CVE-2020-5653 in MELSEC iQ-R
Summary
by MITRE • 11/03/2020
Buffer overflow vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R series (RJ71EIP91 EtherNet/IP Network Interface Module First 2 digits of serial number are '02' or before, RJ71PN92 PROFINET IO Controller Module First 2 digits of serial number are '01' or before, RD81DL96 High Speed Data Logger Module First 2 digits of serial number are '08' or before, RD81MES96N MES Interface Module First 2 digits of serial number are '04' or before, and RD81OPC96 OPC UA Server Module First 2 digits of serial number are '04' or before) allows a remote unauthenticated attacker to stop the network functions of the products or execute a malicious program via a specially crafted packet.
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Analysis
by VulDB Data Team • 12/01/2020
This buffer overflow vulnerability exists within the TCP/IP implementation of several Mitsubishi Electric industrial automation products within the MELSEC iQ-R series. The affected hardware includes specific models of EtherNet/IP Network Interface Module, PROFINET IO Controller Module, High Speed Data Logger Module, MES Interface Module, and OPC UA Server Module, each with distinct serial number prefixes that indicate vulnerability. The flaw resides in how these devices process incoming network packets, specifically in their handling of buffer allocations within the TCP/IP stack functionality that is embedded in their firmware. The vulnerability is classified as a classic buffer overflow that occurs when the system attempts to write more data into a fixed-length buffer than it can accommodate, leading to memory corruption and potential code execution.
The technical exploitation of this vulnerability requires an attacker to send a specially crafted packet to the affected device over the network without authentication. This remote attack vector allows for two primary outcomes: denial of service through network function disruption or arbitrary code execution on the affected device. The buffer overflow occurs during packet processing when the device fails to properly validate input lengths before copying data into internal buffers. This type of vulnerability maps directly to CWE-121, which describes stack-based buffer overflow conditions, and also aligns with CWE-122, heap-based buffer overflow scenarios, depending on the specific memory allocation pattern used by the vulnerable code. The attack can be classified under MITRE ATT&CK technique T1059.007 for command and script interpreter, as successful exploitation could enable attackers to execute malicious code on the industrial control system.
The operational impact of this vulnerability extends beyond simple network disruption, as these industrial devices form critical components within manufacturing and industrial control systems. When compromised, the affected modules can cause production line shutdowns, data integrity issues, or provide attackers with persistent access points within industrial networks. The vulnerability affects devices with serial number prefixes '02' or earlier for RJ71EIP91 modules, '01' or earlier for RJ71PN92 modules, '08' or earlier for RD81DL96 modules, and '04' or earlier for both RD81MES96N and RD81OPC96 modules. These devices typically operate in critical industrial environments where network availability and system integrity are paramount, making the potential for remote code execution particularly concerning. The lack of authentication requirements for exploitation means that any attacker with network access can potentially compromise these devices, representing a significant risk to operational technology infrastructure.
Mitigation strategies for this vulnerability should include immediate firmware updates from Mitsubishi Electric to address the buffer overflow conditions in the TCP/IP implementation. Network segmentation and access control measures should be implemented to limit exposure of these devices to untrusted networks, while monitoring for anomalous network traffic patterns may help detect exploitation attempts. Organizations should also consider implementing network intrusion detection systems specifically configured to identify malformed packets targeting these known vulnerable modules. The vulnerability demonstrates the critical importance of firmware security in industrial control systems and highlights the need for regular security assessments of operational technology infrastructure. Additionally, implementing network access controls and restricting network access to only necessary personnel can significantly reduce the attack surface for such remote exploitation scenarios.