CVE-2018-6970 in Horizon Client
Summary
by MITRE
VMware Horizon 6 (6.x.x before 6.2.7), Horizon 7 (7.x.x before 7.5.1), and Horizon Client (4.x.x and prior before 4.8.1) contain an out-of-bounds read vulnerability in the Message Framework library. Successfully exploiting this issue may allow a less-privileged user to leak information from a privileged process running on a system where Horizon Connection Server, Horizon Agent or Horizon Client are installed. Note: This issue doesn't apply to Horizon 6, 7 Agents installed on Linux systems or Horizon Clients installed on non-Windows systems.
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Analysis
by VulDB Data Team • 05/01/2023
The vulnerability identified as CVE-2018-6970 represents a critical out-of-bounds read flaw within VMware Horizon's Message Framework library component. This security weakness affects multiple versions of VMware Horizon 6, Horizon 7, and Horizon Client applications across Windows platforms, specifically targeting systems where the connection server, agent, or client components are deployed. The issue stems from improper input validation mechanisms within the message processing framework that fails to adequately bounds-check data structures during message handling operations. The vulnerability is particularly concerning because it enables information disclosure from privileged processes, creating a potential attack vector for adversaries seeking to escalate their privileges or extract sensitive system information.
The technical exploitation of this vulnerability occurs through crafted messages or data inputs that cause the Message Framework library to access memory locations beyond the intended buffer boundaries. This out-of-bounds read condition allows a low-privileged user to potentially access memory contents that should remain restricted to higher-privilege processes. The flaw exists in the message handling routines where the system does not properly validate the size or content of incoming messages before processing them, leading to memory corruption that can reveal sensitive information such as memory addresses, system configurations, or other confidential data from the privileged processes. This type of vulnerability maps directly to CWE-125, which specifically addresses out-of-bounds read conditions in software implementations.
The operational impact of CVE-2018-6970 extends beyond simple information disclosure, as it creates opportunities for more sophisticated attacks within VMware Horizon environments. Attackers can leverage this vulnerability to gather intelligence about system configurations, memory layouts, and potentially identify other weaknesses in the system architecture. The privilege escalation potential arises because the leaked information could be used to bypass security controls or understand the internal workings of privileged processes. This vulnerability is particularly dangerous in enterprise environments where Horizon is used for remote desktop and application delivery services, as it could enable attackers to gain insights into the underlying infrastructure and potentially compromise the security posture of the entire virtual desktop infrastructure. According to ATT&CK framework, this vulnerability aligns with techniques involving information gathering and privilege escalation through memory corruption.
Mitigation strategies for CVE-2018-6970 primarily focus on applying vendor-provided patches and updates to affected VMware Horizon components. Organizations should immediately upgrade to the patched versions of Horizon 6 (6.2.7), Horizon 7 (7.5.1), and Horizon Client (4.8.1) to address the root cause of the vulnerability. Network segmentation and access controls should be implemented to limit exposure of Horizon components to untrusted networks, reducing the attack surface. Additionally, monitoring systems should be configured to detect unusual message patterns or attempts to exploit the vulnerability through log analysis and behavioral monitoring. Security teams should also consider implementing application whitelisting policies to restrict execution of unauthorized code that might attempt to exploit similar memory corruption vulnerabilities. Regular security assessments and vulnerability scanning should be conducted to identify any other potentially affected components within the VMware Horizon ecosystem that might present similar security risks.