CVE-2021-32939 in FvDesigner
Summary
by MITRE • 08/11/2021
FATEK Automation FvDesigner, Versions 1.5.88 and prior is vulnerable to an out-of-bounds write while processing project files, allowing an attacker to craft a project file that may permit arbitrary code execution.
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Analysis
by VulDB Data Team • 08/16/2021
The vulnerability identified as CVE-2021-32939 affects FATEK Automation FvDesigner software versions 1.5.88 and earlier, presenting a critical security risk through an out-of-bounds write condition during project file processing. This flaw resides within the software's handling of user-supplied input data, specifically when parsing project files that contain malformed or maliciously crafted data structures. The vulnerability stems from insufficient bounds checking mechanisms within the application's file parsing routines, which fail to validate the size and structure of incoming data before attempting to write to memory locations. Such inadequate input validation creates a pathway for attackers to manipulate the application's memory management behavior, potentially leading to arbitrary code execution. The out-of-bounds write vulnerability represents a fundamental flaw in the software's defensive programming practices and aligns with CWE-787, which specifically addresses out-of-bounds write conditions in software applications. This type of vulnerability is particularly dangerous in industrial automation environments where FvDesigner is commonly deployed, as it could enable attackers to compromise critical control systems and potentially disrupt industrial operations.
The technical exploitation of this vulnerability requires an attacker to craft a specially designed project file that triggers the out-of-bounds write condition when processed by the vulnerable FvDesigner application. When the application attempts to write data beyond the allocated memory boundaries, the operation can overwrite adjacent memory locations, potentially corrupting critical program data or executing attacker-controlled code. The attack vector is typically through social engineering or supply chain compromise, where an attacker delivers a malicious project file to an unsuspecting user who then opens it within the vulnerable software environment. This scenario aligns with ATT&CK technique T1204.002, which involves user execution of malicious content through legitimate application interfaces. The vulnerability's impact extends beyond simple code execution, as successful exploitation could allow attackers to gain full control over the affected system, potentially enabling lateral movement within network environments or persistence mechanisms. The memory corruption resulting from the out-of-bounds write can manifest in various ways including application crashes, unexpected behavior, or complete system compromise depending on the specific memory locations overwritten and the attacker's objectives.
The operational impact of CVE-2021-32939 in industrial automation settings is particularly severe, as FvDesigner is commonly used in manufacturing and process control environments where system reliability and security are paramount. Organizations utilizing this software in critical infrastructure applications face significant risk of operational disruption, data compromise, or safety incidents if exploited. The vulnerability affects not only the immediate execution environment but also the broader industrial control system landscape, as compromised systems could potentially be used as entry points for attacking other connected systems within the operational technology network. The attack surface is expanded in environments where multiple users have access to project files or where automated file sharing mechanisms exist, increasing the probability of successful exploitation. Additionally, the vulnerability may persist across multiple systems if the same malicious project file is distributed, creating a widespread risk that could affect entire production facilities. The lack of proper input validation in the software's project file handling routines means that any user with access to create or modify project files could potentially trigger this vulnerability, making it particularly challenging to secure in multi-user environments.
Organizations should immediately implement mitigation strategies to protect against exploitation of CVE-2021-32939, beginning with the immediate upgrade to FvDesigner version 1.5.89 or later, which contains the necessary patches to address the out-of-bounds write vulnerability. System administrators should also implement strict file access controls and validate all project files before processing, particularly those received from external sources or untrusted users. Network segmentation and monitoring should be enhanced to detect unusual file processing activities that might indicate exploitation attempts. The implementation of application whitelisting policies can prevent unauthorized versions of FvDesigner from executing on critical systems, while regular security assessments should be conducted to identify and remediate similar vulnerabilities in other industrial automation software. Organizations should also consider implementing behavioral monitoring solutions that can detect anomalous memory access patterns or process execution behaviors indicative of exploitation attempts. Additionally, staff training programs should emphasize the importance of verifying file sources and avoiding the opening of untrusted project files, as human error remains a significant factor in successful exploitation of such vulnerabilities. The remediation process should include thorough testing of patched versions in controlled environments before deployment to production systems to ensure that the security updates do not introduce regressions or compatibility issues in existing automation workflows.