CVE-2021-3579 in Endpoint Security Tools
Summary
by MITRE • 10/28/2021
Incorrect Default Permissions vulnerability in the bdservicehost.exe and Vulnerability.Scan.exe components as used in Bitdefender Endpoint Security Tools for Windows, Total Security allows a local attacker to elevate privileges to NT AUTHORITY\SYSTEM This issue affects: Bitdefender Endpoint Security Tools for Windows versions prior to 7.2.1.65. Bitdefender Total Security versions prior to 7.2.1.65.
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Analysis
by VulDB Data Team • 11/03/2021
The vulnerability identified as CVE-2021-3579 represents a critical privilege escalation flaw within Bitdefender's endpoint security suite that affects both Endpoint Security Tools and Total Security products for Windows. This issue stems from incorrect default permissions assigned to critical system components, specifically bdservicehost.exe and Vulnerability.Scan.exe processes that operate with elevated privileges. The vulnerability allows local attackers to exploit these misconfigured permissions and elevate their access level from standard user privileges to the highest system level authority known as NT AUTHORITY\SYSTEM. This privilege escalation capability fundamentally compromises the security posture of affected systems by providing attackers with complete control over the target machine.
The technical root cause of this vulnerability lies in the improper implementation of access control mechanisms within Bitdefender's security components. When these processes execute with overly permissive default permissions, they create attack vectors that malicious actors can exploit to gain unauthorized system-level access. The flaw specifically affects versions prior to 7.2.1.65 of both Bitdefender Endpoint Security Tools and Total Security, indicating that this was a widespread issue across the product line that required a specific version update to remediate. The bdservicehost.exe and Vulnerability.Scan.exe components are designed to operate with elevated privileges to perform their security functions, but the default permission settings were not properly restricted, allowing unauthorized access to these privileged processes.
From an operational impact perspective, this vulnerability poses significant risks to enterprise environments where Bitdefender products are deployed. Attackers who gain access to a system through other means can leverage this privilege escalation flaw to bypass traditional security controls and gain complete system compromise. The implications extend beyond individual machine compromise as attackers can use the elevated privileges to install persistent backdoors, modify system files, access sensitive data, and potentially move laterally within network environments. This vulnerability directly violates the principle of least privilege and undermines the core security assumptions of the endpoint protection solution. The impact is particularly severe given that the attack requires only local access, meaning that even if network security controls are intact, a compromised local account can be used to achieve system-level control.
Organizations affected by CVE-2021-3579 should immediately implement mitigations including updating to Bitdefender versions 7.2.1.65 or later, which contain the necessary permission fixes. System administrators should also conduct thorough security assessments to identify any potential exploitation attempts and monitor for unusual system behavior that might indicate compromise. The vulnerability aligns with CWE-276, which describes improper permissions and access control issues, and represents a classic example of how insufficient access control can lead to privilege escalation attacks. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and can be used to achieve initial access and persistence within compromised systems. The remediation approach should include not only software patching but also enhanced monitoring of system processes and access controls to detect potential exploitation attempts.