CVE-2021-31496 in Brava Desktop
Summary
by MITRE • 06/15/2021
This vulnerability allows remote attackers to execute arbitrary code on affected installations of OpenText Brava! Desktop 16.6.3.84. 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 DXF files. The issue results from the lack of proper validation of user-supplied data, which can result in 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-13308.
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Analysis
by VulDB Data Team • 06/18/2021
The vulnerability identified as CVE-2021-31496 represents a critical buffer overflow flaw in OpenText Brava! Desktop version 16.6.3.84 that enables remote code execution through malicious DXF file manipulation. This security weakness resides within the application's file parsing engine specifically when processing AutoCAD Drawing Exchange Format files, making it particularly dangerous given the widespread use of DXF files in engineering and design environments. The vulnerability operates at the intersection of software security and file format processing, where proper input validation fails to prevent malicious data from overwriting adjacent memory regions.
The technical implementation of this flaw stems from inadequate bounds checking during DXF file parsing operations, creating a classic buffer overflow condition that allows attackers to write past the end of allocated memory buffers. This memory corruption vulnerability directly aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a sophisticated exploitation vector that requires careful crafting of malicious DXF content. The flaw manifests when the application attempts to parse malformed DXF structures that exceed expected buffer boundaries, enabling attackers to manipulate memory layout and potentially overwrite critical program structures.
From an operational perspective, this vulnerability creates a significant attack surface for threat actors targeting organizations that utilize OpenText Brava! Desktop for document review and collaboration. The requirement for user interaction through visiting malicious web pages or opening compromised files aligns with ATT&CK technique T1203, which covers exploitation for persistence through user interaction. This user-mediated execution requirement actually makes the vulnerability more practical to exploit in real-world scenarios, as it can be delivered through social engineering campaigns targeting end users or through compromised web applications that serve malicious DXF files. The attack vector demonstrates how seemingly benign file formats can become weaponized delivery mechanisms for remote code execution.
The impact of successful exploitation extends beyond simple code execution, as the vulnerability allows attackers to operate within the security context of the currently running process, potentially escalating privileges or accessing sensitive data. This arbitrary code execution capability can lead to complete system compromise, data exfiltration, or establishment of persistent backdoors within affected environments. Organizations using OpenText Brava! Desktop should consider this vulnerability as part of broader security assessments, particularly in environments where users frequently handle third-party design files or where the application runs with elevated privileges. The vulnerability's classification as ZDI-CAN-13308 indicates it was recognized by the Zero Day Initiative, highlighting its significance in the cybersecurity community and the need for immediate remediation efforts.
Mitigation strategies should include immediate deployment of vendor-provided patches or updates, implementation of network-based restrictions on DXF file downloads, and user education regarding the dangers of opening untrusted design files. Security teams should also consider deploying application whitelisting solutions that restrict execution of potentially malicious file types and monitor for suspicious file access patterns. The vulnerability underscores the importance of proper input validation and memory safety practices in file processing applications, particularly those handling complex binary formats like DXF that require extensive parsing logic to interpret correctly.