CVE-2021-31500 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 DWF files. The issue results from the lack of proper validation of a user-supplied value prior to dereferencing it as a pointer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-12746.
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Analysis
by VulDB Data Team • 06/18/2021
The vulnerability identified as CVE-2021-31500 represents a critical remote code execution flaw in OpenText Brava! Desktop version 16.6.3.84, classified under CWE-476 as NULL Pointer Dereference. This security weakness stems from insufficient input validation during the processing of DWF (Document Workspace Format) files, which are commonly used for document rendering and manipulation within the application. The vulnerability specifically manifests when the software attempts to dereference a user-supplied pointer value without proper validation, creating an exploitable condition that can be leveraged by remote attackers.
The technical exploitation of this vulnerability requires user interaction through either visiting a malicious webpage or opening a crafted malicious file containing the vulnerable DWF format. This attack vector aligns with ATT&CK technique T1203 - Exploitation for Client Execution, where adversaries gain access to execute malicious code on target systems. The flaw occurs during the parsing phase of DWF files when the application fails to validate the integrity of pointer references within the file structure, allowing an attacker to manipulate memory access patterns and potentially execute arbitrary code with the privileges of the current process. The vulnerability's classification as a NULL pointer dereference indicates that the application does not properly check for null values before attempting to access memory locations.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with full control over the affected system's processes and potentially enables further escalation within the network environment. Attackers can leverage this weakness to install backdoors, steal sensitive data, or establish persistent access to the compromised system. The fact that user interaction is required for exploitation provides some defense-in-depth opportunities but does not eliminate the severity of the threat, particularly in environments where users may encounter malicious content through email attachments or web browsing activities. Organizations utilizing OpenText Brava! Desktop in enterprise environments face significant risk exposure given that this vulnerability can be exploited remotely without requiring authentication.
Mitigation strategies for CVE-2021-31500 should include immediate patching of affected OpenText Brava! Desktop installations to the latest available version that addresses this specific vulnerability. System administrators should implement network segmentation and monitoring to detect suspicious file access patterns and web traffic that might indicate exploitation attempts. Additionally, user education programs should emphasize the importance of avoiding untrusted file downloads and suspicious web content, particularly when working with document rendering applications. The vulnerability's nature suggests that implementing strict input validation controls and memory access restrictions could provide additional protection layers. Organizations should also consider deploying application whitelisting solutions to prevent execution of unauthorized code and maintain detailed audit logs of file access activities for forensic analysis purposes. The ZDI-CAN-12746 reference indicates this vulnerability was tracked by the Zero Day Initiative, highlighting its significance in the cybersecurity community and the importance of timely patch management.