CVE-2018-7762 in Modicon M340
Summary
by MITRE
A vulnerability exists in the web services to process SOAP requests in Schneider Electric's Modicon M340, Modicon Premium, Modicon Quantum PLC, BMXNOR0200 which could allow result in a buffer overflow.
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Analysis
by VulDB Data Team • 01/27/2020
The vulnerability identified as CVE-2018-7762 represents a critical buffer overflow flaw within the web services component of Schneider Electric's industrial control systems. This issue affects multiple PLC models including the Modicon M340, Modicon Premium, Modicon Quantum, and BMXNOR0200 devices, which are widely deployed in industrial environments for critical infrastructure control and automation. The vulnerability specifically manifests in the SOAP request processing functionality of these web services, creating a potential pathway for malicious actors to exploit the system through crafted network requests. The buffer overflow condition occurs when the system fails to properly validate input lengths during SOAP message processing, allowing an attacker to overflow memory buffers and potentially execute arbitrary code on the affected devices.
From a technical perspective, this vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The flaw exists in the web services implementation that handles SOAP protocol communications, making it particularly dangerous as industrial control systems often expose these services over networks for remote configuration and monitoring. The buffer overflow can be triggered through specially crafted SOAP requests sent to the vulnerable web service endpoints, potentially leading to complete system compromise. The attack vector is network-based, requiring no physical access to the devices and leveraging standard web service communication protocols that are commonly exposed in industrial environments.
The operational impact of this vulnerability extends beyond simple system compromise, as it directly threatens the integrity and availability of critical industrial processes. Industrial control systems running affected Schneider Electric PLCs could experience unauthorized access, data manipulation, or complete system disruption, potentially affecting production processes, safety systems, and operational continuity. The vulnerability's exploitation could lead to denial of service conditions where the affected devices become unresponsive, or more severe scenarios where attackers gain persistent access to control systems and can manipulate process variables or system configurations. Given the industrial context, this vulnerability poses significant risks to operational technology environments and could potentially impact safety-critical systems where control system integrity is paramount.
Mitigation strategies for CVE-2018-7762 should focus on immediate patching of affected systems, network segmentation to isolate industrial control systems from general network access, and implementation of network monitoring to detect unusual SOAP request patterns. Organizations should also consider disabling unnecessary web services functionality where possible and implementing proper input validation controls at network boundaries. The vulnerability aligns with ATT&CK technique T1210, which describes exploitation of remote services for privilege escalation, and T1071, which covers application layer protocol usage for command and control communications. Regular security assessments of industrial control system environments should be conducted to identify similar vulnerabilities, and organizations should maintain updated vulnerability management processes specifically tailored for operational technology environments to prevent similar issues from arising in the future.