CVE-2020-24489 in Intel
Summary
by MITRE • 06/10/2021
Incomplete cleanup in some Intel(R) VT-d products may allow an authenticated user to potentially enable escalation of privilege via local access.
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Analysis
by VulDB Data Team • 06/12/2021
The vulnerability identified as CVE-2020-24489 resides within Intel(R) Virtualization Technology for Directed I/O products, specifically addressing issues related to incomplete cleanup operations within the VT-d subsystem. This flaw affects systems utilizing Intel's virtualization technology for device assignment and I/O virtualization, where the hypervisor or operating system fails to properly clean up certain memory mappings or device states during virtual machine transitions or system operations. The vulnerability is classified under CWE-676 as the use of potentially dangerous functions, specifically referencing improper resource management during virtualization operations that can lead to privilege escalation.
The technical implementation of this vulnerability stems from inadequate memory management practices within Intel's VT-d implementation where device context tables and interrupt remapping tables are not properly cleared or invalidated when virtual machines are migrated, destroyed, or when system resources are reallocated. This incomplete cleanup allows an authenticated local user to potentially exploit the residual state information to gain elevated privileges. The flaw manifests when the system fails to properly invalidate or reset device-specific memory mappings that could contain sensitive information or access permissions that should not persist across virtual machine boundaries.
From an operational perspective, this vulnerability presents a significant risk to cloud computing environments, virtualized infrastructure, and systems utilizing Intel VT-d for device passthrough operations. Attackers with local access to a system can potentially leverage this flaw to escalate their privileges from a standard user to administrator or root level access, depending on the specific implementation and system configuration. The impact extends beyond simple privilege escalation as it can enable further attacks such as hypervisor compromise, data exfiltration, or lateral movement within virtualized environments where VT-d is actively used for device assignment and I/O virtualization.
Mitigation strategies for CVE-2020-24489 primarily involve applying firmware updates from Intel that address the incomplete cleanup behaviors within VT-d implementations. System administrators should also implement strict access controls and monitoring for local user activities, particularly in virtualized environments where VT-d is enabled. The vulnerability aligns with ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation' and may also relate to T1499 which covers 'Endpoint Denial of Service' through potential resource exhaustion or system instability. Organizations should also consider disabling VT-d features when not required, implementing comprehensive system monitoring, and maintaining updated security patches to prevent exploitation of this class of vulnerability. Additionally, security teams should perform regular vulnerability assessments and penetration testing to identify potential exploitation vectors that could leverage this privilege escalation flaw in their specific environments.