CVE-2015-6460 in CODESYS Gateway Server
Summary
by MITRE
Multiple heap-based buffer overflows in 3S-Smart CODESYS Gateway Server before 2.3.9.47 allow remote attackers to execute arbitrary code via opcode (1) 0x3ef or (2) 0x3f0.
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Analysis
by VulDB Data Team • 05/11/2018
The vulnerability identified as CVE-2015-6460 represents a critical heap-based buffer overflow in the 3S-Smart CODESYS Gateway Server software, specifically affecting versions prior to 2.3.9.47. This issue arises from improper input validation within the server's handling of specific opcodes, creating a pathway for remote code execution that could be exploited by malicious actors without requiring authentication. The affected opcodes 0x3ef and 0x3f0 are part of the communication protocol used by the CODESYS industrial automation platform, which is widely deployed in industrial control systems and supervisory control and data acquisition environments. The vulnerability stems from inadequate bounds checking in memory allocation routines, where attacker-controlled data is processed without sufficient validation, leading to memory corruption that can be leveraged for arbitrary code execution.
The technical flaw manifests as a heap-based buffer overflow that occurs when the server processes incoming network packets containing the specified opcodes. When these opcodes are received, the system attempts to allocate memory for processing the data but fails to properly validate the size of incoming data structures. This allows an attacker to overflow the allocated buffer and overwrite adjacent memory locations, potentially corrupting program execution flow or injecting malicious code into the running process. The heap-based nature of the vulnerability means that memory corruption occurs in the heap segment rather than the stack, making exploitation more complex but still highly dangerous as it can lead to complete system compromise. The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of insufficient boundary checking in memory management operations.
The operational impact of this vulnerability is particularly severe given the widespread deployment of CODESYS Gateway Server in industrial environments where security is paramount. Attackers exploiting this vulnerability could gain remote code execution privileges on affected systems, potentially leading to complete system compromise, data exfiltration, or disruption of industrial processes. The lack of authentication requirements for exploitation makes this vulnerability particularly dangerous in unsecured network environments where industrial control systems may be directly accessible from external networks. Organizations using this software in critical infrastructure applications face significant risk of operational disruption, regulatory compliance violations, and potential safety hazards in environments such as manufacturing plants, power generation facilities, or water treatment systems where industrial control systems are deployed. The vulnerability also increases the attack surface for advanced persistent threats targeting industrial control systems, as it provides a direct path for attackers to establish persistent access within these environments.
Mitigation strategies for CVE-2015-6460 should prioritize immediate software updates to version 2.3.9.47 or later, which contain patches addressing the buffer overflow conditions. Network segmentation and access control measures should be implemented to restrict access to affected systems, particularly ensuring that industrial control systems are isolated from general network access. Firewall rules should be configured to block unauthorized access to the specific ports used by the CODESYS Gateway Server, typically including TCP ports 2407 and 2408. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of vulnerable software within the network infrastructure. Additionally, organizations should implement network monitoring solutions capable of detecting anomalous traffic patterns that might indicate exploitation attempts. The vulnerability also highlights the importance of secure coding practices and input validation, aligning with ATT&CK technique T1059.007 for execution through command and script interpreter, as exploitation typically involves injecting malicious code into the running process through buffer overflow conditions. System hardening measures including disabling unnecessary services, implementing least privilege access controls, and maintaining up-to-date security patches across all industrial control system components remain essential defensive measures against similar vulnerabilities in operational technology environments.