CVE-2017-4902 in ESXi
Summary
by MITRE
VMware ESXi 6.5 without patch ESXi650-201703410-SG and 5.5 without patch ESXi550-201703401-SG; Workstation Pro / Player 12.x prior to 12.5.5; and Fusion Pro / Fusion 8.x prior to 8.5.6 have a Heap Buffer Overflow in SVGA. This issue may allow a guest to execute code on the host.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 12/26/2020
The vulnerability identified as CVE-2017-4902 represents a critical heap buffer overflow flaw within VMware ESXi hypervisor versions 6.5 and 5.5, as well as in VMware Workstation Pro/Player 12.x and Fusion Pro/8.x products. This vulnerability specifically affects the SVGA (Simple Virtual Graphics Adapter) component that handles graphics operations within virtualized environments. The flaw arises from insufficient bounds checking when processing graphics commands from guest operating systems, creating an exploitable condition that can be leveraged by malicious actors to execute arbitrary code on the host system. The vulnerability impacts organizations running these specific VMware products without the corresponding security patches, which were released in March 2017 to address this precise issue.
The technical implementation of this heap buffer overflow occurs within the SVGA subsystem where guest applications send graphics-related commands to the hypervisor. When these commands contain malformed data or exceed expected buffer sizes, the memory management routines fail to properly validate input parameters, leading to memory corruption. This memory corruption can be exploited to overwrite critical memory locations, potentially allowing attackers to inject and execute malicious code with the privileges of the host system. The vulnerability is particularly dangerous because it enables privilege escalation from guest-level execution to host-level execution, effectively breaking the isolation boundary that separates virtual machines from the physical host. According to CWE classification, this represents a classic heap-based buffer overflow vulnerability (CWE-119) that falls under the broader category of memory safety issues (CWE-787), while the attack vector aligns with techniques described in the MITRE ATT&CK framework under privilege escalation and execution phases.
The operational impact of CVE-2017-4902 extends beyond simple exploitation, as it fundamentally compromises the security model of virtualized environments. Organizations utilizing affected VMware products face significant risks including complete host compromise, data exfiltration, and potential lateral movement within their network infrastructure. The vulnerability affects organizations of all sizes, from small businesses using VMware Workstation to large enterprises running ESXi hypervisors in production environments. Security teams must consider that a single compromised virtual machine could potentially provide attackers with access to the entire host system and all other virtual machines running on that host, creating a cascading security failure. The exploitability of this vulnerability is relatively high, as it requires minimal privileges within the guest operating system to trigger the condition, making it particularly dangerous in multi-tenant environments where guest isolation is paramount for security.
Mitigation strategies for CVE-2017-4902 primarily focus on applying the vendor-provided patches that address the heap buffer overflow in the SVGA component. Organizations should immediately deploy the ESXi650-201703410-SG patch for ESXi 6.5 systems and ESXi550-201703401-SG for ESXi 5.5 systems, while also updating VMware Workstation Pro/Player to version 12.5.5 and Fusion Pro/8.x to version 8.5.6. Beyond patch management, security teams should implement network segmentation and monitoring to detect potential exploitation attempts, as the vulnerability may be used in conjunction with other attack vectors. The implementation of micro-segmentation within virtualized environments can help limit the impact if exploitation occurs, while regular security assessments and vulnerability scanning should be conducted to identify unpatched systems. Additionally, organizations should consider implementing hypervisor hardening measures, including disabling unnecessary services and features, and establishing robust monitoring for unusual graphics-related processes or memory access patterns that could indicate exploitation attempts.