CVE-2017-9312 in L30ERMS
Summary
by MITRE
Improperly implemented option-field processing in the TCP/IP stack on Allen-Bradley L30ERMS safety devices v30 and earlier causes a denial of service. When a crafted TCP packet is received, the device reboots immediately.
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Analysis
by VulDB Data Team • 02/21/2020
The vulnerability described in CVE-2017-9312 represents a critical flaw in the network stack implementation of Allen-Bradley L30ERMS safety devices running firmware versions 30 and earlier. This issue stems from inadequate handling of TCP option fields within the device's network protocol stack, creating a condition where malformed network traffic can trigger unintended system behavior. The vulnerability specifically affects industrial safety equipment used in critical infrastructure environments, where reliability and continuous operation are paramount for operational safety.
The technical root cause of this vulnerability lies in the improper processing of TCP option fields during network packet handling. When a specially crafted TCP packet containing malformed or unexpected option data is transmitted to the affected device, the TCP/IP stack fails to properly validate or sanitize these option fields before processing. This implementation flaw creates a buffer overflow condition or memory corruption scenario that ultimately leads to system instability. The vulnerability is classified as a denial of service condition because the device immediately reboots upon receiving the malicious packet, effectively removing the device from operational service.
From an operational perspective, this vulnerability presents significant risk to industrial control systems and safety-critical environments where Allen-Bradley L30ERMS devices are deployed. The immediate reboot behavior eliminates any possibility of graceful degradation or fail-safe operations, potentially leading to complete system outages during critical operations. The attack vector is particularly concerning because it requires only the transmission of a single malformed TCP packet to trigger the vulnerability, making it accessible to attackers with minimal network access. This characteristic aligns with ATT&CK technique T1499.004 for network denial of service attacks and represents a direct threat to operational technology infrastructure.
The impact of this vulnerability extends beyond simple service interruption as it affects the fundamental safety mechanisms of industrial control systems. When safety devices like the L30ERMS reboot unexpectedly, it can cause cascading failures throughout the industrial process, potentially leading to unsafe operating conditions or production losses. The vulnerability's classification as a denial of service attack under CWE-400 indicates improper input validation, specifically in network protocol handling, which is a common weakness in embedded systems and industrial controllers. Organizations using these devices must consider the broader implications of such vulnerabilities, particularly in environments where network connectivity is essential for safety operations and where traditional cybersecurity measures may not adequately protect industrial assets.
Mitigation strategies for this vulnerability should include immediate firmware updates from Allen-Bradley to address the TCP option field processing flaw. Network segmentation and access control measures should be implemented to limit exposure to untrusted network traffic, while monitoring systems should be deployed to detect anomalous TCP packet patterns that might indicate exploitation attempts. The vulnerability highlights the importance of secure network design in industrial environments and the need for comprehensive vulnerability management programs that address both traditional IT and operational technology assets. Organizations should also consider implementing network intrusion detection systems specifically tuned to identify malformed TCP packets targeting industrial control system devices.