CVE-2011-3486 in TwinCAT
Summary
by MITRE
Beckhoff TwinCAT 2.11.0.2004 and earlier allows remote attackers to cause a denial of service via a crafted request to UDP port 48899, which triggers an out-of-bounds read.
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Analysis
by VulDB Data Team • 02/16/2025
The vulnerability identified as CVE-2011-3486 affects Beckhoff TwinCAT versions 2.11.0.2004 and earlier, representing a critical security flaw that enables remote attackers to execute denial of service attacks against industrial control systems. This issue specifically targets UDP port 48899, which serves as the communication endpoint for TwinCAT's remote control functionality. The flaw stems from inadequate input validation within the software's network handling mechanisms, creating a scenario where malformed packets can trigger unexpected behavior in the system's memory management processes.
The technical root cause of this vulnerability lies in an out-of-bounds read condition that occurs when the TwinCAT software processes incoming UDP packets on port 48899. When a remote attacker crafts a specially designed request containing malformed data, the application fails to properly validate the packet structure before attempting to access memory locations beyond the allocated buffer boundaries. This programming error falls under the category of CWE-129, which specifically addresses insufficient input validation leading to out-of-bounds reads. The vulnerability demonstrates a classic buffer overrun scenario where the software does not adequately check array indices or buffer limits before performing memory operations.
From an operational perspective, this vulnerability presents significant risks to industrial environments that rely on Beckhoff TwinCAT for automation and control systems. The denial of service attack can render critical industrial processes unavailable, potentially causing production downtime, safety system failures, or operational disruptions that may extend beyond simple network connectivity issues. The remote nature of the exploit means that attackers do not require physical access to the network or system, making it particularly dangerous in environments where industrial control systems are connected to corporate networks or the internet. This vulnerability directly impacts the availability aspect of the CIA triad, compromising the system's ability to provide continuous service to legitimate users and operators.
The exploitation of this vulnerability aligns with several tactics described in the MITRE ATT&CK framework, particularly those related to denial of service and network service disruption. Attackers can leverage this flaw to systematically target industrial control systems without requiring advanced technical skills or specialized equipment, making it an attractive vector for both opportunistic and targeted attacks. Organizations using affected TwinCAT versions face the risk of cascading failures where a single compromised device can affect larger network segments, particularly in scenarios where multiple controllers communicate through the same network infrastructure. The vulnerability also demonstrates the importance of network segmentation and proper firewall configurations to limit exposure of industrial control systems to external threats.
Organizations should immediately implement mitigations including applying the vendor-provided patches and updates released to address this vulnerability, as well as implementing network-level controls to restrict access to UDP port 48899. Network segmentation strategies should be employed to isolate industrial control systems from general corporate networks, and proper firewall rules should be configured to limit access to only trusted sources. Additionally, monitoring systems should be deployed to detect anomalous network traffic patterns that may indicate exploitation attempts. The vulnerability highlights the critical need for regular security assessments of industrial control systems and emphasizes the importance of maintaining up-to-date firmware and software versions to protect against known security flaws that could compromise operational technology environments.