CVE-2018-7845 in Modicon M580
Summary
by MITRE
A CWE-125: Out-of-bounds Read vulnerability exists in all versions of the Modicon M580, Modicon M340, Modicon Quantum, and Modicon Premium which could cause the disclosure of unexpected data from the controller when reading specific memory blocks in the controller over Modbus.
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Analysis
by VulDB Data Team • 09/23/2023
The vulnerability identified as CVE-2018-7845 represents a critical out-of-bounds read flaw classified under CWE-125 within several legacy industrial automation controllers including the Modicon M580, M340, Quantum, and Premium series. This issue manifests when these controllers process Modbus requests to read specific memory blocks, creating a scenario where the system accesses memory locations beyond the intended boundaries. The flaw stems from inadequate input validation and boundary checking mechanisms within the Modbus protocol implementation of these programmable logic controllers. Industrial control systems deployed in critical infrastructure environments are particularly susceptible to such vulnerabilities due to their extended operational lifecycles and the difficulty of implementing timely security updates.
The technical execution of this vulnerability occurs through malformed Modbus read requests that target specific memory addresses within the controller's address space. When processing these requests, the controller fails to properly validate the requested memory boundaries, allowing an attacker to read data from adjacent memory locations that should remain inaccessible. This behavior results in unintended data disclosure, potentially exposing sensitive operational information, configuration parameters, or even portions of the controller's internal state. The out-of-bounds memory access can reveal information such as system configuration details, communication parameters, or other confidential data that should not be accessible through normal operational procedures. This vulnerability directly impacts the confidentiality and integrity of industrial control systems, as it enables unauthorized information extraction without proper authentication or authorization.
The operational impact of CVE-2018-7845 extends beyond simple data disclosure, as it represents a fundamental security weakness that could enable more sophisticated attacks. Attackers could leverage this vulnerability to gather intelligence about the controller's configuration, memory layout, and potentially identify other system weaknesses. The vulnerability affects industrial environments where these controllers operate, including manufacturing plants, power generation facilities, and other critical infrastructure sectors. The risk is particularly elevated in environments where physical security controls are insufficient, as remote exploitation could occur through network-connected Modbus interfaces. This vulnerability aligns with ATT&CK technique T1046 for network service scanning and T1005 for data from local system, representing a pathway for reconnaissance and information gathering activities. Organizations using these controllers face potential operational disruptions if attackers exploit this vulnerability to understand system behavior and develop more targeted attacks.
Mitigation strategies for this vulnerability require immediate attention from industrial security teams, as the affected controllers represent legacy systems that may not receive regular security updates. The primary recommendation involves implementing network segmentation and access controls to limit unauthorized access to Modbus interfaces, particularly by restricting network access to only trusted systems. Organizations should deploy Modbus protocol filtering and monitoring solutions to detect anomalous read requests that might indicate exploitation attempts. Additionally, implementing network intrusion detection systems specifically configured to identify Modbus protocol anomalies can provide early warning of potential attacks. The affected manufacturers should be consulted regarding firmware updates or patches, though deployment of updates in industrial environments requires careful planning to avoid operational disruptions. Security teams should also consider implementing memory access monitoring and logging mechanisms to detect unauthorized memory access patterns. Organizations should conduct comprehensive vulnerability assessments of their industrial control systems to identify other potential out-of-bounds read vulnerabilities and ensure proper boundary checking mechanisms are in place across all industrial communication protocols. The vulnerability demonstrates the importance of applying security principles from the defense-in-depth strategy, ensuring that multiple layers of protection exist to prevent unauthorized access and information disclosure in critical infrastructure environments.