CVE-2018-10852 in sssd
Summary
by MITRE
The UNIX pipe which sudo uses to contact SSSD and read the available sudo rules from SSSD has too wide permissions, which means that anyone who can send a message using the same raw protocol that sudo and SSSD use can read the sudo rules available for any user. This affects versions of SSSD before 1.16.3.
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Analysis
by VulDB Data Team • 03/29/2023
The vulnerability described in CVE-2018-10852 represents a critical access control flaw within the SSSD (System Security Services Daemon) component that integrates with sudo for authentication and authorization. This issue stems from improper permission settings on UNIX pipes used for communication between sudo and SSSD services, creating an exploitable path for unauthorized information disclosure. The flaw specifically impacts SSSD versions prior to 1.16.3, where the pipe permissions were configured too broadly, allowing any local user to intercept and read sudo rule configurations intended for specific users.
The technical implementation of this vulnerability involves the use of raw protocol communication channels that sudo employs to query SSSD for available sudo rules. When sudo needs to determine which commands a user can execute, it establishes a communication channel with SSSD through a UNIX pipe. Due to insufficient permission controls on this pipe, any user with access to the system can potentially send messages through the same raw protocol mechanism, effectively bypassing normal authorization checks. This misconfiguration creates a privilege escalation path where unauthorized users can gain knowledge of sudo rule configurations that should remain restricted to specific user groups or administrators.
The operational impact of this vulnerability extends beyond simple information disclosure, as it fundamentally undermines the security model of sudo-based access control systems. Attackers can leverage this flaw to enumerate available sudo rules across all users on the system, potentially discovering which commands are permitted for specific user accounts and identifying potential attack vectors. This reconnaissance capability enables more sophisticated attacks where adversaries can craft targeted exploitation strategies based on the discovered sudo configurations. The vulnerability particularly affects environments where SSSD is used for centralized authentication and where sudo rules are configured with varying levels of privilege for different user groups.
From a cybersecurity framework perspective, this vulnerability aligns with CWE-276, which addresses improper permissions for critical resources, and maps to ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation." The flaw represents a classic case of insufficient privilege separation in inter-process communication mechanisms, where the security boundary between sudo and SSSD was compromised due to overly permissive pipe permissions. Organizations utilizing SSSD for centralized authentication and sudo-based access control are particularly vulnerable, as this issue affects the fundamental trust model between these security components.
The recommended mitigation strategy involves upgrading SSSD to version 1.16.3 or later, where the pipe permission issue has been addressed through proper access control implementation. Additionally, system administrators should verify that all UNIX pipe permissions are appropriately configured with restrictive access controls, ensuring that only authorized processes can access sensitive communication channels. Regular security auditing of inter-process communication mechanisms and permission settings should be implemented as part of baseline security practices to prevent similar vulnerabilities from emerging in other system components. Organizations should also consider implementing monitoring solutions to detect unauthorized access attempts to sensitive system communication channels and establish proper incident response procedures for addressing such security flaws.