CVE-2025-27898: IBM DB2 Recovery Expert Auth Bypass Flaw

CVE-2025-27898 Overview

IBM DB2 Recovery Expert for LUW 5.5 Interim Fix 002 contains a session management vulnerability where sessions are not properly invalidated after a timeout period. This weakness allows an authenticated user to potentially impersonate another user on the system, leading to unauthorized access to data and functionality.

Critical Impact

Authenticated attackers can exploit improper session timeout handling to impersonate other users, potentially accessing sensitive database recovery operations and confidential data.

Affected Products

• IBM DB2 Recovery Expert for LUW 5.5 Interim Fix 002

Discovery Timeline

• 2026-02-17 - CVE-2025-27898 published to NVD
• 2026-02-18 - Last updated in NVD database

Technical Details for CVE-2025-27898

Vulnerability Analysis

This vulnerability is classified under CWE-613 (Insufficient Session Expiration), which occurs when a web application permits an attacker to reuse old session credentials or session IDs for authorization. In the case of IBM DB2 Recovery Expert for LUW, the application fails to properly invalidate user sessions after the configured timeout period has elapsed.

When a session is not properly invalidated after timeout, the session token or identifier remains valid on the server side. An attacker who has obtained a valid session identifier (through various means such as network sniffing, session fixation, or accessing a shared system) can continue to use that session even after the legitimate user believes their session has ended.

The vulnerability allows exploitation over the network without requiring user interaction, though the attacker must have low-level privileges (authenticated access) to exploit the issue. Successful exploitation can result in limited impact to confidentiality, integrity, and availability of the system.

Root Cause

The root cause of CVE-2025-27898 lies in the improper implementation of session lifecycle management within IBM DB2 Recovery Expert for LUW. The application does not enforce server-side session invalidation when the session timeout threshold is reached. This means that even though a user's session may appear to be expired on the client side, the session credentials remain valid on the server, allowing continued authentication with the old session token.

Attack Vector

The attack can be executed over the network by an authenticated user. The attacker would need to:

1. Obtain a valid session identifier from a target user's session (through network interception, browser history, shared workstation access, or other session hijacking techniques)
2. Wait for or trigger the session timeout condition
3. Continue using the session identifier after the timeout period
4. Impersonate the original user and perform actions on their behalf within the DB2 Recovery Expert interface

The attack does not require the original user to be actively using the system at the time of exploitation, as the session token remains valid regardless of the timeout status.

Detection Methods for CVE-2025-27898

Indicators of Compromise

• Multiple authentication events from the same session ID after extended periods of inactivity
• Session tokens being used from different IP addresses or user agents within short time frames
• Unusual access patterns to DB2 Recovery Expert administrative functions outside normal business hours
• Log entries showing session activity continuing beyond configured timeout thresholds

Detection Strategies

• Implement session analytics to identify sessions that remain active beyond configured timeout periods
• Monitor for session ID reuse patterns that indicate potential session hijacking attempts
• Configure alerting for authentication anomalies such as impossible travel scenarios or simultaneous sessions from different locations
• Review IBM DB2 Recovery Expert access logs for unauthorized operations performed under compromised user contexts

Monitoring Recommendations

• Enable comprehensive session logging within IBM DB2 Recovery Expert for LUW to capture session creation, activity, and termination events
• Deploy network-level monitoring to detect session token transmission in clear text or suspicious session reuse patterns
• Establish baseline user behavior profiles and alert on deviations that may indicate session impersonation
• Integrate IBM DB2 Recovery Expert logs with SIEM solutions for centralized analysis and correlation

How to Mitigate CVE-2025-27898

Immediate Actions Required

• Apply the latest security patches from IBM for DB2 Recovery Expert for LUW as referenced in the IBM Support Page
• Review and reduce session timeout values to minimize the window of exploitation
• Force re-authentication for sensitive operations within the DB2 Recovery Expert interface
• Audit current user sessions and terminate any suspicious or long-running sessions

Patch Information

IBM has released security guidance addressing this vulnerability. Administrators should consult the official IBM Support Page for detailed patching instructions, updated software versions, and specific remediation steps for IBM DB2 Recovery Expert for LUW 5.5.

Organizations should prioritize applying the patch, particularly in environments where DB2 Recovery Expert is accessible over the network or where multiple users share access to the system.

Workarounds

• Implement network-level access controls to restrict access to IBM DB2 Recovery Expert to trusted IP addresses only
• Enable additional authentication factors (MFA) where supported to reduce the impact of session hijacking
• Configure shorter session timeout values and enforce mandatory re-authentication after periods of inactivity
• Deploy web application firewalls (WAF) with session management capabilities to detect and block anomalous session behavior
• Ensure all communications with DB2 Recovery Expert occur over encrypted channels (HTTPS/TLS) to prevent session token interception

Organizations should implement network segmentation to limit exposure of the DB2 Recovery Expert interface and ensure that session management best practices are followed until the official patch can be applied. Regular session audits and user access reviews can help identify potential exploitation attempts.