CVE-2019-5517 in ESXi
Summary
by MITRE
VMware ESXi (6.7 before ESXi670-201904101-SG and 6.5 before ESXi650-201903001), Workstation (15.x before 15.0.3 and 14.x before 14.1.6), Fusion (11.x before 11.0.3 and 10.x before 10.1.6) contain multiple out-of-bounds read vulnerabilities in the shader translator. Exploitation of these issues requires an attacker to have access to a virtual machine with 3D graphics enabled. Successful exploitation of these issues may lead to information disclosure or may allow attackers with normal user privileges to create a denial-of-service condition on their own VM. The workaround for these issues involves disabling the 3D-acceleration feature. This feature is not enabled by default on ESXi and is enabled by default on Workstation and Fusion.
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Analysis
by VulDB Data Team • 05/29/2020
The vulnerability CVE-2019-5517 represents a critical out-of-bounds read flaw discovered in VMware's virtualization platforms affecting multiple product lines including ESXi, Workstation, and Fusion. This vulnerability specifically targets the shader translator component responsible for processing graphics rendering operations within virtual machines. The flaw exists in the way the shader translator handles memory operations during graphics processing, creating opportunities for memory access violations that can result in information disclosure or denial-of-service conditions. These vulnerabilities are particularly concerning because they require minimal privileges to exploit, as they can be triggered by normal user accounts within a compromised virtual environment. The vulnerability affects specific versions of VMware products where the 3D graphics acceleration feature is enabled, making it a significant risk for environments that utilize graphical intensive applications within virtual machines.
The technical implementation of this vulnerability stems from improper bounds checking within the shader translation process that occurs when virtual machines utilize 3D graphics acceleration capabilities. When a virtual machine with 3D acceleration enabled processes graphics commands, the shader translator fails to properly validate input data boundaries, leading to memory access violations that can be exploited by malicious actors. This type of vulnerability maps directly to CWE-125, which describes out-of-bounds read conditions in software implementations. The flaw manifests when the graphics processing unit within the virtual machine attempts to translate shader code, causing the system to read memory locations beyond the intended buffer boundaries. The exploitation requires an attacker to have access to a virtual machine with 3D graphics enabled, which is a relatively common configuration in modern virtualized environments where graphical applications are prevalent. The vulnerability's impact is amplified because it can be leveraged to extract sensitive information from memory or cause the virtual machine to crash, effectively creating a denial-of-service condition.
The operational impact of CVE-2019-5517 extends beyond simple system availability concerns to encompass potential information disclosure risks that could compromise the integrity of virtualized environments. Attackers with access to a compromised virtual machine can potentially leverage this vulnerability to extract memory contents that may contain sensitive data, session information, or other confidential artifacts. The vulnerability affects VMware ESXi, Workstation, and Fusion platforms, each with different default configurations that influence the attack surface. ESXi systems do not enable 3D acceleration by default, providing a natural defense against exploitation, while Workstation and Fusion products have 3D acceleration enabled by default, making them more vulnerable without proper configuration. The vulnerability's exploitation potential is further enhanced by the fact that it requires minimal privileges, meaning that even standard user accounts within a compromised VM can trigger the conditions necessary for exploitation. This characteristic aligns with ATT&CK technique T1059.007, which describes the use of command and scripting interpreters in compromised environments.
Organizations should implement several mitigation strategies to address CVE-2019-5517 effectively. The primary recommended workaround involves disabling 3D acceleration features on affected VMware products, particularly in Workstation and Fusion environments where this feature is enabled by default. System administrators should conduct comprehensive inventory audits to identify all affected VMware installations and ensure proper configuration changes are applied across all virtualized environments. The vulnerability affects specific version ranges, requiring targeted patch management efforts to upgrade to patched versions of VMware products. Security teams should also consider implementing network monitoring to detect potential exploitation attempts and establish baseline configurations that disable 3D graphics acceleration for virtual machines that do not require graphical intensive operations. Additionally, organizations should review their virtual machine deployment policies to ensure that 3D acceleration is only enabled when absolutely necessary for legitimate business applications. The remediation process should include thorough testing of patched systems to ensure that legitimate graphical applications continue to function properly while eliminating the vulnerability exposure.