CVE-2025-7741: CENTUM VP Auth Bypass Vulnerability

CVE-2025-7741 Overview

A hardcoded password vulnerability has been discovered in Yokogawa CENTUM industrial control systems. The affected products contain a hardcoded password for the user account (PROG) used for CENTUM Authentication Mode within the system. Under specific conditions, an attacker could leverage this vulnerability to log in as the PROG user.

The default permission for the PROG user is S1 permission (equivalent to OFFUSER). Therefore, for properly permission-controlled targets of operation and monitoring, even if an attacker logs in as the PROG user, the risk of critical operations or configuration changes being performed is considered low. However, if the PROG user's permissions have been modified, there is a risk that operations or configuration changes may be performed under those elevated permissions.

Critical Impact

Attackers who obtain the hardcoded password and have access to the HIS screen controls could potentially authenticate as the PROG user, bypassing normal authentication mechanisms in industrial control system environments.

Affected Products

• CENTUM VP R5.01.00 to R5.04.20
• CENTUM VP R6.01.00 to R6.12.00
• CENTUM VP R7.01.00

Discovery Timeline

• 2026-03-30 - CVE CVE-2025-7741 published to NVD
• 2026-03-30 - Last updated in NVD database

Technical Details for CVE-2025-7741

Vulnerability Analysis

This vulnerability is classified as CWE-259 (Use of Hard-coded Password), a configuration flaw that poses security risks in industrial control system environments. The hardcoded credentials exist within the CENTUM system for the PROG user account, which is used for CENTUM Authentication Mode (CTM).

The exploitation of this vulnerability requires multiple preconditions to be met simultaneously: the attacker must first obtain the hardcoded password through some method, the Human Interface Station (HIS) must be configured in CTM authentication mode, and the attacker must have direct access to the HIS or the ability to remotely access and perform screen operations.

The local attack vector with high complexity requirements significantly limits the practical exploitability of this vulnerability. Additionally, since PROG users have S1 permissions by default (equivalent to OFFUSER), successful exploitation with default configurations provides limited operational capabilities.

Root Cause

The root cause of this vulnerability is the use of hardcoded credentials within the CENTUM software. The PROG user account password is embedded directly in the system, creating a static credential that cannot be changed through normal configuration methods. This represents a fundamental design flaw where security credentials are not properly managed through secure credential storage mechanisms.

Attack Vector

Exploitation of CVE-2025-7741 requires a local attack vector with multiple prerequisites:

1. The attacker must first discover or obtain the hardcoded PROG user password through reverse engineering, memory analysis, or other extraction methods
2. The target HIS must be configured to use CENTUM Authentication Mode (CTM)
3. The attacker must have physical or remote access to the HIS and be able to interact with screen controls
4. The attacker must be in a position to enter authentication credentials

Given these requirements, the attack complexity is high. The vulnerability does not enable remote code execution directly but could allow unauthorized authentication to the industrial control system interface.

Detection Methods for CVE-2025-7741

Indicators of Compromise

• Unexpected authentication attempts or successful logins using the PROG user account
• Authentication events from the PROG account during unusual hours or from unexpected locations
• Multiple failed authentication attempts followed by successful PROG user login
• PROG user account activity inconsistent with normal operational patterns

Detection Strategies

• Monitor authentication logs for PROG user account access, particularly in environments where this account is not normally used
• Implement alerting for any authentication attempts using the PROG user credentials
• Deploy network monitoring to detect unauthorized access attempts to HIS systems
• Review audit logs for configuration changes or operations performed under the PROG user context

Monitoring Recommendations

• Enable comprehensive logging for all authentication events on CENTUM HIS systems
• Implement real-time alerting for PROG user authentication events
• Conduct regular reviews of user activity logs for anomalous patterns
• Monitor network traffic to HIS systems for unauthorized access attempts

How to Mitigate CVE-2025-7741

Immediate Actions Required

• Review the Yokogawa Security Advisory YSAR-26-0003 for vendor-specific remediation guidance
• Verify that PROG user permissions have not been elevated above the default S1 (OFFUSER) level
• Restrict physical and network access to HIS systems to authorized personnel only
• Implement network segmentation to isolate industrial control systems from general network access

Patch Information

Yokogawa has released a security advisory addressing this vulnerability. Organizations should consult the Yokogawa Security Advisory YSAR-26-0003 for detailed patch information and remediation steps specific to their CENTUM VP version.

Contact Yokogawa support for guidance on obtaining and applying security updates for affected CENTUM VP installations.

Workarounds

• Implement strict network access controls to limit connectivity to HIS systems
• Ensure PROG user permissions remain at the default S1 (OFFUSER) level
• Consider using alternative authentication modes if available and appropriate for your environment
• Deploy additional monitoring and intrusion detection capabilities around HIS systems
• Implement physical security measures to prevent unauthorized access to HIS workstations

# Network segmentation example for industrial control systems
# Restrict access to HIS systems to authorized management networks only
# Consult your network security team for environment-specific implementation
iptables -A INPUT -s 10.10.0.0/24 -p tcp --dport 443 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP