gain full administrative control over the affected system, enabling them to install additional malware, modify system configurations, access sensitive data, and potentially establish persistent access. The vulnerability affects the integrity and availability of the ZKTime.Net application, as malicious modifications can disrupt normal system operations or introduce backdoors for future exploitation. Organizations using this software face significant risk of unauthorized access and potential data breaches, particularly in environments where physical security is inadequate and unauthorized users may gain access to the system. The impact is particularly severe in time and attendance systems that often contain sensitive employee data and may be integrated with other corporate systems.
Mitigation strategies for this vulnerability must address the root cause through proper file system permission configuration and access control enforcement. System administrators should immediately correct the world-writable permissions on the ZKTimeNet3.0 directory and all its contents, ensuring that only authorized users have write access to executable files. The recommended approach involves implementing restrictive file permissions that prevent unauthorized modification of critical system components while maintaining necessary functionality for legitimate administrative tasks. Organizations should also consider implementing additional security controls such as file integrity monitoring, regular permission audits, and privilege access reviews to detect and prevent similar issues. The remediation process should include validating that all executable files within the application directory maintain appropriate permissions and that no world-writable directories exist that could serve as attack vectors. This vulnerability highlights the importance of proper security configuration management and demonstrates how simple permission misconfigurations can lead to severe privilege escalation exploits that compromise entire systems.