CVE-2008-4212 in Mac OS X
Summary
by MITRE
Unspecified vulnerability in rlogind in the rlogin component in Mac OS X 10.4.11 and 10.5.5 applies hosts.equiv entries to root despite what is stated in documentation, which might allow remote attackers to bypass intended access restrictions.
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Analysis
by VulDB Data Team • 06/01/2025
The vulnerability identified as CVE-2008-4212 represents a critical access control flaw within the rlogind component of Mac OS X versions 10.4.11 and 10.5.5. This issue specifically targets the rlogin service which provides remote login functionality using the rlogin protocol, a legacy authentication mechanism that predates more secure alternatives like SSH. The vulnerability manifests in a manner that directly contradicts the documented behavior of the hosts.equiv file processing, creating a security bypass condition that could enable unauthorized remote access to privileged system accounts. The rlogin service operates by consulting the hosts.equiv file to determine which remote hosts are trusted for authentication purposes, typically allowing automatic login without password verification for specific host combinations. When this vulnerability is exploited, the system fails to properly enforce access restrictions as outlined in the documentation, allowing attackers to gain root access through trusted host entries that should otherwise be restricted.
The technical implementation of this flaw lies in how the rlogind service processes hosts.equiv entries when establishing remote connections. Normally, the rlogin protocol should respect the documented behavior where entries in the hosts.equiv file are only applied to the root account when explicitly configured to do so, and only from trusted hosts that have been properly authorized. However, this vulnerability causes the service to incorrectly apply hosts.equiv entries to the root account regardless of the configuration, effectively bypassing the intended access controls. The flaw likely stems from improper validation of host entries or incorrect handling of root account authentication logic within the rlogind daemon. This misconfiguration creates an attack surface where remote adversaries can exploit the service to establish privileged sessions without proper authentication, particularly when the hosts.equiv file contains entries that should only be applicable to non-root accounts or when the system is configured to trust specific hosts for root access. The vulnerability is particularly concerning because it operates at the authentication layer, meaning that successful exploitation could provide attackers with complete system control.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass potential complete system compromise and data exfiltration. Attackers exploiting this flaw could gain root privileges on affected Mac OS X systems, enabling them to modify system files, install malicious software, monitor network traffic, and access all user data without detection. The vulnerability affects systems that have the rlogin service enabled, which represents a legacy protocol that many administrators may have overlooked or disabled in favor of more secure SSH implementations. However, the presence of rlogin service on systems with proper configuration could create a backdoor that attackers can leverage for persistent access. The vulnerability also impacts system integrity by allowing unauthorized modifications to authentication parameters and could potentially serve as a foothold for further attacks within a network environment. Organizations relying on legacy systems or those that have not fully transitioned from rlogin to SSH implementations face significant risk from this vulnerability, as it undermines the fundamental security assumptions of host-based authentication.
Mitigation strategies for CVE-2008-4212 should focus on immediate service disablement and long-term security hardening measures. The most effective immediate action involves disabling the rlogin service entirely, as this protocol is inherently insecure and has been superseded by SSH implementations. System administrators should verify that the rlogin daemon is not running and that the service is disabled at the system level through appropriate configuration management tools. The hosts.equiv file should be carefully audited and restricted to only contain necessary entries, with any entries that could potentially allow root access from untrusted hosts removed or modified. Network segmentation and firewall rules should be implemented to prevent external access to the rlogin service ports, and comprehensive logging should be enabled to detect any attempted exploitation. Organizations should also conduct thorough vulnerability assessments to identify any other systems running legacy authentication services that may be similarly vulnerable. This vulnerability aligns with CWE-284 Access Control Issues, specifically focusing on improper access control mechanisms that allow unauthorized privilege escalation. From an ATT&CK perspective, this vulnerability maps to T1078 Valid Accounts and T1562 Impair Defenses, as it enables attackers to establish persistent access through legitimate authentication mechanisms while potentially bypassing security controls. The vulnerability also demonstrates characteristics of T1110 Credential Access, as it can be exploited to gain privileged access without proper authentication, and T1068 Exploitation for Privilege Escalation, since it directly enables privilege escalation from regular user to root access.