---
title: "Siemens Gridscale X Prepay Vulnerabilities Expose Energy Systems to Attacks"
short_title: "Siemens Gridscale X Prepay security flaws exposed"
description: "Two critical vulnerabilities in Siemens Gridscale X Prepay could allow attackers to bypass authentication and enumerate user accounts. Learn mitigation steps now."
author: "Vitus"
date: 2025-01-24
categories: [Cybersecurity, Vulnerabilities]
tags: [siemens, cve-2025-40806, cve-2025-40807, authentication bypass, energy sector]
score: 0.75
cve_ids: [CVE-2025-40806, CVE-2025-40807]
---
TL;DR
Siemens Gridscale X Prepay, a critical energy management system, has been found vulnerable to two security flaws: CVE-2025-40806 (user enumeration) and CVE-2025-40807 (authentication bypass). Exploiting these vulnerabilities could allow attackers to compromise user sessions and gain unauthorized access. Siemens has released mitigations, and users are urged to apply them immediately.
---
Main Content
Critical Vulnerabilities in Siemens Gridscale X Prepay Threaten Energy Sector Security
The Cybersecurity and Infrastructure Security Agency (CISA) recently highlighted two critical vulnerabilities in Siemens Gridscale X Prepay, a widely used energy management system. These flaws, if exploited, could enable attackers to enumerate valid user accounts and bypass locked-out user sessions, posing significant risks to energy infrastructure worldwide. Siemens has issued advisories and mitigation steps to address these issues, but organizations must act swiftly to secure their systems.
---
Key Points
- Vulnerabilities Identified: Two flaws—CVE-2025-40806 (Observable Response Discrepancy) and CVE-2025-40807 (Authentication Bypass by Capture-Replay)—affect Siemens Gridscale X Prepay versions prior to 4.2.1.
- Exploitation Risk: Attackers can remotely exploit these vulnerabilities with low attack complexity, potentially gaining unauthorized access to critical energy management systems.
- Impact: Successful exploitation could lead to user enumeration, brute force attacks, and session hijacking, compromising the integrity of energy infrastructure.
- Mitigation: Siemens recommends contacting local representatives for patches and implementing network security best practices to reduce exposure.
---
Technical Details
#### Affected Products
- Siemens Gridscale X Prepay: All versions prior to 4.2.1 are vulnerable.
#### Vulnerability Breakdown
1. CVE-2025-40806: Observable Response Discrepancy (CWE-204)
- CVSS v4 Score: 6.9
- Description: The application responds differently to valid and invalid user inputs, allowing attackers to enumerate valid user accounts. This could facilitate brute force attacks using confirmed usernames.
- Impact: Unauthenticated remote attackers can determine valid users, increasing the risk of targeted attacks.
2. CVE-2025-40807: Authentication Bypass by Capture-Replay (CWE-294)
- CVSS v4 Score: 5.3
- Description: The application is vulnerable to capture-replay attacks, where authentication tokens can be reused even after a user has been locked out. This could allow attackers to bypass session restrictions and gain unauthorized access.
- Impact: Authenticated but locked-out users may still establish valid sessions, compromising system security.
---
Impact Assessment
The vulnerabilities in Siemens Gridscale X Prepay pose a high risk to the energy sector, a critical infrastructure industry. Exploitation could lead to:
- Unauthorized access to energy management systems.
- Disruption of services, potentially causing outages or operational failures.
- Increased attack surface for further cyber threats, including ransomware or data breaches.
Given the global deployment of Gridscale X Prepay, organizations must prioritize patching and securing their systems to prevent potential attacks.
---
Mitigation Steps
#### Siemens Recommendations
- Update to Version 4.2.1: Contact your local Siemens representative for patches and upgrade guidance.
- Network Security: Protect devices by restricting network access and isolating them from business networks.
- Operational Guidelines: Follow Siemens’ [operational guidelines for industrial security](https://www.siemens.com/cert/operational-guidelines-industrial-security) to harden systems.
#### CISA Recommendations
- Minimize Exposure: Ensure control system devices are not accessible from the internet.
- Firewalls: Locate control system networks behind firewalls and isolate them from business networks.
- Secure Remote Access: Use Virtual Private Networks (VPNs) for remote access, ensuring they are updated to the latest version.
- Defensive Measures: Implement [CISA’s recommended practices for industrial control systems (ICS)](https://www.cisa.gov/resources-tools/resources/ics-recommended-practices).
---
Conclusion
The discovery of CVE-2025-40806 and CVE-2025-40807 in Siemens Gridscale X Prepay underscores the critical importance of securing energy infrastructure against cyber threats. Organizations using affected versions must apply patches immediately and follow best practices to mitigate risks. As cyber threats evolve, proactive defense strategies are essential to safeguarding critical systems.
For more details, refer to the [Siemens ProductCERT Advisory](https://cert-portal.siemens.com/productcert/html/ssa-356310.html) and [CISA’s ICS Advisory](https://www.cisa.gov/news-events/ics-advisories/icsa-25-345-09).
---
References
[^1]: Siemens ProductCERT. "[SSA-356310: Vulnerabilities in Gridscale X Prepay](https://cert-portal.siemens.com/productcert/html/ssa-356310.html)". Retrieved 2025-01-24.
[^2]: CISA. "[ICS Advisory (ICSA-25-345-09): Siemens Gridscale X Prepay](https://www.cisa.gov/news-events/ics-advisories/icsa-25-345-09)". Retrieved 2025-01-24.
[^3]: MITRE. "[CWE-204: Observable Response Discrepancy](https://cwe.mitre.org/data/definitions/204.html)". Retrieved 2025-01-24.
[^4]: MITRE. "[CWE-294: Authentication Bypass by Capture-Replay](https://cwe.mitre.org/data/definitions/294.html)". Retrieved 2025-01-24.