CVE-2017-7158 in macOS
Summary
by MITRE
An issue was discovered in certain Apple products. macOS before 10.13.2 is affected. The issue involves the "Screen Sharing Server" component. It allows attackers to obtain root privileges for reading files by leveraging screen-sharing access.
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Analysis
by VulDB Data Team • 08/18/2024
The vulnerability identified as CVE-2017-7158 represents a critical privilege escalation flaw within Apple's macOS operating system affecting versions prior to 10.13.2. This security weakness resides within the Screen Sharing Server component, which is part of the system's remote desktop functionality. The vulnerability stems from improper privilege handling during screen sharing sessions, creating an exploitable condition that allows unprivileged attackers to escalate their access level to root privileges. The flaw specifically manifests when an attacker with screen-sharing access can leverage this capability to read files that would normally require administrative privileges, effectively bypassing the system's access controls.
The technical nature of this vulnerability aligns with CWE-269, which addresses improper privilege management in software systems. The Screen Sharing Server component fails to properly validate or restrict file access permissions during remote sessions, creating a pathway for attackers to escalate their privileges through legitimate screen-sharing functionality. This issue operates under the principle of privilege escalation where a lower-privilege user can gain elevated access by exploiting a flaw in the system's permission model. The vulnerability's exploitation requires only screen-sharing access, making it particularly dangerous as it can be leveraged by attackers who have already gained some level of access to the system through other means.
From an operational perspective, this vulnerability poses significant risks to organizations relying on macOS systems for their computing infrastructure. The ability to obtain root privileges through screen-sharing access means that attackers can bypass standard security controls and gain complete system control. This includes access to sensitive data, system configuration files, and the ability to install malicious software or establish persistent access. The vulnerability affects macOS versions before 10.13.2, making it a critical concern for organizations that have not yet updated their systems. The attack vector is particularly concerning because screen sharing is a legitimate and often necessary feature for system administration and remote support, creating a false sense of security around this functionality.
The mitigation strategy for CVE-2017-7158 centers primarily on updating to macOS 10.13.2 or later versions where Apple has implemented proper privilege controls within the Screen Sharing Server component. Organizations should also consider implementing network segmentation to limit screen-sharing access to only trusted users and systems. Additionally, monitoring for unauthorized screen-sharing sessions and implementing strict access controls for screen-sharing functionality can help reduce the attack surface. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques and can be categorized under T1068, which involves exploiting legitimate credentials and privileges to gain higher access levels. Security teams should also consider implementing endpoint detection and response solutions to monitor for suspicious file access patterns that might indicate exploitation attempts.
Organizations should conduct comprehensive vulnerability assessments to identify systems running affected macOS versions and prioritize remediation efforts accordingly. The vulnerability demonstrates the importance of proper privilege management in remote access systems and highlights the need for continuous security updates. Regular patch management processes should include verification of screen-sharing functionality and associated components to prevent similar issues from arising in the future. System administrators should also review and tighten access controls for screen-sharing features, ensuring that only authorized personnel have access to these capabilities while maintaining necessary administrative functions.