CVE-2012-0929 in Modicon Quantum PLC
Summary
by MITRE
Multiple buffer overflows in Schneider Electric Modicon Quantum PLC allow remote attackers to cause a denial of service via malformed requests to the (1) FTP server or (2) HTTP server.
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Analysis
by VulDB Data Team • 11/29/2021
The vulnerability identified as CVE-2012-0929 represents a critical security flaw affecting Schneider Electric Modicon Quantum programmable logic controllers that operates at the network protocol level. These devices are widely deployed in industrial control systems and supervisory control and data acquisition environments where reliability and security are paramount. The vulnerability manifests as multiple buffer overflow conditions that can be exploited remotely through malformed requests directed at either the File Transfer Protocol or Hypertext Transfer Protocol servers running on the affected PLCs. This vulnerability directly impacts the availability and integrity of industrial control systems where these devices operate, creating potential risks for critical infrastructure operations.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the network service implementations of the Modicon Quantum PLC firmware. When the FTP or HTTP servers receive malformed requests containing oversized data payloads that exceed predetermined buffer sizes, the systems fail to properly handle these conditions, leading to memory corruption and subsequent system instability. The buffer overflow conditions occur during the processing of network packets where the PLCs do not perform proper bounds checking on received data, allowing attackers to overwrite adjacent memory locations with controlled data. This type of vulnerability is classified under CWE-121 as "Stack-based Buffer Overflow" and CWE-122 as "Heap-based Buffer Overflow" depending on the specific execution context, representing fundamental flaws in memory management practices within industrial control system firmware.
The operational impact of CVE-2012-0929 extends beyond simple denial of service conditions to potentially compromise the entire industrial control environment. Remote attackers can exploit these vulnerabilities to cause complete system outages, forcing operators to manually restart affected PLCs and potentially disrupting production processes. In critical infrastructure environments such as power generation, water treatment facilities, or manufacturing plants, such disruptions can lead to significant financial losses and safety risks. The vulnerability's remote exploitability means that attackers do not require physical access to the devices, making it particularly dangerous for industrial networks that may be connected to corporate networks or the internet. This characteristic aligns with ATT&CK technique T1190 for "Exploit Public-Facing Application" and T1499 for "Endpoint Denial of Service" in the MITRE ATT&CK framework for enterprise security.
Mitigation strategies for this vulnerability require immediate firmware updates from Schneider Electric, as the company has released patches specifically addressing these buffer overflow conditions. Organizations should implement network segmentation to isolate affected PLCs from general network access, deploy intrusion detection systems to monitor for suspicious traffic patterns, and establish strict access controls for industrial network services. Network administrators should also consider disabling unnecessary services such as FTP and HTTP servers when they are not actively required, reducing the attack surface available to potential attackers. The vulnerability demonstrates the importance of proper input validation and memory management practices in industrial control systems, highlighting the need for robust software security practices in critical infrastructure environments. Organizations should also implement regular vulnerability assessments and penetration testing specifically targeting industrial control systems to identify similar weaknesses before they can be exploited by malicious actors.