In the Linux kernel, a vulnerability has been identified related to a race condition between the usb gadget functionality. Specifically, the race condition occurs between the functions gether_disconnect() and eth_stop(), leading to a NULL pointer dereference.
The vulnerability arises when eth_stop() is triggered concurrently while the gether_disconnect() function is in the process of tearing down endpoints.
Due to this race condition, eth_stop() attempts to access a cleared endpoint descriptor, resulting in a crash and potential hard lockup. This can affect system stability, particularly in environments relying on USB functionalities.
Organizations should prioritize monitoring their systems and be prepared for patches addressing this vulnerability, as it poses risks even in low-exploitation scenarios.
Vulnerability Details
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: u_ether: Fix race between gether_disconnect and eth_stop.
A race condition between gether_disconnect() and eth_stop() leads to a NULL pointer dereference. Specifically, if eth_stop() is triggered concurrently while gether_disconnect() is tearing down the endpoints, eth_stop() attempts to access the cleared endpoint descriptor, causing a NPE.
Because eth_stop() crashes while holding the dev->lock, the thread running gether_disconnect() fails to acquire the same lock and spins forever, resulting in a hardlockup.
The root cause is that the clearing of dev->port_usb in gether_disconnect() is delayed until the end of the function. Moving the clearing of dev->port_usb to the very beginning of gether_disconnect() while holding dev->lock addresses this issue.
Technical Analysis
The root cause of this vulnerability stems from a race condition that occurs within the Linux kernel’s USB gadget subsystem. When gether_disconnect() is called, it is responsible for tearing down the endpoint descriptors. If, at the same time, eth_stop() is executed, it attempts to access the endpoint descriptor that has already been cleared. This results in a NULL pointer dereference, leading to a crash of the eth_stop() function.
The attack vector is local, as this vulnerability requires direct access to the affected system for exploitation. The complexity of exploiting this vulnerability is assessed as low, as it could be triggered by concurrent operations within the kernel.
No user interaction is required to exploit this vulnerability, as it can be executed automatically by the kernel processes themselves. The impacts on confidentiality, integrity, and availability are significant, as a successful exploitation could lead to a system crash and denial of service.
Risk & Impact Analysis
Risk to organizations includes potential system crashes and denial of service due to the hard lockup caused by this vulnerability. The exploitation of this vulnerability could lead to significant downtime and interruptions in services relying on USB functionalities.
Organizations should address this vulnerability within their routine maintenance cycles, as the exploitability is low and currently not active in the wild. However, proactive monitoring for patches and updates is recommended to ensure systems remain secure.
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions prior to vendor patch.
Mitigation & Remediation
To mitigate this vulnerability, organizations should apply the latest patches from the Linux kernel maintainers as they become available. If a patch is unavailable, consider implementing network controls to limit access to affected systems.
For ongoing protection, organizations can implement continuous security testing practices, and ensure their systems are monitored for unusual behavior that could indicate exploitation attempts.
Detection Guidance
Security teams should monitor logs for indicators of unusual disconnections or failures in USB operations. Behavioral anomalies during device connections, as well as unexpected system crashes or lockups, should also be flagged for further investigation.
AppSecure Threat Intelligence Insight
This vulnerability highlights the importance of robust testing and review processes within the Linux kernel development lifecycle. Security teams should prioritize understanding and mitigating race conditions, as they can often lead to severe disruptions in system functionality.
For in-depth analysis, organizations may consider leveraging professional penetration testing services to evaluate their security posture against potential vulnerabilities, including those stemming from race conditions.
Proactive approaches, such as the implementation of a comprehensive vulnerability management program, can significantly enhance the resilience of systems against such vulnerabilities.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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