CVE-2014-2257 in SIMATIC S7-1500 Cpu
Summary
by MITRE
Siemens SIMATIC S7-1500 CPU PLC devices with firmware before 1.5.0 allow remote attackers to cause a denial of service (defect-mode transition) via crafted ISO-TSAP packets.
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Analysis
by VulDB Data Team • 05/08/2026
The vulnerability identified as CVE-2014-2257 affects Siemens SIMATIC S7-1500 CPU programmable logic controllers where firmware versions prior to 1.5.0 contain a critical flaw in the handling of ISO-TSAP protocol packets. This weakness enables remote attackers to manipulate the device into transitioning into a defect mode, effectively causing a denial of service condition that disrupts industrial automation processes. The issue stems from insufficient input validation and error handling within the communication stack of these industrial control devices.
The technical implementation of this vulnerability involves the manipulation of ISO-TSAP (ISO Transport Service Access Point) packets that form part of the standard communication protocol used by Siemens PLCs for industrial automation. When the S7-1500 CPU receives specifically crafted ISO-TSAP packets, the device fails to properly validate the packet structure and content, leading to an unexpected state transition. This flaw operates at the network protocol level and requires no authentication or authorization, making it particularly dangerous in industrial environments where such devices operate continuously and without direct user interaction. The defect-mode transition essentially places the PLC into a non-operational state where it cannot process normal control commands, effectively halting production processes that depend on these automation systems.
The operational impact of this vulnerability extends beyond simple service disruption as it can compromise entire industrial control systems that rely on continuous operation of S7-1500 devices. In manufacturing environments, this could lead to production line shutdowns, quality control failures, and potentially dangerous situations where automated safety systems become non-responsive. The remote nature of the attack means that adversaries can exploit this vulnerability from external networks without requiring physical access to the industrial infrastructure, making it particularly concerning for critical manufacturing and process control environments. This vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and represents a significant weakness in the industrial control system security posture that affects the availability and integrity of automated processes.
Organizations should implement immediate mitigation strategies including firmware updates to version 1.5.0 or later, network segmentation to isolate industrial control systems from general corporate networks, and deployment of network monitoring solutions to detect anomalous ISO-TSAP traffic patterns. The implementation of network access control lists and firewall rules that restrict communication to only trusted sources can help reduce exposure. Additionally, regular vulnerability assessments and security audits of industrial control systems should be conducted to identify similar weaknesses in other components of the automation infrastructure. This vulnerability demonstrates the critical need for robust security practices in industrial environments where traditional cybersecurity measures may be insufficient to address the unique challenges posed by operational technology systems, and aligns with ATT&CK technique T1499 for network denial of service attacks targeting industrial control systems.