CVE-2021-34945 in View
Summary
by MITRE • 01/14/2022
This vulnerability allows remote attackers to execute arbitrary code on affected installations of Bentley View 10.15.0.75. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the parsing of JT files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-15054.
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Analysis
by VulDB Data Team • 01/17/2022
This vulnerability represents a critical buffer overflow flaw in Bentley View 10.15.0.75 that enables remote code execution through malicious JT file manipulation. The vulnerability stems from insufficient input validation during the parsing of JT (JT Solid Model) files, which are commonly used in engineering and architectural software for 3D model visualization. The flaw occurs when the application processes user-supplied data without properly validating the length of the input before copying it into a heap-based buffer, creating a classic buffer overflow condition. This type of vulnerability falls under CWE-121, heap-based buffer overflow, and specifically aligns with ATT&CK technique T1203, Exploitation for Client Execution, as it requires user interaction to deliver the malicious payload through web browsing or file opening activities.
The technical implementation of this vulnerability allows attackers to craft specially crafted JT files that, when processed by the vulnerable Bentley View application, trigger the buffer overflow condition. When a user visits a malicious webpage hosting the exploit or opens the crafted file, the application's JT parser fails to validate input lengths properly, leading to memory corruption that can be leveraged to execute arbitrary code within the application's security context. The heap-based nature of the buffer means that the overflow can overwrite adjacent memory locations, potentially allowing attackers to redirect execution flow, inject malicious code, or manipulate program state. This vulnerability is particularly concerning because it requires no privileged access or special system conditions to exploit, making it accessible to attackers with minimal prerequisites.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with full control over the affected system where Bentley View is installed. Since the exploitation occurs within the context of the current process, attackers can potentially access sensitive data, modify files, establish persistence mechanisms, or use the compromised system as a launch point for further attacks within the network. The requirement for user interaction makes this a client-side exploit that could be delivered through phishing campaigns, malicious websites, or social engineering tactics, significantly increasing the attack surface. Organizations using Bentley View for engineering and architectural work are particularly at risk since these applications often handle sensitive project data and may be installed on workstations with elevated privileges.
Mitigation strategies should focus on immediate patch application from Bentley as the primary defense mechanism, while also implementing network-based controls such as web application firewalls and content filtering to prevent access to malicious JT files. Organizations should also consider restricting user access to potentially harmful file types through group policies and endpoint protection solutions. Additionally, implementing security awareness training to prevent users from visiting malicious websites or opening suspicious files can significantly reduce exploitation risk. The vulnerability highlights the importance of proper input validation and bounds checking in software development practices, aligning with security standards that emphasize secure coding methodologies and defensive programming techniques to prevent similar issues in future releases.