CVE-2025-40943 in SIMATIC Drive Controller CPU 1504D TF
Summary
by MITRE • 03/10/2026
Affected devices do not properly sanitize contents of trace files.
This could allow an attacker to inject code through social engineering an authorized user, who has the function right "Read diagnostics", to import a specially crafted trace file.
The malicious trace file is insufficiently sanitized and malicious code could be executed in the clients browser session and trigger PLC operations via the webserver that the legitimate user is authorized to perform.
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Analysis
by VulDB Data Team • 03/19/2026
This vulnerability exists in industrial control systems where trace file processing lacks proper input sanitization mechanisms. The flaw allows attackers to craft malicious trace files that bypass security controls when imported by authorized users possessing the "Read diagnostics" privilege. The vulnerability stems from inadequate validation and sanitization of trace file contents before processing, creating a path for code injection attacks that leverage social engineering tactics to compromise legitimate users.
The technical implementation of this vulnerability involves the improper handling of trace file data within the web server interface. When an authorized user with diagnostic reading permissions imports a crafted trace file, the system fails to properly validate or sanitize the file contents. This insufficient sanitization creates a code execution vector that operates within the user's browser session, allowing malicious code to run in the context of the authenticated user. The vulnerability specifically targets the web-based interface that provides access to programmable logic controller operations, enabling attackers to execute PLC commands through the legitimate user's authorized session.
The operational impact of this vulnerability is significant for industrial environments where security is paramount. An attacker can leverage this flaw to gain unauthorized access to critical control system functions without requiring additional authentication credentials. The attack requires social engineering to convince an authorized user to import the malicious trace file, but once executed, the attacker can perform operations that the legitimate user is authorized to perform, including triggering PLC operations. This creates a sophisticated attack vector that combines traditional code injection techniques with social engineering to bypass security controls.
Security controls should focus on implementing comprehensive input validation and sanitization for all trace file processing operations. The system must validate file contents against strict whitelists and sanitize all data before processing to prevent code injection attacks. Organizations should implement multi-factor authentication and privilege separation to limit the impact of compromised accounts. The vulnerability aligns with CWE-74 and CWE-79 categories related to injection flaws and cross-site scripting attacks. From an att&ck framework perspective, this represents a technique involving social engineering and privilege escalation through code injection, specifically targeting the web application layer and operational technology infrastructure.