CVE-2020-8093 in BitDefender
Summary
by MITRE
A vulnerability in the AntivirusforMac binary as used in Bitdefender Antivirus for Mac allows an attacker to inject a library using DYLD environment variable to cause third-party code execution
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Analysis
by VulDB Data Team • 03/27/2024
The vulnerability identified as CVE-2020-8093 resides within the AntivirusforMac binary component of Bitdefender Antivirus for Mac, representing a critical security flaw that enables arbitrary code execution through dynamic library injection techniques. This vulnerability specifically affects the application's handling of dynamic library loading mechanisms, creating an attack vector that can be exploited by malicious actors to execute unauthorized code within the context of the antivirus application. The flaw manifests when the application fails to properly validate or sanitize dynamic library loading paths, allowing attackers to manipulate the dynamic linker's behavior through environment variable manipulation.
The technical exploitation of this vulnerability leverages the DYLD environment variables, specifically DYLD_LIBRARY_PATH and DYLD_INSERT_LIBRARIES, which are fundamental components of macOS dynamic linking infrastructure. When an application loads these variables, it can be tricked into loading attacker-controlled libraries instead of legitimate system libraries. The vulnerability stems from insufficient input validation within the AntivirusforMac binary, which does not properly restrict or sanitize the dynamic library loading process. This design flaw aligns with CWE-426, which addresses the insecure loading of dynamic libraries, and represents a classic example of a library injection attack that can bypass standard security controls. The attack requires minimal privileges since it operates within the context of the legitimate antivirus application, making it particularly dangerous as it can evade detection mechanisms that might otherwise identify malicious code execution.
The operational impact of CVE-2020-8093 extends beyond simple code execution, as it provides attackers with a persistent foothold within the system through the antivirus application's elevated privileges and trusted status. Since Bitdefender Antivirus for Mac operates with significant system access rights to monitor and control security functions, successful exploitation can enable attackers to gain comprehensive system control, data exfiltration capabilities, and potential privilege escalation to administrator level access. The vulnerability also creates opportunities for advanced persistent threat actors to establish backdoors or deploy additional malware payloads that can persist across system reboots. This threat model aligns with ATT&CK technique T1548.001, which describes abuse of dynamic-link library injection for privilege escalation, and T1059.001, which covers the use of scripting languages for code execution. The attack surface is particularly concerning because antivirus applications are typically granted extensive system permissions, making them attractive targets for attackers seeking to maintain long-term system access.
Mitigation strategies for CVE-2020-8093 should focus on both immediate patching and operational security enhancements. Organizations must ensure that all affected systems receive the latest Bitdefender updates that address this vulnerability through proper dynamic library loading validation and environment variable sanitization. System administrators should implement monitoring for suspicious environment variable usage patterns and establish strict controls over dynamic library loading within security applications. The solution approach should incorporate principle of least privilege principles, ensuring that antivirus applications do not operate with unnecessary elevated privileges. Security teams should also consider implementing application whitelisting policies that restrict which libraries can be loaded by security applications, and establish regular security audits to detect potential exploitation attempts. Additionally, network monitoring should be enhanced to detect unusual library loading behaviors that might indicate exploitation attempts, particularly focusing on outbound connections or file access patterns that could suggest data exfiltration activities. The vulnerability serves as a reminder of the importance of secure coding practices in security applications and the critical need for proper input validation and environment variable handling in system-level software components.