CVE-2022-4856 in Modbus Slave
Summary
by MITRE • 12/30/2022
A vulnerability has been found in Modbus Tools Modbus Slave up to 7.5.1 and classified as critical. Affected by this vulnerability is an unknown functionality of the file mbslave.exe of the component mbs File Handler. The manipulation leads to buffer overflow. The attack can be launched remotely. The exploit has been disclosed to the public and may be used. The identifier VDB-217021 was assigned to this vulnerability.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 01/26/2023
The vulnerability identified as CVE-2022-4856 represents a critical buffer overflow flaw in Modbus Tools Modbus Slave version 7.5.1 and earlier, specifically affecting the mbslave.exe executable within the mbs File Handler component. This vulnerability exposes a fundamental memory management issue that can be exploited through remote attack vectors, making it particularly dangerous in industrial control systems and networked environments where Modbus protocols are extensively deployed. The flaw resides in how the application processes file handling operations, creating opportunities for malicious actors to execute arbitrary code or cause system instability through carefully crafted input data.
The technical implementation of this buffer overflow vulnerability stems from inadequate bounds checking within the mbs File Handler component of the Modbus Slave application. When processing certain mbs files, the application fails to properly validate the size of incoming data before copying it into fixed-size memory buffers. This classic programming error allows attackers to overwrite adjacent memory locations, potentially leading to stack corruption, heap corruption, or execution flow redirection. The vulnerability specifically impacts the mbslave.exe process which serves as the core executable for handling Modbus slave operations, making it a critical point of failure in industrial automation environments.
The operational impact of this vulnerability extends beyond simple system crashes or hangs, as it provides attackers with potential paths to achieve persistent access within industrial control systems. Remote exploitation capabilities mean that adversaries can target systems without physical access, making this particularly concerning for critical infrastructure sectors that rely heavily on Modbus protocols for communication between devices. The disclosure of exploit code (VDB-217021) significantly increases the risk level, as it removes the barrier to entry for potential attackers who may not require advanced technical skills to leverage this vulnerability. Organizations using Modbus Slave software in production environments face immediate risk of unauthorized access, data manipulation, or system compromise.
Security professionals should immediately implement mitigation strategies including updating to the latest version of Modbus Tools Modbus Slave where the vulnerability has been patched, applying network segmentation to isolate affected systems, and implementing robust monitoring for anomalous file processing activities. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and may map to ATT&CK technique T1059.007 for command and scripting interpreter usage. Organizations should also consider implementing network-based intrusion detection systems to monitor for suspicious Modbus traffic patterns and file upload activities that could indicate exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of the vulnerable software in operational environments.