CVE-2023-45168: IBM VIOS RCE Vulnerability

CVE-2023-45168 Overview

CVE-2023-45168 is a command injection vulnerability affecting IBM AIX 7.2, 7.3, and VIOS 3.1 that allows a non-privileged local user to exploit a flaw in the invscout command to execute arbitrary commands on the system. This vulnerability enables local privilege escalation, potentially allowing attackers to gain elevated access to critical enterprise AIX systems.

Critical Impact

Local attackers with low-level access can execute arbitrary commands through the vulnerable invscout utility, potentially leading to complete system compromise on IBM AIX and VIOS environments.

Affected Products

• IBM AIX 7.2
• IBM AIX 7.3
• IBM VIOS 3.1

Discovery Timeline

• 2023-12-01 - CVE-2023-45168 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2023-45168

Vulnerability Analysis

This vulnerability exists in the invscout command, a system utility used in IBM AIX and VIOS environments for inventory management and system discovery operations. The core issue stems from improper handling of user-supplied input, which allows a local attacker to inject and execute arbitrary commands with the privileges of the invscout process.

The vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), suggesting that the command injection may be facilitated through a buffer handling weakness that allows the attacker to manipulate execution flow. When exploited, an authenticated local user with limited privileges can leverage this flaw to escalate privileges and execute commands beyond their authorized scope.

Root Cause

The root cause of CVE-2023-45168 lies in insufficient input validation within the invscout command implementation. The utility fails to properly sanitize user-controlled input before processing it in a context where command execution occurs. This allows specially crafted input to break out of the intended command structure and inject malicious commands.

The combination of improper bounds checking (CWE-119) and inadequate input sanitization creates a scenario where local users can abuse the trusted invscout command to achieve arbitrary command execution, bypassing the normal privilege boundaries enforced by the AIX operating system.

Attack Vector

The attack vector is local, requiring the attacker to have authenticated access to the target AIX or VIOS system. Once authenticated with even low-level privileges, the attacker can exploit the invscout command by providing malicious input that includes command injection payloads.

The exploitation mechanism involves crafting input that escapes the expected parameter context and introduces additional commands that are then executed by the system. Since invscout may run with elevated privileges or access sensitive system resources, successful exploitation can result in privilege escalation, unauthorized data access, or system compromise.

For detailed technical information, refer to the IBM Support Document #7086090 and the IBM X-Force Vulnerability #267966.

Detection Methods for CVE-2023-45168

Indicators of Compromise

• Unusual or unexpected execution of the invscout command by non-administrative users
• Process spawning anomalies where invscout launches unexpected child processes
• Audit log entries showing command injection patterns or shell metacharacters in invscout arguments
• Unexpected privilege escalation events correlated with invscout execution

Detection Strategies

• Monitor AIX audit logs for suspicious invscout command invocations with unusual parameters
• Implement process monitoring to detect invscout spawning unexpected child processes or shells
• Deploy file integrity monitoring on system binaries and configuration files that may be modified post-exploitation
• Correlate user activity logs with invscout execution patterns to identify anomalous behavior

Monitoring Recommendations

• Enable comprehensive auditing for the invscout command and related system utilities
• Configure real-time alerting for any invscout execution by non-administrative accounts
• Monitor for shell spawning events that follow invscout command execution
• Review and baseline normal invscout usage patterns to identify deviations

How to Mitigate CVE-2023-45168

Immediate Actions Required

• Apply the security patches provided by IBM for AIX 7.2, 7.3, and VIOS 3.1 immediately
• Restrict access to the invscout command to only authorized administrative users
• Audit current system access to identify users who may have exploited this vulnerability
• Review system logs for evidence of exploitation attempts

Patch Information

IBM has released security updates to address this vulnerability. Administrators should obtain and apply the appropriate patches from the IBM Support Document #7086090. The patches address the improper input handling in the invscout command to prevent command injection attacks.

It is critical to test patches in a non-production environment before deploying to production AIX and VIOS systems to ensure compatibility with existing configurations and workloads.

Workarounds

• Restrict execute permissions on the invscout binary to root and authorized administrative groups only
• Implement strict user access controls to limit which accounts can access the vulnerable command
• Consider temporarily disabling or removing the invscout command if it is not essential for operations until patching is complete
• Deploy enhanced monitoring and logging around the invscout utility to detect exploitation attempts

# Restrict invscout permissions as a temporary mitigation
chmod 700 /usr/bin/invscout
chown root:system /usr/bin/invscout

# Verify current permissions
ls -la /usr/bin/invscout

# Enable AIX auditing for command execution
audit start