CVE-2025-36238 Overview
CVE-2025-36238 is an information disclosure vulnerability affecting IBM PowerVM Hypervisor across multiple firmware versions. The vulnerability allows a local user with administrative privileges to obtain sensitive information from a Virtual Trusted Platform Module (vTPM) through a series of PowerVM service procedures. This exposure of system information (CWE-497) could compromise the confidentiality of cryptographic keys and other sensitive data stored within the vTPM.
Critical Impact
Local administrators can extract sensitive vTPM data, potentially exposing cryptographic keys, attestation secrets, and other protected information managed by the Virtual TPM.
Affected Products
- IBM PowerVM Hypervisor FW1110.00 through FW1110.03
- IBM PowerVM Hypervisor FW1060.00 through FW1060.51
- IBM PowerVM Hypervisor FW950.00 through FW950.F0
Discovery Timeline
- 2026-02-02 - CVE CVE-2025-36238 published to NVD
- 2026-02-03 - Last updated in NVD database
Technical Details for CVE-2025-36238
Vulnerability Analysis
This vulnerability represents an information exposure issue within the IBM PowerVM Hypervisor's Virtual TPM implementation. The Virtual TPM is a critical security component that provides hardware-based security functions to guest partitions, including secure key storage, cryptographic operations, and platform attestation.
The vulnerability exists in the handling of PowerVM service procedures, which are administrative operations used for system management and maintenance. When an authenticated administrator executes a specific sequence of these service procedures, the hypervisor fails to properly protect sensitive vTPM data, allowing the information to be extracted.
The attack requires local access and high privileges (administrative rights), which limits the attack surface. However, the scope extends beyond the vulnerable component—the changed scope indicates that a compromised hypervisor can affect resources in guest partitions that rely on the vTPM for security. The impact is purely on confidentiality, with no direct integrity or availability concerns.
Root Cause
The root cause is classified as CWE-497: Exposure of Sensitive System Information to an Unauthorized Control Sphere. The PowerVM service procedures do not implement adequate access controls or data sanitization when handling vTPM-related operations. This allows privileged users to access information that should remain protected even from administrative accounts, violating the principle of least privilege for sensitive cryptographic material.
Attack Vector
The attack requires local access to the PowerVM environment with administrative privileges. An attacker would need to:
- Gain authenticated access to the Hardware Management Console (HMC) or equivalent management interface
- Possess administrative privileges on the target managed system
- Execute a specific sequence of PowerVM service procedures
- Extract the exposed vTPM data from the procedure outputs
The vulnerability cannot be exploited remotely without first compromising administrative credentials. The attack does not require user interaction beyond the attacker's own actions.
Technical details regarding the specific service procedures involved are available in the IBM Support Page.
Detection Methods for CVE-2025-36238
Indicators of Compromise
- Unusual or repeated execution of PowerVM service procedures targeting vTPM components
- Administrative access patterns that deviate from normal operational baselines
- Unexpected queries or data extraction from Virtual TPM subsystems
- Anomalous HMC session activity from administrative accounts
Detection Strategies
- Monitor HMC audit logs for service procedure executions, particularly those related to vTPM operations
- Implement behavioral analysis for administrative accounts to detect unusual command sequences
- Review PowerVM system logs for atypical vTPM access patterns
- Correlate administrative session timing with known maintenance windows
Monitoring Recommendations
- Enable comprehensive logging for all PowerVM service procedure invocations
- Configure alerting for vTPM-related administrative operations outside scheduled maintenance
- Implement privileged access management (PAM) solutions to track and audit administrative sessions
- Establish baselines for normal administrative activity to identify anomalous behavior
How to Mitigate CVE-2025-36238
Immediate Actions Required
- Review and restrict administrative access to PowerVM systems to only essential personnel
- Audit current administrative accounts for necessity and appropriate privilege levels
- Apply firmware updates from IBM as they become available
- Implement additional monitoring for vTPM-related service procedures
Patch Information
IBM has released security advisories addressing this vulnerability. Administrators should consult the IBM Support Page for detailed patching instructions and updated firmware versions. Apply the latest firmware updates for affected PowerVM Hypervisor versions:
- FW1110.xx series: Update to the latest available firmware beyond FW1110.03
- FW1060.xx series: Update to the latest available firmware beyond FW1060.51
- FW950.xx series: Update to the latest available firmware beyond FW950.F0
Workarounds
- Implement strict role-based access controls limiting who can execute PowerVM service procedures
- Enable comprehensive audit logging for all administrative actions on the HMC
- Segment management networks to restrict access to PowerVM administrative interfaces
- Consider implementing additional authentication factors for privileged operations
# Example: Review HMC audit logs for service procedure activity
# Consult IBM documentation for specific log locations and formats
# Enable enhanced logging via HMC management interface
# Review administrative user accounts and permissions regularly
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
