CVE-2025-40942 Overview
CVE-2025-40942 is a local privilege escalation vulnerability affecting Siemens TeleControl Server Basic in all versions prior to V3.1.2.4. The flaw allows an authenticated local attacker to execute arbitrary code with elevated privileges on the host running the application. Siemens TeleControl Server Basic is deployed in industrial and utility environments to manage remote terminal units and SCADA telecontrol communications. The weakness is categorized under CWE-250 (Execution with Unnecessary Privileges), indicating the application performs operations with more privilege than required. Siemens published advisory SSA-192617 with remediation guidance.
Critical Impact
A local, low-privileged attacker can escalate to elevated privileges and execute arbitrary code, compromising the confidentiality, integrity, and availability of the telecontrol server and connected industrial systems.
Affected Products
- Siemens TeleControl Server Basic — all versions prior to V3.1.2.4
- Deployments integrating TeleControl Server Basic with SIMATIC and SINAUT ST7 remote sites
- Industrial control environments using TeleControl Server Basic for RTU communications
Discovery Timeline
- 2026-01-13 - CVE-2025-40942 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-40942
Vulnerability Analysis
CVE-2025-40942 is a local privilege escalation flaw in Siemens TeleControl Server Basic. The application executes with privileges beyond what its runtime tasks require, mapping to [CWE-250]. An attacker with local access and low-level privileges on the host can leverage these excessive privileges to run arbitrary code in a higher-privileged security context. Successful exploitation impacts the confidentiality, integrity, and availability of both the vulnerable service and adjacent systems it can reach. In industrial deployments, this outcome extends to telecontrol communications and downstream RTU field devices.
Root Cause
The root cause is improper privilege management within TeleControl Server Basic. Components of the application run with privileges higher than necessary, which violates the principle of least privilege. When an authenticated local user interacts with those components, the elevated context becomes available to attacker-controlled code paths. Siemens has not published exploit-level detail, but the SSA-192617 advisory confirms the classification and the availability of a fixed release.
Attack Vector
The attack vector is local. An attacker must first obtain low-privileged access to the Windows host running TeleControl Server Basic, for example through stolen credentials, a phishing foothold, or an insider position. Exploitation also requires user interaction and an attack prerequisite condition, per the CVSS 4.0 vector. Once these preconditions are met, the attacker abuses the over-privileged application to execute code with elevated rights and pivot deeper into the operational technology environment.
No public proof-of-concept code is available for CVE-2025-40942. Refer to the Siemens Security Advisory SSA-192617 for authoritative technical details.
Detection Methods for CVE-2025-40942
Indicators of Compromise
- Unexpected child processes spawned by TeleControl Server Basic service binaries running under a privileged account.
- New or modified files, scheduled tasks, or services created in directories writable by the TeleControl Server Basic process.
- Local logons or interactive sessions on the telecontrol server host that precede anomalous privileged process activity.
Detection Strategies
- Baseline the normal process tree of TeleControl Server Basic and alert on deviations, especially command interpreters or scripting engines launched from the service context.
- Monitor Windows Security event IDs 4672 (special privileges assigned) and 4688 (process creation) correlated to the TeleControl Server Basic service account.
- Deploy behavioral endpoint detection on hosts running the application to identify privilege escalation patterns and unauthorized code execution.
Monitoring Recommendations
- Forward endpoint, application, and Windows security logs from telecontrol servers to a centralized analytics platform for correlation.
- Track file integrity on the TeleControl Server Basic installation directory and configuration files for unauthorized modifications.
- Alert on new local account creation, group membership changes, and privilege assignments on telecontrol hosts.
How to Mitigate CVE-2025-40942
Immediate Actions Required
- Upgrade Siemens TeleControl Server Basic to V3.1.2.4 or later on all affected hosts.
- Restrict interactive and remote local access to the telecontrol server to a minimal set of administrators.
- Audit local accounts and remove unnecessary logon rights on hosts running TeleControl Server Basic.
Patch Information
Siemens has released TeleControl Server Basic V3.1.2.4, which remediates CVE-2025-40942. Apply the update following the guidance in Siemens Security Advisory SSA-192617. Validate the fix in a staging environment before rolling out to production telecontrol systems to preserve availability of RTU communications.
Workarounds
- Where patching is not immediately possible, isolate the telecontrol server on a dedicated management network segment following Siemens operational guidelines for industrial security.
- Enforce application allowlisting on the host to block execution of unauthorized binaries from user-writable locations.
- Require multi-factor authentication for any remote administrative access to the server hosting TeleControl Server Basic.
# Verify the installed TeleControl Server Basic version on Windows
wmic product where "Name like 'TeleControl Server Basic%%'" get Name,Version
# Confirm the version is V3.1.2.4 or later; otherwise apply the Siemens update per SSA-192617
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
