CVE-2019-6553 in RSLinx Classic
Summary
by MITRE
A vulnerability was found in Rockwell Automation RSLinx Classic versions 4.10.00 and prior. An input validation issue in a .dll file of RSLinx Classic where the data in a Forward Open service request is passed to a fixed size buffer, allowing an attacker to exploit a stack-based buffer overflow condition.
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Analysis
by VulDB Data Team • 08/27/2023
The vulnerability identified as CVE-2019-6553 resides within Rockwell Automation RSLinx Classic software version 4.10.00 and earlier, representing a critical security flaw that impacts industrial control systems and operational technology environments. This issue manifests as a stack-based buffer overflow condition that occurs during the processing of Forward Open service requests within the software's communication framework. The vulnerability specifically affects the input validation mechanisms of a dynamic link library component that handles industrial communication protocols, creating a pathway for malicious actors to exploit the system through carefully crafted network traffic.
The technical flaw stems from inadequate input validation within the RSLinx Classic software where data received in Forward Open service requests is directly copied into a fixed-size buffer without proper bounds checking. This programming error creates a condition where an attacker can supply more data than the allocated buffer space, causing a stack overflow that can potentially overwrite adjacent memory locations. The vulnerability falls under CWE-121 Stack-based Buffer Overflow, a well-documented weakness that has been consistently exploited in industrial control systems and OT environments. The attack vector involves sending maliciously formatted Forward Open requests to the vulnerable RSLinx Classic service, which then processes this data without sufficient validation, leading to the buffer overflow condition.
The operational impact of this vulnerability extends beyond traditional cybersecurity concerns to affect industrial operations and safety systems that rely on Rockwell Automation products. An attacker who successfully exploits this vulnerability could potentially execute arbitrary code on the affected system, gain elevated privileges, or cause system instability that could disrupt critical manufacturing processes. The attack could lead to unauthorized access to industrial control networks, data manipulation, or even physical system compromise in environments where RSLinx Classic serves as a communication gateway between different industrial protocols. This vulnerability particularly affects environments using EtherNet/IP and other Rockwell Automation protocols where the software acts as a bridge between field devices and higher-level control systems. The potential for remote code execution makes this a high-risk vulnerability for industrial environments that may not have traditional IT security controls in place.
Mitigation strategies for CVE-2019-6553 should prioritize immediate software updates from Rockwell Automation to the latest available versions that contain the patched buffer validation logic. Organizations should implement network segmentation to isolate RSLinx Classic services from critical industrial control systems and limit access to only authorized personnel. Security monitoring should be enhanced to detect unusual Forward Open service request patterns that might indicate exploitation attempts. The implementation of network access controls and firewall rules to restrict communication to essential ports and protocols can significantly reduce the attack surface. Additionally, regular vulnerability assessments and penetration testing should be conducted to identify similar issues in other industrial control system components, as this vulnerability demonstrates the importance of proper input validation in OT environments. Organizations should also consider implementing intrusion detection systems specifically tuned to detect exploitation attempts targeting industrial protocols and maintain detailed network monitoring logs for forensic analysis should an incident occur. The ATT&CK framework categorizes this type of vulnerability under T1059 Command and Scripting Interpreter and T1203 Exploitation for Client Execution, highlighting the need for both preventive and detective security controls in industrial environments.