CVE-2025-3495: Delta Electronics COMMGR RCE Vulnerability

CVE-2025-3495 Overview

CVE-2025-3495 is a critical authentication bypass vulnerability in Delta Electronics COMMGR v1 and v2 caused by insufficient randomization of session IDs (CWE-338). The vulnerability allows remote attackers to brute force session identifiers due to predictable random number generation, enabling unauthorized access to load and execute arbitrary code on affected systems.

Critical Impact

Remote attackers can bypass authentication by predicting session IDs, leading to arbitrary code execution on industrial control system components without requiring any user interaction or prior authentication.

Affected Products

• Delta Electronics COMMGR v1
• Delta Electronics COMMGR v2

Discovery Timeline

• April 16, 2025 - CVE-2025-3495 published to NVD
• April 16, 2025 - Last updated in NVD database

Technical Details for CVE-2025-3495

Vulnerability Analysis

This vulnerability stems from the use of a Pseudo-Random Number Generator (PRNG) with insufficient entropy in session ID generation (CWE-338). When session identifiers are generated using weak randomization, the resulting values become predictable, allowing attackers to enumerate or brute force valid session tokens.

Delta Electronics COMMGR, a communication management component used in industrial control system (ICS) environments, fails to implement cryptographically secure random number generation for session management. This design flaw enables remote attackers to systematically guess valid session IDs without authentication, effectively bypassing the application's access controls.

Upon successfully predicting a valid session ID, an attacker gains the ability to load and execute arbitrary code within the context of the compromised session. Given that COMMGR operates in industrial environments, successful exploitation could result in manipulation of industrial processes, unauthorized access to sensitive operational data, or disruption of critical infrastructure operations.

Root Cause

The root cause is the implementation of an insecure random number generator for session ID creation. Instead of using cryptographically secure pseudorandom number generators (CSPRNG), the application relies on predictable algorithms with insufficient entropy. This results in session IDs that follow discernible patterns or fall within a constrained value space, making brute force attacks computationally feasible.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker can remotely enumerate session IDs by sending requests to the COMMGR service and observing patterns in session token generation. The low attack complexity combined with high impact on confidentiality, integrity, and availability makes this a critical threat vector for exposed COMMGR installations.

The attack flow typically involves:

1. Identifying an exposed COMMGR service on the network
2. Analyzing session ID generation patterns through observation
3. Brute forcing valid session IDs using the identified pattern
4. Hijacking an authenticated session to execute arbitrary code

Detection Methods for CVE-2025-3495

Indicators of Compromise

• Unusual volume of session-related requests from single IP addresses attempting different session IDs
• Multiple failed authentication or session validation attempts in rapid succession
• Unexpected code execution or process spawning on systems running COMMGR
• Network traffic patterns indicating session enumeration or brute force attempts against COMMGR ports

Detection Strategies

• Monitor COMMGR service logs for abnormal session creation rates or validation failures
• Implement network intrusion detection rules to identify session ID brute force patterns
• Deploy behavioral analysis to detect unusual authentication bypass attempts targeting ICS components
• Correlate authentication events with subsequent code execution activities on COMMGR hosts

Monitoring Recommendations

• Enable verbose logging on COMMGR services to capture session management events
• Implement rate limiting alerts for session validation requests exceeding normal thresholds
• Monitor network traffic to/from COMMGR services for signs of enumeration activity
• Establish baseline behavior patterns for COMMGR to detect anomalous session activity

How to Mitigate CVE-2025-3495

Immediate Actions Required

• Restrict network access to COMMGR services using firewall rules and network segmentation
• Implement additional authentication layers or access controls in front of COMMGR services
• Monitor systems running COMMGR v1 and v2 for signs of exploitation
• Review the CISA ICS Advisory ICSA-25-105-07 for detailed mitigation guidance

Patch Information

Delta Electronics has released a security advisory addressing this vulnerability. Organizations should review the DeltaPCSA 2025-00005 Advisory for official patch information and upgrade instructions. Apply vendor-provided patches as soon as they become available for your COMMGR version.

Workarounds

• Isolate COMMGR services from untrusted networks and the internet using network segmentation
• Implement VPN or other secure access methods for remote connections to COMMGR
• Deploy web application firewalls or ICS security appliances to filter malicious session enumeration attempts
• Consider disabling remote access to COMMGR until patches can be applied in critical environments