CVE-2018-20735 in Patrol Agent
Summary
by MITRE
** DISPUTED ** An issue was discovered in BMC PATROL Agent through 11.3.01. It was found that the PatrolCli application can allow for lateral movement and escalation of privilege inside a Windows Active Directory environment. It was found that by default the PatrolCli / PATROL Agent application only verifies if the password provided for the given username is correct; it does not verify the permissions of the user on the network. This means if you have PATROL Agent installed on a high value target (domain controller), you can use a low privileged domain user to authenticate with PatrolCli and then connect to the domain controller and run commands as SYSTEM. This means any user on a domain can escalate to domain admin through PATROL Agent. NOTE: the vendor disputes this because they believe it is adequate to prevent this escalation by means of a custom, non-default configuration.
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Analysis
by VulDB Data Team • 06/18/2024
The vulnerability identified as CVE-2018-20735 resides within the BMC PATROL Agent software version 11.3.01 and earlier, presenting a significant security weakness that enables unauthorized privilege escalation within Windows Active Directory environments. This flaw fundamentally stems from the PatrolCli application's authentication mechanism which fails to validate user permissions beyond basic credential verification. The issue creates a dangerous scenario where authentication is decoupled from authorization, allowing attackers to exploit the system through lateral movement techniques that bypass normal security controls. The vulnerability operates under the principle that authentication should not automatically imply authorization, a core tenet of secure system design that this implementation fails to maintain.
The technical implementation flaw manifests when the PatrolCli application accepts credentials without verifying the authenticated user's permissions within the Active Directory environment. This creates a pathway for privilege escalation where a low-privileged domain user can authenticate against a target system running PATROL Agent and subsequently execute commands with elevated privileges. The vulnerability specifically impacts domain controllers and other high-value targets where PATROL Agent is deployed, as these systems typically require elevated permissions to function properly. The authentication process only validates password correctness rather than enforcing proper access controls, creating a critical gap that allows attackers to leverage legitimate authentication mechanisms for unauthorized access. This behavior directly violates the principle of least privilege and demonstrates a failure in implementing proper authorization checks within the authentication flow.
The operational impact of this vulnerability extends far beyond simple privilege escalation, as it enables attackers to gain SYSTEM-level access on domain controllers and other critical systems through the PATROL Agent infrastructure. This creates a significant attack surface where any domain user can potentially escalate their privileges to domain administrator level, effectively undermining the entire Active Directory security model. The vulnerability allows for lateral movement within the network by exploiting the legitimate PATROL Agent processes, making detection more challenging as the malicious activities appear to originate from authorized systems. This type of vulnerability aligns with attack patterns documented in the MITRE ATT&CK framework under privilege escalation and lateral movement techniques, specifically targeting the domain controller as a high-value target for compromise. The impact is particularly severe because it operates at the network level rather than at individual system boundaries, potentially allowing for widespread compromise across the entire domain infrastructure.
Security mitigations for this vulnerability should focus on implementing proper authorization controls within the PATROL Agent configuration and ensuring that authentication mechanisms enforce appropriate access controls. Organizations should consider disabling or restricting the PatrolCli application where possible, or implementing additional authentication layers that verify user permissions beyond basic credential validation. The vendor's position that this can be addressed through custom configuration highlights the importance of proper security hardening and the need for organizations to implement comprehensive security policies rather than relying solely on default configurations. Security teams should implement network segmentation to limit access to PATROL Agent systems, utilize monitoring solutions to detect anomalous authentication patterns, and establish strict access controls for PATROL Agent installations. This vulnerability demonstrates the critical importance of following security best practices such as those outlined in NIST SP 800-53 and ISO 27001, which emphasize the need for proper authentication and authorization controls to prevent privilege escalation attacks. The configuration requirements should ensure that PATROL Agent systems enforce proper access controls and that the authentication mechanism validates not just credential correctness but also appropriate user permissions within the target environment.