Out-of-Bound Vmalloc Access in imageblit - Kernel
Summary
GSD-2021-1001567: tty: Fix out-of-bound vmalloc access in imageblit. Affects Kernel versions < 8a6a240f52e14356386030d8958ae8b1761d2325. No fix is published. How to fix ↓
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Background
The Kernel is a critical component of the Linux operating system that provides core functionalities and acts as an interface between hardware and software. It manages system resources, facilitates communication between processes, and handles device drivers. The vulnerability in focus involves an out-of-bound vmalloc access in the imageblit function of the tty subsystem. This function is responsible for copying image data to the screen buffer. The vulnerability allows an attacker to access memory beyond the allocated buffer, potentially leading to information disclosure or privilege escalation.
Vulnerability Detail
The vulnerability arises due to improper bounds checking in the imageblit function of the tty subsystem. By providing specially crafted input, an attacker can trigger an out-of-bound access to vmalloc memory. This can result in reading sensitive data from kernel memory or modifying critical data structures, leading to a variety of security issues. The impact and attack plausibility of this vulnerability have not been proven yet, but it is crucial to address it to prevent potential exploitation.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
As a workaround, users can apply patches provided by the Linux Kernel community to address the vulnerability. These patches modify the affected code to ensure proper bounds checking and prevent out-of-bound vmalloc access. It is recommended to consult the official Linux Kernel mailing list or security advisories for the specific patch corresponding to this vulnerability.
Conclusion
The out-of-bound vmalloc access vulnerability in the imageblit function of the tty subsystem in the Kernel can have serious security implications. It is crucial to update the Kernel to the fixed version (v4.19.209) or apply the provided patches to mitigate the risk. Regularly monitoring for vulnerabilities using tools like Vulert can help ensure the timely identification and remediation of such issues. For further support on vulnerability remediation, you can reach out to DevNack.com.
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FAQ
The impact of this vulnerability can vary depending on the attacker's capabilities and the specific context of the system. However, potential consequences include information disclosure, privilege escalation, and the ability to manipulate critical data structures.
You can use tools like Vulert to check if your system is affected by this vulnerability. Vulert analyzes package manifests, such as package-lock.json, to identify and alert in real-time for open-source vulnerabilities. You can visit the Vulert playground at Vulert Scanner to check if your application is affected without requiring any signup.
At the time of this report, no known exploits for this vulnerability have been disclosed. However, it is crucial to address the vulnerability promptly to mitigate potential risks.
The exact conditions for remote exploitation of this vulnerability are not yet known. However, it is always recommended to apply security patches and updates as soon as they become available to minimize the risk of remote exploitation.
For more details about this vulnerability, you can refer to the source information provided by the Cloud Security Alliance's GSD database. The link to the specific vulnerability entry is available in the database-specific section of this report.
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