---
title: "Siemens TeleControl Server Flaw Allows Local Privilege Escalation"
short_title: "Siemens TeleControl Server privilege escalation flaw"
description: "Siemens patches a high-severity privilege escalation vulnerability (CVE-2025-40942) in TeleControl Server Basic. Update now to secure critical infrastructure systems."
author: "Vitus"
date: 2025-01-24
categories: [Cybersecurity, Vulnerabilities]
tags: [siemens, cve-2025-40942, privilege-escalation, ics-security, critical-infrastructure]
score: 0.78
cve_ids: [CVE-2025-40942]
---
TL;DR
Siemens has released a critical security update for its TeleControl Server Basic software, addressing a local privilege escalation vulnerability (CVE-2025-40942). The flaw, rated 8.8 (High), could allow attackers to execute arbitrary code with elevated privileges. Organizations in energy, water, and transportation sectors must update to version V3.1.2.4 or later to mitigate risks.
---
Main Content
Introduction
Siemens has issued a security advisory to address a high-severity vulnerability in its TeleControl Server Basic software, a widely used solution for monitoring and controlling critical infrastructure systems. The flaw, tracked as CVE-2025-40942, enables local attackers to escalate privileges and execute arbitrary code with elevated permissions. Given the software's deployment in energy, water, and transportation sectors, this vulnerability poses significant risks to operational security.
---
Key Points
- Vulnerability: Local privilege escalation (CVE-2025-40942) in Siemens TeleControl Server Basic.
- Severity: Rated 8.8 (High) on the CVSS scale, with a vector of CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
- Affected Versions: All versions of TeleControl Server Basic prior to V3.1.2.4.
- Impact: Attackers can execute arbitrary code with elevated privileges, compromising critical infrastructure systems.
- Mitigation: Siemens recommends updating to V3.1.2.4 or later immediately.
---
Technical Details
The vulnerability stems from execution with unnecessary privileges (CWE-250) in the TeleControl Server Basic application. An attacker with local access to the system can exploit this flaw to run arbitrary code with elevated permissions. The CVSS 3.1 base score of 8.8 reflects the high potential impact on confidentiality, integrity, and availability of affected systems.
#### Affected Systems
- Product: Siemens TeleControl Server Basic
- Vendor: Siemens
- Affected Versions: All versions prior to V3.1.2.4
- Product Status: Known affected
---
Impact Assessment
The vulnerability poses a critical risk to organizations relying on Siemens TeleControl Server Basic for operational control in energy, water, and wastewater, and transportation systems. Successful exploitation could lead to:
- Unauthorized access to sensitive operational data.
- Disruption of critical services.
- Compromise of entire industrial control systems (ICS).
Given the global deployment of this software, the potential for widespread impact is significant, particularly in sectors where uptime and reliability are paramount.
---
Mitigation Steps
Siemens has released version V3.1.2.4 to address this vulnerability. Organizations are urged to:
1. Update Immediately: Apply the latest patch (V3.1.2.4 or later) to all affected systems.
2. Restrict Network Access: Protect devices with appropriate network security mechanisms.
3. Follow Operational Guidelines: Adhere to Siemens' [Industrial Security Guidelines](https://www.siemens.com/cert/operational-guidelines-industrial-security) for secure deployment.
4. Isolate Critical Systems: Locate control system networks behind firewalls and isolate them from business networks.
5. Use Secure Remote Access: Employ Virtual Private Networks (VPNs) for remote access, ensuring they are updated to the latest version.
---
Recommended Practices
The Cybersecurity and Infrastructure Security Agency (CISA) recommends the following best practices to minimize exploitation risks:
- Minimize Network Exposure: Ensure control system devices are not accessible from the internet.
- Defensive Measures: Implement defense-in-depth strategies to protect ICS assets.
- Monitor for Malicious Activity: Follow established internal procedures to report and track suspicious activity.
- Risk Assessment: Perform thorough impact analysis and risk assessment before deploying defensive measures.
For more details, refer to CISA’s [ICS webpage](https://www.cisa.gov/ics) and the technical information paper [ICS-TIP-12-146-01B](https://www.cisa.gov/sites/default/files/FactSheets/NCCIC%20ICS_FactSheet_Defense_in_Depth_Strategies_S508C.pdf).
---
Conclusion
The CVE-2025-40942 vulnerability in Siemens TeleControl Server Basic highlights the ongoing risks faced by critical infrastructure sectors. Organizations must prioritize patching and adhere to industrial security best practices to mitigate potential threats. Siemens’ prompt response in releasing a patch underscores the importance of proactive cybersecurity measures in safeguarding essential services.
For further assistance, contact Siemens ProductCERT via their [advisory portal](https://www.siemens.com/cert/advisories).
---
References
[^1]: Siemens ProductCERT. "[SSA-192617: Local Privilege Escalation in TeleControl Server Basic](https://www.siemens.com/cert/advisories)". Retrieved 2025-01-24.
[^2]: CISA. "[ICS Advisory ICSA-26-015-03](https://www.cisa.gov/news-events/ics-advisories/icsa-26-015-03)". Retrieved 2025-01-24.
[^3]: MITRE. "[CWE-250: Execution with Unnecessary Privileges](https://cwe.mitre.org/data/definitions/250.html)". Retrieved 2025-01-24.