CVE-2021-46644 in MicroStation CONNECT
Summary
by MITRE • 02/18/2022
This vulnerability allows remote attackers to execute arbitrary code on affected installations of Bentley MicroStation CONNECT 10.16.0.80. 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 DGN files. Crafted data in a DGN file can trigger a write past the end of an allocated buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-15530.
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Analysis
by VulDB Data Team • 02/19/2022
This vulnerability represents a critical buffer overflow flaw in Bentley MicroStation CONNECT 10.16.0.80 that enables remote code execution through crafted DGN files. The vulnerability stems from inadequate input validation during the parsing of DGN file format structures, specifically when processing malformed buffer boundaries. The flaw manifests as a write past the end of an allocated buffer, which occurs when the software fails to properly validate the size and boundaries of data structures within the DGN file format. This type of vulnerability falls under CWE-121, which categorizes buffer overflow conditions where insufficient boundary checks allow memory corruption. The attack vector requires user interaction through either visiting a malicious webpage or opening a specially crafted DGN file, making it particularly dangerous in social engineering scenarios where users might inadvertently encounter such files.
The technical implementation of this vulnerability exploits the inherent trust placed in file format parsing within desktop applications. When MicroStation processes a DGN file containing maliciously crafted data, the buffer overflow occurs during the memory allocation and data copying operations. The attacker can manipulate the DGN file structure to force the application into writing beyond allocated memory boundaries, potentially overwriting adjacent memory locations including function pointers or return addresses. This memory corruption allows an attacker to redirect execution flow and inject arbitrary code within the application's process context. The vulnerability demonstrates a classic stack-based buffer overflow pattern where the attacker controls both the amount of data written and the target memory location, enabling privilege escalation to the current user's privileges.
The operational impact of this vulnerability extends beyond simple code execution, potentially allowing attackers to establish persistent access to affected systems through various attack techniques. According to ATT&CK framework, this vulnerability maps to T1059 for command and script interpreter execution, as well as T1068 for exploit for privilege escalation. The remote code execution capability means that attackers can deploy malware payloads, establish backdoors, or perform reconnaissance activities without requiring local system access. Organizations using Bentley MicroStation in engineering environments face significant risk, as the software is commonly used in design and construction workflows where users frequently exchange DGN files. The vulnerability's exploitation requires minimal technical expertise from attackers, making it attractive for widespread use in targeted attacks against engineering firms, government agencies, or critical infrastructure organizations that rely on this software.
Mitigation strategies should focus on immediate patching of the affected software version, combined with network-level defenses to prevent access to malicious DGN files. Organizations should implement strict file validation policies and consider sandboxing mechanisms when processing untrusted DGN files. The vulnerability's classification as a buffer overflow indicates that traditional input sanitization techniques may not be sufficient, requiring more robust memory safety measures. Security teams should monitor for exploitation attempts through network traffic analysis and endpoint detection systems that can identify suspicious file processing activities. Regular security updates and vulnerability assessments of engineering software suites are essential to prevent similar issues in other components of the software ecosystem. Additionally, user education about the dangers of opening untrusted files remains critical, as this vulnerability specifically requires user interaction for exploitation to occur.