CVE-2025-40745: Siemens Products Auth Bypass Vulnerability

CVE-2025-40745 Overview

A certificate validation bypass vulnerability has been identified in multiple Siemens industrial software products. The affected applications do not properly validate client certificates when connecting to the Analytics Service endpoint. This improper certificate validation (CWE-295) could allow an unauthenticated remote attacker to perform man-in-the-middle (MitM) attacks, potentially intercepting or manipulating communications between the client applications and the Analytics Service.

Critical Impact

Unauthenticated remote attackers can intercept sensitive data or manipulate communications through man-in-the-middle attacks due to improper certificate validation in Siemens industrial software suite.

Affected Products

• Siemens Software Center (All versions < V3.5.8.2)
• Simcenter 3D (All versions < V2506.6000)
• Simcenter Femap (All versions < V2506.0002)
• Simcenter STAR-CCM+ (All versions < V2602)
• Solid Edge SE2025 (All versions < V225.0 Update 13)
• Solid Edge SE2026 (All versions < V226.0 Update 04)
• Tecnomatix Plant Simulation (All versions < V2504.0008)

Discovery Timeline

• 2026-04-14 - CVE-2025-40745 published to NVD
• 2026-04-14 - Last updated in NVD database

Technical Details for CVE-2025-40745

Vulnerability Analysis

This vulnerability stems from improper certificate validation (CWE-295) in how the affected Siemens applications handle client certificate verification when establishing connections to the Analytics Service endpoint. When an application fails to properly validate certificates, it creates an opportunity for attackers to position themselves between the client and server, intercepting or modifying traffic in transit.

The network-based attack vector allows remote exploitation without requiring authentication or user interaction, though the attack does require precise timing and network positioning to execute successfully. The primary impact is on confidentiality, as attackers could potentially intercept sensitive data transmitted between the industrial software applications and the Analytics Service.

Root Cause

The root cause of this vulnerability is the insufficient validation of client certificates during the TLS/SSL handshake process when connecting to the Analytics Service endpoint. The affected applications fail to perform adequate checks on certificate properties such as validity period, certificate chain trust, revocation status, or hostname verification. This oversight allows attackers with network access to present fraudulent certificates that the application will incorrectly accept as legitimate.

Attack Vector

The attack leverages the network accessibility of the Analytics Service connection. An attacker positioned on the same network segment or with the ability to intercept network traffic (such as through ARP spoofing, DNS hijacking, or compromised network infrastructure) can intercept connection attempts from the affected Siemens applications.

When a vulnerable application attempts to connect to the Analytics Service, the attacker can present their own certificate to establish separate encrypted sessions with both the client and the legitimate server. Since the application does not properly validate certificates, it accepts the attacker's certificate without raising security warnings, enabling full interception and potential modification of transmitted data.

The vulnerability mechanism involves the following flow:

1. The affected Siemens application initiates a connection to the Analytics Service endpoint
2. An attacker intercepts the connection request before it reaches the legitimate server
3. The attacker presents a fraudulent certificate to the client application
4. Due to improper validation, the application accepts the invalid certificate
5. The attacker establishes a separate connection to the legitimate Analytics Service
6. All traffic flows through the attacker, who can read and modify data in transit

For detailed technical information, refer to the Siemens Security Advisory SSA-981622.

Detection Methods for CVE-2025-40745

Indicators of Compromise

• Unexpected certificate warnings or errors in application logs related to Analytics Service connections
• Network traffic analysis showing certificate fingerprints that do not match known legitimate Siemens Analytics Service certificates
• Detection of ARP spoofing or DNS hijacking attempts targeting workstations running affected Siemens software
• Anomalous SSL/TLS connection patterns or certificate chains in network monitoring tools

Detection Strategies

• Implement network-based SSL/TLS inspection to monitor certificate exchanges during Analytics Service connections
• Deploy intrusion detection systems (IDS) with rules to detect man-in-the-middle attack patterns and certificate anomalies
• Monitor application logs for certificate validation errors or connection failures to Analytics Service endpoints
• Use endpoint detection and response (EDR) solutions to identify suspicious network interception behavior

Monitoring Recommendations

• Enable verbose logging for certificate validation events in affected Siemens applications where supported
• Implement certificate pinning monitoring to detect when unexpected certificates are presented by Analytics Service connections
• Configure network monitoring tools to alert on certificate authority mismatches for known Siemens service endpoints
• Establish baseline network behavior for Analytics Service communications to identify deviations

How to Mitigate CVE-2025-40745

Immediate Actions Required

• Upgrade all affected Siemens applications to the patched versions listed in the security advisory
• Implement network segmentation to isolate workstations running affected software from untrusted network segments
• Enable certificate pinning or strict certificate validation at the network level where possible
• Audit network infrastructure for signs of compromise or unauthorized devices that could facilitate MitM attacks

Patch Information

Siemens has released security updates to address this vulnerability. Organizations should upgrade to the following minimum versions:

• Siemens Software Center: V3.5.8.2 or later
• Simcenter 3D: V2506.6000 or later
• Simcenter Femap: V2506.0002 or later
• Simcenter STAR-CCM+: V2602 or later
• Solid Edge SE2025: V225.0 Update 13 or later
• Solid Edge SE2026: V226.0 Update 04 or later
• Tecnomatix Plant Simulation: V2504.0008 or later

For complete patch details and download links, refer to the Siemens Security Advisory SSA-981622.

Workarounds

• Restrict network access to the Analytics Service endpoint to trusted network segments only until patches can be applied
• Implement network-level certificate validation using a TLS-terminating proxy with proper certificate verification
• Consider temporarily disabling Analytics Service connectivity in affected applications if the feature is not critical to operations
• Deploy network monitoring and intrusion prevention systems to detect and block potential MitM attack attempts

# Example: Network segmentation firewall rule to restrict Analytics Service access
# Restrict outbound connections from affected software to known Siemens Analytics Service IPs only
# Consult Siemens documentation for current Analytics Service IP ranges

# iptables example (Linux-based firewall)
iptables -A OUTPUT -p tcp --dport 443 -d analytics.siemens.com -j ACCEPT
iptables -A OUTPUT -p tcp --dport 443 -m owner --uid-owner siemens_user -j DROP