CVE-2025-4676: ABB WebPro SNMP Card Auth Bypass Flaw

CVE-2025-4676 Overview

CVE-2025-4676 is an Incorrect Implementation of Authentication Algorithm vulnerability affecting ABB WebPro SNMP Card PowerValue and ABB WebPro SNMP Card PowerValue UL devices. This vulnerability arises from improper implementation of authentication mechanisms, potentially allowing attackers on an adjacent network to bypass security controls and impact the confidentiality, integrity, and availability of downstream systems.

Critical Impact

This authentication algorithm implementation flaw affects industrial SNMP management cards used in power systems, potentially enabling unauthorized access to critical infrastructure components when exploited from an adjacent network.

Affected Products

• ABB WebPro SNMP Card PowerValue through version 1.1.8.K
• ABB WebPro SNMP Card PowerValue UL through version 1.1.8.K

Discovery Timeline

• 2026-01-07 - CVE CVE-2025-4676 published to NVD
• 2026-01-08 - Last updated in NVD database

Technical Details for CVE-2025-4676

Vulnerability Analysis

This vulnerability is classified under CWE-303 (Incorrect Implementation of Authentication Algorithm), indicating that the authentication mechanism in the affected ABB WebPro SNMP Card products does not properly validate user credentials or authentication tokens. The flaw requires the attacker to be on an adjacent network and some user interaction to successfully exploit, but can result in significant downstream impact including high confidentiality, integrity, and availability compromise of connected systems.

The authentication implementation fails to properly verify credentials, creating a pathway for attackers to gain unauthorized access to SNMP management functionality. While the immediate victim system may not suffer direct confidentiality or integrity impacts, the vulnerability enables attackers to pivot and affect subsequent systems in the industrial environment with severe consequences.

Root Cause

The root cause stems from incorrect implementation of the authentication algorithm in the WebPro SNMP Card firmware. This type of vulnerability typically occurs when developers implement custom authentication logic that fails to properly validate all aspects of the authentication process, such as credential verification, session token validation, or cryptographic operations. The flawed implementation allows attackers to circumvent intended authentication controls.

Attack Vector

The attack vector requires adjacent network access (meaning the attacker must be on the same network segment or have local network proximity to the target device). User interaction is required for successful exploitation. Once exploited, while the vulnerable system itself may not be directly compromised in terms of data confidentiality or integrity, the attacker gains the ability to severely impact downstream systems connected to or managed through the SNMP card, potentially affecting industrial control system operations.

The exploitation scenario involves an attacker on the adjacent network leveraging the authentication flaw to gain unauthorized access to the SNMP management interface. From this position, the attacker could manipulate configurations, disrupt monitoring capabilities, or use the compromised device as a pivot point for further attacks against connected power management infrastructure.

Detection Methods for CVE-2025-4676

Indicators of Compromise

• Unusual authentication attempts or failed login patterns on WebPro SNMP Card management interfaces
• Unexpected configuration changes on SNMP card devices without corresponding administrative activity
• Anomalous SNMP traffic patterns from devices on the local network segment
• Unauthorized sessions or connections to the WebPro management interface

Detection Strategies

• Monitor network traffic for suspicious authentication requests to ABB WebPro SNMP Card devices from unexpected sources
• Implement network segmentation monitoring to detect lateral movement attempts from compromised SNMP cards
• Deploy intrusion detection rules to identify exploitation attempts targeting authentication mechanisms on industrial devices
• Audit authentication logs on WebPro SNMP Card devices for anomalies

Monitoring Recommendations

• Enable comprehensive logging on all ABB WebPro SNMP Card devices and centralize log collection
• Implement network behavior analysis for adjacent network segments containing vulnerable devices
• Configure alerts for any administrative access to SNMP card management interfaces outside of maintenance windows
• Regularly review device configurations for unauthorized changes

How to Mitigate CVE-2025-4676

Immediate Actions Required

• Identify all ABB WebPro SNMP Card PowerValue and PowerValue UL devices running firmware version 1.1.8.K or earlier in your environment
• Implement network segmentation to isolate vulnerable SNMP card devices from untrusted network segments
• Restrict adjacent network access to only authorized management systems
• Monitor for any suspicious activity targeting these devices while awaiting official patches

Patch Information

ABB has published a security advisory addressing this vulnerability. Organizations should consult the ABB Security Advisory for detailed remediation guidance and firmware update information. Apply vendor-supplied patches as soon as they become available for your specific device models.

Workarounds

• Implement strict network segmentation to limit adjacent network access to vulnerable devices
• Deploy additional authentication controls such as VPN or jump hosts for accessing SNMP card management interfaces
• Disable unnecessary network services on the SNMP cards where possible to reduce attack surface
• Implement allowlisting for IP addresses permitted to communicate with the device management interface

# Network segmentation example - restrict access to SNMP management VLAN
# Ensure vulnerable devices are isolated on dedicated management network
# Example iptables rule to restrict adjacent network access
iptables -A INPUT -i eth0 -s 192.168.100.0/24 -d 192.168.100.50 -p tcp --dport 161 -j ACCEPT
iptables -A INPUT -i eth0 -d 192.168.100.50 -p tcp --dport 161 -j DROP