CVE-2012-3017 in SIMATIC S7-400 Cpu 414-3 Pn
Summary
by MITRE
Siemens SIMATIC S7-400 PN CPU devices with firmware 5.x allow remote attackers to cause a denial of service (defect-mode transition and service outage) via (1) malformed HTTP traffic or (2) malformed IP packets.
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Analysis
by VulDB Data Team • 12/07/2021
The Siemens SIMATIC S7-400 PN CPU devices represent critical components within industrial control systems and automation environments, serving as the backbone for numerous manufacturing and infrastructure operations. These devices operate within the industrial internet of things ecosystem and are particularly vulnerable due to their remote accessibility and the high-value targets they represent. The specific firmware version 5.x of these programmable logic controllers contains a fundamental flaw that enables remote attackers to disrupt operations through carefully crafted network traffic, creating a significant risk to operational technology infrastructure.
The technical vulnerability manifests through two distinct attack vectors that exploit the device's handling of malformed network protocols. The first vector involves malformed HTTP traffic that triggers an improper response from the device's web server component, while the second vector targets malformed IP packets that cause the device's network stack to malfunction. Both attack methods leverage protocol parsing weaknesses that result in the device entering a defect mode state, where normal operations cease and the system transitions into a service outage condition. This behavior stems from insufficient input validation and error handling mechanisms within the device's network processing layers, creating a path for remote exploitation without requiring authentication or physical access.
The operational impact of this vulnerability extends beyond simple service interruption, as these devices typically control critical industrial processes and manufacturing equipment. When a S7-400 PN CPU enters defect mode, it can cause cascading failures throughout connected systems, potentially leading to production halts, safety system disruptions, and significant financial losses. The remote nature of the attack means that threat actors can target these devices from anywhere on the network, making traditional perimeter security measures ineffective. Organizations relying on these devices face substantial risk to their operational continuity, particularly in environments where industrial control systems operate 24/7 without scheduled maintenance windows.
Security professionals should recognize this vulnerability as aligning with CWE-129, which addresses improper validation of input boundaries, and CWE-347, concerning the lack of proper validation of cryptographic signatures. The attack vectors correspond to techniques described in the MITRE ATT&CK framework under the T1203 and T1499 sub-techniques, representing the exploitation of software vulnerabilities and the execution of denial of service attacks. Organizations should implement network segmentation to isolate these critical devices from general network traffic, deploy intrusion detection systems to monitor for malformed packets, and establish firmware update procedures to address the vulnerability. Additionally, regular security assessments and vulnerability scanning should be conducted to identify similar weaknesses in other industrial control system components, ensuring comprehensive protection against similar threats.