CVE-2023-40375: IBM i Privilege Escalation Vulnerability

CVE-2023-40375 Overview

CVE-2023-40375 is a local privilege escalation vulnerability affecting the Integrated Application Server component within IBM i operating system versions 7.2, 7.3, 7.4, and 7.5. This vulnerability allows a malicious actor with command line access to the host operating system to escalate privileges and gain root access, potentially compromising the entire system.

Critical Impact

A local attacker with limited privileges can exploit this vulnerability to obtain root-level access to the IBM i host operating system, enabling complete system compromise including access to sensitive data, system configuration modifications, and potential lateral movement within enterprise environments.

Affected Products

• IBM i 7.2
• IBM i 7.3
• IBM i 7.4
• IBM i 7.5

Discovery Timeline

• September 28, 2023 - CVE-2023-40375 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2023-40375

Vulnerability Analysis

This vulnerability falls under CWE-269 (Improper Privilege Management), indicating that the Integrated Application Server component fails to properly manage privilege levels during certain operations. The flaw resides in the local attack surface, requiring the attacker to have existing command line access to the host operating system.

The vulnerability enables a complete compromise of confidentiality, integrity, and availability of the affected system. Once exploited, an attacker transitions from a low-privileged user context to full root access, effectively bypassing all privilege boundaries intended to protect the system.

Root Cause

The root cause of CVE-2023-40375 stems from improper privilege management within the Integrated Application Server component. The application fails to adequately validate or restrict privilege transitions, allowing authenticated local users to escalate their privileges beyond their intended authorization level. This type of vulnerability typically occurs when privileged operations are not properly protected or when privilege checks can be circumvented through specific sequences of operations.

Attack Vector

The attack vector for this vulnerability is local, meaning an attacker must first obtain command line access to the IBM i host system. This could be achieved through:

• Compromised user credentials
• Insider threat scenarios
• Pivot from another compromised system on the network
• Physical access to the system

Once local access is established, the attacker can leverage the privilege escalation flaw to elevate their access from a standard user to root privileges. The attack requires low privilege levels to initiate and does not require user interaction, making it relatively straightforward to exploit once initial access is obtained.

The vulnerability mechanism involves exploiting improper privilege management in the Integrated Application Server component. Technical details regarding the specific exploitation method can be found in the IBM Support Document and IBM X-Force Vulnerability Report.

Detection Methods for CVE-2023-40375

Indicators of Compromise

• Unexpected privilege escalation events in system audit logs involving the Integrated Application Server
• Anomalous root-level processes spawned from low-privileged user sessions
• Unauthorized modifications to system configuration files or security policies
• Suspicious command line activity from user accounts not typically associated with administrative functions

Detection Strategies

• Enable comprehensive auditing on IBM i systems to capture privilege escalation attempts and monitor for unusual access patterns
• Implement file integrity monitoring on critical system binaries and configuration files
• Deploy endpoint detection and response (EDR) solutions capable of detecting privilege escalation behaviors on IBM i platforms
• Review authentication logs for accounts with recent successful authentications followed by elevated privilege operations

Monitoring Recommendations

• Configure SIEM rules to alert on privilege escalation patterns involving the Integrated Application Server component
• Establish baseline user behavior profiles and alert on deviations, particularly for command line activities
• Monitor for unauthorized changes to user privilege levels and group memberships
• Implement real-time alerting for root-level process creation from non-administrative user contexts

How to Mitigate CVE-2023-40375

Immediate Actions Required

• Apply the security patches provided by IBM for affected IBM i versions immediately
• Restrict command line access to the IBM i host operating system to only essential personnel
• Implement the principle of least privilege across all user accounts
• Conduct an audit of current user privileges to identify any existing unauthorized elevations

Patch Information

IBM has released security patches to address CVE-2023-40375 for all affected versions of IBM i (7.2, 7.3, 7.4, and 7.5). Organizations should consult the IBM Support Document #7038748 for detailed patching instructions and download links specific to their IBM i version. The IBM X-Force ID associated with this vulnerability is 263580.

Workarounds

• Limit command line access to the IBM i system to only authorized administrators until patches can be applied
• Implement network segmentation to restrict access to IBM i systems from untrusted network zones
• Enable enhanced auditing and monitoring to detect exploitation attempts before patches are deployed
• Consider implementing additional access controls such as multi-factor authentication for system access

# Configuration example - Restrict user access to command line
# Consult IBM documentation for proper implementation on your specific version
# Review and restrict QPWDEXPITV system value for password expiration
# Enable auditing with CHGSECAUD command to capture privilege changes
# Limit access to QSYS library and critical system objects