CVE-2020-27281 in CNCSoft ScreenEditor
Summary
by MITRE • 01/12/2021
A stack-based buffer overflow may exist in Delta Electronics CNCSoft ScreenEditor versions 1.01.26 and prior when processing specially crafted project files, which may allow an attacker to execute arbitrary code.
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Analysis
by VulDB Data Team • 02/11/2021
The vulnerability identified as CVE-2020-27281 represents a critical stack-based buffer overflow flaw within Delta Electronics CNCSoft ScreenEditor software version 1.01.26 and earlier iterations. This vulnerability specifically manifests during the processing of maliciously crafted project files, creating a potential attack vector that could enable remote code execution on affected systems. The flaw resides in the software's insufficient input validation mechanisms when handling project file data structures, particularly within memory allocation and data processing routines. The buffer overflow occurs when the application attempts to write data beyond the allocated stack buffer boundaries, potentially corrupting adjacent memory regions and allowing attackers to manipulate program execution flow. Such vulnerabilities are particularly dangerous in industrial control environments where CNC software systems manage critical manufacturing processes and may be accessible through network connections or removable media.
The technical implementation of this vulnerability stems from improper bounds checking within the project file parsing functionality of ScreenEditor. When processing specially crafted project files, the software fails to validate the size or structure of incoming data before attempting to copy it into fixed-size stack buffers. This classic buffer overflow condition allows an attacker to overwrite return addresses, function pointers, or other critical stack variables with malicious payload data. The vulnerability aligns with CWE-121 Stack-based Buffer Overflow, which specifically addresses buffer overflows occurring in stack memory regions. Attackers could exploit this by creating malicious project files containing oversized data structures or crafted payloads designed to overwrite the instruction pointer and redirect program execution to malicious code. The exploitation typically requires the victim to open the specially crafted project file, making social engineering or supply chain compromise potential attack vectors.
The operational impact of CVE-2020-27281 extends significantly within industrial environments where Delta Electronics CNCSoft ScreenEditor is deployed. Manufacturing facilities relying on these systems for production control may face unauthorized access to critical manufacturing processes, potentially leading to production disruption, data compromise, or even physical system damage. The vulnerability could enable attackers to execute arbitrary code with the privileges of the affected user, potentially escalating to system-level access depending on the execution context. Industrial control systems using this software may be particularly vulnerable due to limited security monitoring and the often isolated nature of these environments. The attack surface includes not only direct software exploitation but also potential lateral movement within networks where these systems are connected, as CNC software often interfaces with enterprise networks for data exchange or configuration management. Organizations using legacy versions of this software face heightened risk due to the lack of security updates or patches for older releases.
Mitigation strategies for CVE-2020-27281 should prioritize immediate software updates to the latest available versions of Delta Electronics CNCSoft ScreenEditor, which contain fixed implementations of input validation and buffer management routines. Organizations should implement strict file validation procedures for project files, including content scanning and access restriction policies to prevent execution of untrusted files. Network segmentation and access controls should be enforced to limit exposure of affected systems to untrusted networks or users. System administrators should disable unnecessary features and services related to project file handling, particularly those that automatically process files from external sources. Security monitoring should be enhanced to detect unusual file processing patterns or attempts to access vulnerable software components. The ATT&CK framework categorizes this vulnerability under T1203 Exploitation for Client Execution, highlighting the importance of endpoint protection and application whitelisting measures. Regular vulnerability assessments and penetration testing should be conducted to identify similar flaws in industrial control system software, particularly legacy applications that may not receive regular security updates. Additionally, implementing robust backup and recovery procedures ensures business continuity in case of successful exploitation, while maintaining detailed audit logs of project file access and modifications provides valuable forensic data for incident response activities.