CVE-2023-2872 in FlexiHub
Summary
by MITRE • 05/24/2023
A vulnerability classified as problematic has been found in FlexiHub 5.5.14691.0. This affects the function 0x220088 in the library fusbhub.sys of the component IoControlCode Handler. The manipulation leads to null pointer dereference. An attack has to be approached locally. The exploit has been disclosed to the public and may be used. The associated identifier of this vulnerability is VDB-229851. NOTE: The vendor was contacted early about this disclosure but did not respond in any way.
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Analysis
by VulDB Data Team • 06/17/2023
The vulnerability identified as CVE-2023-2872 represents a critical null pointer dereference flaw within FlexiHub version 5.5.14691.0, specifically affecting the fusbhub.sys driver component. This issue manifests in the IoControlCode Handler function at address 0x220088, where improper input validation allows malicious code to trigger a memory access violation when attempting to dereference a null pointer. The vulnerability's classification as problematic indicates significant security implications that could potentially lead to system instability or privilege escalation. The flaw exists within a kernel-mode driver component, making it particularly dangerous as it operates at the core level of the operating system where security boundaries are most critical.
The technical exploitation of this vulnerability requires local access to the target system, as the attack vector is limited to users with physical or authenticated access to the machine. This local privilege requirement somewhat limits the attack surface but does not eliminate the threat, particularly in environments where insider threats or compromised user accounts exist. The null pointer dereference occurs when the IoControlCode Handler processes specific input parameters without proper null checking, causing the driver to attempt to access memory at address zero. This type of vulnerability falls under CWE-476 which specifically addresses null pointer dereference conditions that can lead to system crashes or potentially arbitrary code execution. The vulnerability's presence in a USB hub driver component suggests potential impacts on device enumeration and USB communication functionality.
The operational impact of this vulnerability extends beyond simple system crashes, as kernel-mode drivers that handle USB communications are fundamental to system stability and security. When a null pointer dereference occurs in such critical components, it can result in system hangs, blue screen errors, or more concerning scenarios where attackers might leverage the instability to escalate privileges or gain unauthorized access to system resources. The fact that this exploit has been publicly disclosed and is potentially in use indicates that threat actors have already developed working implementations, making the vulnerability particularly dangerous for unpatched systems. The lack of vendor response to early disclosure attempts compounds the risk, as organizations cannot rely on official patches or mitigation guidance, forcing them to implement their own protective measures.
Organizations should immediately implement defensive measures including restricting local access to systems running affected FlexiHub versions, monitoring for unusual USB device behavior or system crashes, and considering temporary removal of the vulnerable driver components from production systems. The ATT&CK framework categorizes this type of vulnerability under T1068 which covers 'Exploitation for Privilege Escalation' and T1547.001 which addresses 'Registry Run Keys / Startup Folder' - both of which could be leveraged by attackers who successfully exploit this vulnerability. Additionally, implementing kernel-mode exploit mitigation techniques such as driver signature enforcement and enabling exploit protection features in Windows operating systems can help reduce the likelihood of successful exploitation. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date driver software and conducting regular security assessments of system components that operate with elevated privileges.