CVE-2020-23834 in BarracudaDrive
Summary
by MITRE
Insecure Service File Permissions in the bd service in Real Time Logic BarracudaDrive v6.5 allow local attackers to escalate privileges to admin by replacing the %SYSTEMDRIVE%\bd\bd.exe file. When the computer next starts, the new bd.exe will be run as LocalSystem.
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Analysis
by VulDB Data Team • 11/12/2020
The vulnerability identified as CVE-2020-23834 resides within the bd service component of Real Time Logic BarracudaDrive version 6.5, representing a critical privilege escalation flaw that directly impacts system security. This issue stems from insecure service file permissions that create an exploitable condition allowing local attackers to gain administrative privileges through a straightforward yet dangerous method of service binary replacement. The vulnerability specifically targets the %SYSTEMDRIVE%dd.exe file location, which serves as the service executable that runs with LocalSystem privileges during system startup, making it a prime target for malicious exploitation.
The technical flaw manifests through improper permission controls on the service executable file, which should typically require administrative privileges to modify but instead allows local users to overwrite or replace the binary. This misconfiguration creates a path for privilege escalation where an attacker with local access can simply replace the legitimate bd.exe file with a malicious payload that will execute with the highest system privileges. The vulnerability operates under the principle that service binaries should be protected against unauthorized modification, yet the service in question fails to enforce proper access controls, allowing any local user to modify the service executable file. This flaw aligns with CWE-276, which addresses incorrect permissions for critical resources, and represents a classic case of insufficient privilege separation in service management.
The operational impact of this vulnerability is severe and immediate, as it enables any local attacker to achieve system compromise without requiring additional attack vectors or elevated privileges. Once the malicious bd.exe file is successfully placed in the target location, the attacker gains persistent administrative access to the system through the service execution mechanism that runs with LocalSystem privileges. This creates a persistent backdoor that can be leveraged for further lateral movement, data exfiltration, or establishment of additional footholds within the network. The attack requires minimal sophistication and can be executed automatically during system startup, making it particularly dangerous for environments where local access might be obtained through social engineering, compromised credentials, or other initial access vectors.
Mitigation strategies for CVE-2020-23834 should focus on immediate permission hardening and service configuration adjustments to prevent unauthorized modification of service binaries. Organizations should implement proper file system permissions that restrict write access to service executable files to only the SYSTEM account and authorized administrators. The service should be configured with appropriate access control lists that prevent local users from modifying critical service files. Additionally, implementing application whitelisting policies can prevent unauthorized executables from running with system privileges, while regular security audits should verify that service binaries maintain proper permissions. The remediation approach should align with ATT&CK technique T1068, which addresses local privilege escalation through service binary replacement, and requires comprehensive security hardening measures to prevent similar vulnerabilities across the system infrastructure.