CVE-2023-21948: Oracle Solaris Privilege Escalation Flaw

CVE-2023-21948 Overview

CVE-2023-21948 is a privilege escalation vulnerability in the Oracle Solaris product of Oracle Systems, specifically affecting the Core component. This vulnerability allows a low-privileged attacker with local logon access to the infrastructure where Oracle Solaris executes to fully compromise the affected system.

The vulnerability is classified as easily exploitable, requiring only low privileges and no user interaction to execute successfully. An attacker who exploits this vulnerability could achieve complete takeover of the Oracle Solaris system, resulting in unauthorized access to sensitive data, system modification capabilities, and potential service disruption.

Critical Impact

Successful exploitation enables complete system takeover of Oracle Solaris 10, affecting confidentiality, integrity, and availability of the compromised host.

Affected Products

• Oracle Solaris 10 (all configurations)
• Oracle Systems utilizing Solaris 10 Core component
• Infrastructure environments running Oracle Solaris 10

Discovery Timeline

• April 18, 2023 - CVE-2023-21948 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2023-21948

Vulnerability Analysis

This vulnerability resides in the Core component of Oracle Solaris 10, representing a local privilege escalation attack surface. The flaw enables attackers who have already obtained low-privileged access to the system to escalate their privileges and achieve complete control over the affected Oracle Solaris installation.

The attack requires local access to the infrastructure, meaning an attacker must first establish a foothold on the target system through legitimate credentials or other means. Once local access is obtained, the vulnerability can be exploited with low complexity, making it particularly dangerous in environments where multiple users have logon access to Solaris systems.

Root Cause

While Oracle has not disclosed specific technical details about the root cause (classified as NVD-CWE-noinfo), the vulnerability characteristics suggest an issue within the Core component's privilege handling mechanisms. The local attack vector combined with the ability to achieve full system compromise indicates potential weaknesses in access control enforcement, privilege boundary validation, or system call handling within the Solaris kernel or core system utilities.

Attack Vector

The attack vector for CVE-2023-21948 requires local access to the affected Oracle Solaris 10 system. The exploitation process involves:

1. Initial Access - Attacker obtains low-privileged user access to the Oracle Solaris 10 system
2. Vulnerability Trigger - Attacker interacts with the vulnerable Core component functionality
3. Privilege Escalation - Exploitation allows the attacker to bypass privilege restrictions
4. System Takeover - Successful exploitation grants full administrative control over the system

The vulnerability does not require user interaction and has low attack complexity once local access is established, making it an attractive target for attackers who have compromised user accounts or gained initial access through other means.

Detection Methods for CVE-2023-21948

Indicators of Compromise

• Unexpected privilege escalation events in system audit logs showing users gaining root or administrative access
• Anomalous process execution patterns from low-privileged user accounts attempting to access protected system resources
• Unusual system call activity related to Core component functions
• Unauthorized modifications to system files or configurations that require elevated privileges

Detection Strategies

• Enable and monitor Solaris Basic Security Module (BSM) auditing for privilege escalation attempts
• Implement file integrity monitoring on critical system binaries and configuration files
• Deploy endpoint detection solutions capable of monitoring local privilege escalation patterns
• Configure alerting for unexpected su or sudo usage patterns and failed authentication attempts

Monitoring Recommendations

• Review system logs regularly for unauthorized administrative actions or unexpected user privilege changes
• Monitor process execution chains for anomalous parent-child relationships indicating exploitation
• Implement baseline monitoring for Core component interactions and alert on deviations
• Enable comprehensive logging of authentication events and privilege changes on all Solaris 10 systems

How to Mitigate CVE-2023-21948

Immediate Actions Required

• Apply the Oracle Critical Patch Update from April 2023 immediately on all affected Oracle Solaris 10 systems
• Audit all user accounts with local logon access to Solaris 10 systems and remove unnecessary access
• Implement strict access controls limiting which users can log on to affected infrastructure
• Increase monitoring and logging on systems that cannot be immediately patched

Patch Information

Oracle has addressed this vulnerability in the April 2023 Critical Patch Update. System administrators should obtain and apply the appropriate patches for Oracle Solaris 10 from My Oracle Support (MOS). The patch addresses the privilege escalation vulnerability in the Core component and should be applied as part of regular patch management cycles.

It is recommended to review the complete Critical Patch Update Advisory for any additional patches or configuration changes that may be required in conjunction with the primary fix.

Workarounds

• Restrict local logon access to Oracle Solaris 10 systems to only essential personnel and service accounts
• Implement network segmentation to limit lateral movement opportunities for attackers who may exploit this vulnerability
• Enable additional auditing and logging to detect exploitation attempts while awaiting patch deployment
• Consider migrating critical workloads to supported Oracle Solaris versions if Solaris 10 systems cannot be adequately secured

# Enable enhanced auditing on Oracle Solaris 10
# Configure BSM auditing to monitor privilege escalation attempts
auditconfig -setflags lo,ad,ex
auditconfig -setpolicy +argv,+arge
audit -s

# Restrict user access - review and limit logon privileges
# List current user access
logins -p

# Review system audit logs for suspicious activity
praudit /var/audit/*