CVE-2022-1068 in Slave
Summary
by MITRE • 04/02/2022
Modbus Tools Modbus Slave (versions 7.4.2 and prior) is vulnerable to a stack-based buffer overflow in the registration field. This may cause the program to crash when a long character string is used.
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Analysis
by VulDB Data Team • 04/05/2022
The vulnerability identified as CVE-2022-1068 affects Modbus Tools Modbus Slave software version 7.4.2 and earlier, representing a critical stack-based buffer overflow condition within the application's registration field processing mechanism. This flaw constitutes a fundamental memory safety issue that arises when the software fails to properly validate input length before copying data into a fixed-size stack buffer. The vulnerability specifically manifests when an attacker provides an excessively long character string to the registration field, which triggers the buffer overflow condition.
The technical implementation of this vulnerability stems from improper input validation within the Modbus Slave application's registration handling code. When a user inputs a character string that exceeds the allocated buffer size in memory, the excess data overflows into adjacent stack memory locations, potentially corrupting critical program data or execution control structures. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, which is classified as a serious memory safety issue that can lead to arbitrary code execution or application crashes. The stack-based nature of the overflow indicates that the vulnerable code likely uses local variables or function parameters that are stored on the program's stack memory segment, making it susceptible to overwriting adjacent memory locations.
The operational impact of this vulnerability extends beyond simple application instability, as it creates potential attack vectors for malicious actors seeking to disrupt industrial control systems that rely on Modbus communication protocols. Modbus Slave applications are commonly deployed in industrial environments where system reliability is paramount, making this vulnerability particularly concerning for operational technology infrastructure. When exploited, the buffer overflow can cause the application to terminate unexpectedly, potentially leading to service disruption in critical infrastructure monitoring systems. The crash condition may also provide opportunities for attackers to perform denial of service attacks against industrial processes or potentially escalate privileges if the application runs with elevated permissions. This vulnerability directly impacts the availability and integrity of industrial communication systems that depend on Modbus protocols for data exchange.
Mitigation strategies for CVE-2022-1068 should prioritize immediate software updates to versions that address the buffer overflow condition, as this represents the most effective defense against exploitation. Organizations should implement input validation measures that enforce strict length limits on registration field entries, preventing the acceptance of overly long character strings that could trigger the overflow condition. Network segmentation and access controls should be strengthened to limit exposure of vulnerable Modbus Slave instances to untrusted networks or users. Security monitoring should include detection of unusual registration attempts or malformed input patterns that might indicate exploitation attempts. Additionally, system administrators should conduct comprehensive vulnerability assessments to identify all instances of the affected software across their industrial control networks, ensuring that all potentially vulnerable systems receive appropriate updates. The remediation process should follow industry best practices for patch management in operational technology environments, considering the critical nature of industrial control systems and the potential consequences of system disruptions.