CVE-2019-1000 in Azure Active Directory Connect
Summary
by MITRE
An elevation of privilege vulnerability exists in Microsoft Azure Active Directory Connect build 1.3.20.0, which allows an attacker to execute two PowerShell cmdlets in context of a privileged account, and perform privileged actions.To exploit this, an attacker would need to authenticate to the Azure AD Connect server, aka 'Microsoft Azure AD Connect Elevation of Privilege Vulnerability'.
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Analysis
by VulDB Data Team • 09/17/2023
The vulnerability identified as CVE-2019-1000 represents a critical elevation of privilege flaw within Microsoft Azure Active Directory Connect software version 1.3.20.0. This security weakness specifically targets the authentication and authorization mechanisms of Azure AD Connect servers, creating a pathway for malicious actors to escalate their privileges from standard user access to privileged account contexts. The vulnerability stems from insufficient access controls and improper privilege management within the PowerShell execution environment of the Azure AD Connect service, which operates with elevated system permissions to perform directory synchronization functions.
The technical exploitation of this vulnerability occurs when an attacker successfully authenticates to the Azure AD Connect server through legitimate means, such as valid user credentials or compromised accounts. Once authenticated, the attacker can execute two specific PowerShell cmdlets that operate within the context of the privileged account that the Azure AD Connect service utilizes for directory synchronization operations. This privilege escalation mechanism directly violates the principle of least privilege and allows unauthorized individuals to perform administrative functions that should be restricted to authorized personnel only. The flaw exists because the PowerShell execution environment lacks proper validation of command origins and does not adequately restrict which commands can be executed with elevated privileges.
From an operational impact perspective, this vulnerability creates significant risk for organizations relying on Azure AD Connect for directory synchronization and identity management. Attackers who successfully exploit this vulnerability can perform a wide range of privileged actions including creating new user accounts, modifying existing user permissions, accessing sensitive directory information, and potentially establishing persistent backdoors within the directory service. The implications extend beyond simple privilege escalation as this vulnerability can serve as a foothold for broader network infiltration and lateral movement attacks. The attack vector is particularly concerning because it requires only authentication to the Azure AD Connect server, which may be accessible from network segments that are not as strictly controlled as primary administrative access points.
Organizations should implement multiple layers of mitigation to address this vulnerability including immediate patching of Azure AD Connect to versions that resolve the privilege escalation flaw, implementing strict network segmentation to limit access to Azure AD Connect servers, and deploying enhanced monitoring for PowerShell execution activities. The vulnerability aligns with CWE-276, which addresses improper privileges, and corresponds to techniques described in the MITRE ATT&CK framework under privilege escalation and defense evasion tactics. Security teams should also consider implementing privileged access management solutions, enabling detailed logging of PowerShell cmdlet executions, and conducting regular security assessments of directory synchronization services to identify similar privilege-related vulnerabilities across their infrastructure.
The remediation process requires organizations to update their Azure AD Connect installations to versions that contain the appropriate security patches and configuration changes. Additionally, administrators should review and tighten access controls to the Azure AD Connect server, implement just-in-time access provisioning, and establish comprehensive audit trails for all privileged activities. The vulnerability demonstrates the importance of maintaining current security patches and the critical need for proper privilege management in identity and access management systems. Organizations should also consider implementing additional security controls such as multi-factor authentication for administrative access and regular security assessments of their directory synchronization environments to prevent similar vulnerabilities from being exploited in the future.