CVE-2014-7271 in Desktop Display Manager
Summary
by MITRE
Simple Desktop Display Manager (SDDM) before 0.10.0 allows local users to log in as user "sddm" without authentication.
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Analysis
by VulDB Data Team • 02/17/2023
The Simple Desktop Display Manager (SDDM) vulnerability identified as CVE-2014-7271 represents a critical authentication bypass flaw that affected versions prior to 0.10.0. This vulnerability specifically enables local attackers to gain unauthorized access to the system by logging in as the dedicated sddm user account without providing any credentials. The issue stems from improper authentication handling within the display manager's login process, creating a security weakness that undermines the fundamental purpose of the authentication mechanism.
The technical flaw manifests in the SDDM's handling of user authentication during the login sequence. When a user attempts to log in through the display manager, the system should validate credentials against the appropriate user database or authentication service. However, in vulnerable versions, the authentication process fails to properly verify user credentials, allowing any local user to bypass the authentication step and assume the identity of the sddm user. This flaw operates at the authentication layer and represents a classic case of insufficient authentication checks, which aligns with CWE-287 - Improper Authentication. The vulnerability specifically affects the display manager's authentication flow rather than the underlying system authentication mechanisms, making it particularly concerning for desktop environments that rely heavily on graphical login interfaces.
The operational impact of this vulnerability extends beyond simple unauthorized access to the sddm user account. While the immediate threat may appear limited to accessing a dedicated display manager user, this authentication bypass creates potential for privilege escalation and lateral movement within the system. An attacker who successfully exploits this vulnerability could potentially leverage the sddm user account to access system resources, modify configuration files, or gain access to other services running under the same user context. The vulnerability also compromises the integrity of the display manager's security model, as it undermines the trust model that should exist between the authentication system and the graphical login interface. From an ATT&CK perspective, this vulnerability maps to T1078 - Valid Accounts and T1547 - Boot or Logon Autostart Execution, as unauthorized access to system accounts can enable further malicious activities.
Mitigation strategies for CVE-2014-7271 should prioritize immediate patching of affected SDDM installations to version 0.10.0 or later, which includes the necessary authentication fixes. System administrators should also implement additional security controls such as restricting local access to systems running SDDM, implementing proper user account management policies, and monitoring for unauthorized access attempts. The vulnerability highlights the importance of maintaining current software versions and conducting regular security assessments of desktop environments. Organizations should also consider implementing additional layers of authentication and access controls, particularly for accounts that serve system management functions like sddm. Proper configuration of the display manager should include disabling unnecessary authentication bypasses and ensuring that all user accounts have appropriate access controls and monitoring in place. The fix for this vulnerability demonstrates the critical importance of proper authentication implementation in graphical user interfaces and the potential security implications of inadequate credential validation in desktop environments.