CVE-2017-4937 in Workstation
Summary
by MITRE
VMware Workstation (12.x before 12.5.8) and Horizon View Client for Windows (4.x before 4.6.1) contain an out-of-bounds read vulnerability in JPEG2000 parser in the TPView.dll. On Workstation, this may allow a guest to execute code or perform a Denial of Service on the Windows OS that runs Workstation. In the case of a Horizon View Client, this may allow a View desktop to execute code or perform a Denial of Service on the Windows OS that runs the Horizon View Client. Exploitation is only possible if virtual printing has been enabled. This feature is not enabled by default on Workstation but it is enabled by default on Horizon View Client.
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Analysis
by VulDB Data Team • 01/24/2021
The vulnerability identified as CVE-2017-4937 represents a critical out-of-bounds read flaw within the JPEG2000 parser implementation in VMware's TPView.dll component. This issue affects multiple VMware products including Workstation versions 12.x prior to 12.5.8 and Horizon View Client versions 4.x prior to 4.6.1, demonstrating the widespread impact of improper input validation in multimedia processing libraries. The vulnerability stems from insufficient bounds checking when parsing JPEG2000 image files, specifically within the TPView.dll library that handles image rendering for virtualized environments. This flaw operates at the intersection of multimedia processing and virtualization security, creating potential attack vectors that leverage the parsing of image data within virtualized desktop environments.
The technical execution of this vulnerability requires exploitation through virtual printing functionality, which serves as the attack surface for malicious payload delivery. When virtual printing is enabled, the system processes JPEG2000 image data through the vulnerable TPView.dll parser, allowing attackers to craft specially malformed image files that trigger the out-of-bounds read condition. This condition can manifest as either arbitrary code execution within the host operating system context or denial of service attacks that crash the target system. The vulnerability's impact is amplified by the default enablement of virtual printing in Horizon View Client, making this attack vector particularly dangerous for enterprise environments where remote desktop services are commonly deployed. The flaw aligns with CWE-125, which specifically addresses out-of-bounds read vulnerabilities, and represents a classic example of how image parsing libraries can become attack vectors in virtualized environments.
The operational implications of CVE-2017-4937 extend beyond simple privilege escalation or system compromise, as it enables attackers to potentially execute arbitrary code within the host operating system while running virtualized desktop environments. This capability allows threat actors to bypass traditional security boundaries between guest and host systems, creating a significant escalation path for attackers who have already gained access to a virtualized desktop environment. The vulnerability's exploitation requires specific conditions including the presence of virtual printing functionality and the ability to inject malicious image data into the target environment, making it suitable for targeted attacks rather than widespread automated exploitation. Attackers could leverage this vulnerability through various delivery mechanisms including malicious documents, web-based attacks, or compromised virtual desktop images, with the potential to establish persistent access to corporate networks through compromised virtual desktop infrastructure.
Mitigation strategies for CVE-2017-4937 should focus on immediate patching of affected VMware products to version 12.5.8 or later for Workstation and 4.6.1 or later for Horizon View Client, as these releases contain the necessary fixes for the JPEG2000 parser implementation. Organizations should also consider disabling virtual printing functionality where it is not required for business operations, particularly in Horizon View Client deployments where this feature is enabled by default. Network segmentation and monitoring for unusual image processing activities can provide additional layers of defense, while security teams should implement strict access controls for virtual desktop environments to limit potential attack surfaces. The vulnerability's classification under the ATT&CK framework as a privilege escalation or code execution technique highlights the need for comprehensive endpoint protection and monitoring solutions that can detect anomalous behavior in virtualized environments. Regular security assessments of virtual desktop infrastructure should include verification of default configurations and proper patch management procedures to prevent exploitation of similar vulnerabilities in the future.