CVE-2008-5690 in OpenSolaris
Summary
by MITRE
The Kerberos credential renewal feature in Sun Solaris 8, 9, and 10, and OpenSolaris build snv_01 through snv_104, allows local users to cause a denial of service (authentication failure) via unspecified vectors related to incorrect cache file permissions, and lack of credential storage by the store_cred function in pam_krb5.
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Analysis
by VulDB Data Team • 08/21/2019
The vulnerability identified as CVE-2008-5690 represents a critical flaw in the Kerberos authentication mechanism within Sun Solaris operating systems spanning versions 8 through 10 and OpenSolaris builds snv_01 through snv_104. This issue specifically targets the credential renewal functionality that forms a fundamental component of the Kerberos authentication framework, which is widely deployed in enterprise environments for secure network authentication. The flaw manifests through improper handling of cache file permissions and inadequate credential storage mechanisms within the pam_krb5 module, creating a pathway for malicious actors to disrupt legitimate authentication processes.
The technical root cause of this vulnerability stems from the incorrect implementation of cache file permissions within the Kerberos credential renewal process. When the store_cred function in pam_krb5 fails to properly manage credential storage, it creates an environment where local users can manipulate cache files to trigger authentication failures. This misconfiguration allows attackers to exploit the system's credential handling mechanisms, particularly when the system attempts to renew Kerberos tickets through the pam_krb5 module. The vulnerability operates at the privilege level of local users, meaning that an attacker with minimal system access can potentially disrupt the entire authentication infrastructure.
The operational impact of CVE-2008-5690 extends beyond simple service disruption to create a comprehensive authentication failure scenario that can severely impact enterprise security operations. When the denial of service condition occurs, legitimate users attempting to authenticate to network services protected by Kerberos will experience repeated authentication failures, effectively locking them out of critical systems and applications. This vulnerability particularly affects environments where Kerberos is heavily relied upon for single sign-on functionality, enterprise application access, and secure remote connections. The disruption can cascade through interconnected systems that depend on Kerberos authentication, potentially causing widespread operational issues within the affected organization.
Security professionals should recognize this vulnerability as a classic example of improper privilege management and file permission handling, which aligns with CWE-276, representing improper file permissions. The attack pattern for this vulnerability follows the ATT&CK technique T1550.003 for Kerberoasting, though in this case the impact is more focused on authentication denial rather than credential harvesting. Organizations should implement immediate mitigations including verifying proper cache file permissions, ensuring the pam_krb5 module is properly configured, and applying the appropriate security patches released by Oracle for the affected Solaris versions. Additionally, monitoring for unauthorized access attempts to Kerberos cache files and implementing proper access controls for authentication-related system components can help detect and prevent exploitation of this vulnerability. The remediation process should include comprehensive system auditing to verify that credential storage mechanisms function correctly and that no unauthorized modifications have occurred to the Kerberos authentication infrastructure.