CVE-2021-34944

Vulnerability

An out-of-bounds read vulnerability exists in Bentley View version 10.15.0.75 during the parsing of specially crafted JT files. The issue stems from the lack of proper validation of user-supplied data, which can result in a read past the end of an allocated buffer [1]. The flaw is part of a larger set of similar issues addressed in Bentley’s advisory BE-2021-0005 [1].

Exploitation

To exploit this vulnerability, an attacker must convince a user to open a malicious JT file (or visit a page that triggers the file open) using Bentley View. No authentication or special network position is required because the attack is delivered via user interaction. The out-of-bounds read occurs when the application’s JT file parser processes the malicious data without adequate bounds checking [2].

Impact

A successful exploit allows an attacker to read sensitive information from the process memory (information disclosure). The disclosure can be used as a stepping stone to achieve arbitrary code execution in the context of the current process when combined with other vulnerabilities [2]. The CVSS v3.1 score for this specific CVE is 3.3 (low severity) due to the limited direct impact, but the ZDI advisory notes that it can be leveraged with other bugs for higher impact [2].

Mitigation

Bentley has addressed this issue as part of BE-2021-0005. Users should update Bentley View to a version newer than 10.15.0.75 that includes the fixes. The advisory does not specify a fixed version number, but the update was published on 2021-12-07 [1]. There is no known workaround for unpatched versions; users should treat untrusted JT files with caution until the update is applied [1][2].