A critical vulnerability was discovered in the ENE UB625 reader driver (drivers/usb/storage/ene_ub625.c) in the Linux kernel versions before 6.2.5. This security vulnerability allows an object to potentially extend beyond the end of an allocation, which could be exploited by attackers to gain unauthorized access, escalate privileges, or execute malicious code.

This post will provide details about this vulnerability, its impact, possible exploit methods, as well as available patches and workarounds. The following sections will explain the underlying issue, references to original sources and code snippets to help better understand the problem.

Detailed Description

The ENE UB625 reader driver, found in the Linux kernel, is responsible for handling USB storage devices. The affected driver file is drivers/usb/storage/ene_ub625.c. The issue stems from a potential scenario in which an object can extend beyond the end of an allocated space, leading to an overflow vulnerability. This highlights a crucial problem in the driver code that, if exploited, can lead to serious security consequences.

The specific code snippet that showcases the vulnerability can be found below

static int ene_read_data(struct ene_ub625_info *srb_info, u16 *data)
{
   ...
   nreg_data = srb_info->in_buff[1] << 8 | srb_info->in_buff[];
   ...
}

In the above code, srb_info is a pointer to a structure containing information about the USB device, and the in_buff variable is an array within this structure that's used to store incoming data from the device. The vulnerability occurs when the 16-bit value (nreg_data) read from the in_buff array is used in a way that leads to an object extending beyond its allocated space. This eventually opens up the possibility of various exploits, including unauthorized access, privilege escalation, or arbitrary code execution.

Original References and Exploit Details

The vulnerability was first reported to the Linux kernel community by a security researcher with the ID CVE-2023-45862. The official record of this vulnerability can be found at the National Vulnerability Database (NVD) here, along with other necessary details.

As of now, there is no publicly available exploit code for this vulnerability. However, this does not mean that the issue should be taken lightly. Attackers can potentially take advantage of similar vulnerabilities to craft their exploits and compromise vulnerable systems.

Patches and Mitigation

To address the vulnerability, the Linux kernel developers have released a fix in the form of a patch, which has been applied to the kernel version 6.2.5 and later. Users running vulnerable versions of the Linux kernel are advised to update their systems to a patched version immediately, either through their Linux distribution's package manager or by downloading and compiling the latest source code from the official Linux kernel website here.

For those unable to update their kernel, a potential workaround is to disable the ENE UB625 reader driver entirely. This can be done in several ways, including recompiling the kernel without the driver support or blacklisting the driver through the modprobe configuration file.

Conclusion

The CVE-2023-45862 vulnerability is a serious issue affecting users running the ENE UB625 reader driver on the Linux kernel versions before 6.2.5. To mitigate the risks associated with this vulnerability, users are recommended to update their kernel to a later version that includes the necessary patches or consider disabling the vulnerable driver if they are unable to update their system.

Timeline

Published on: 10/14/2023 21:15:45 UTC
Last modified on: 11/16/2023 15:15:09 UTC