CVE-2023-53059 is a vulnerability identified in the Linux kernel, specifically within the Chrome OS Embedded Controller (EC) character device driver component (cros_ec_chardev). The flaw arises from improper handling of the ioctl interface used to communicate with the EC host commands. When a user-space process invokes these commands, it provides a structure cros_ec_command that includes an 'insize' field indicating the size of input data. Due to insufficient validation or improper memory initialization, it is possible for an attacker to specify a larger 'insize' value than the actual buffer size, causing the kernel to leak residual kernel memory contents back to user space. This results in an information disclosure vulnerability where sensitive kernel data can be read by unauthorized users. The root cause is the failure to zero out the memory before copying data back to user space, allowing leftover kernel data to be exposed. The fix implemented involves zeroing the memory buffer before use, preventing leakage of unintended data. This vulnerability affects Linux kernel versions containing the vulnerable cros_ec_chardev code prior to the patch. Although no known exploits are reported in the wild, the flaw represents a direct kernel memory disclosure vector via a character device interface, which is typically accessible to local users or processes with some privileges. The vulnerability does not require complex exploitation techniques but does require the ability to invoke the ioctl on the cros_ec_chardev device, which may be restricted to certain user groups or processes depending on system configuration. Given the Linux kernel's widespread use across numerous distributions and devices, especially in Chrome OS and embedded systems, this vulnerability has a broad potential impact surface. However, it is limited to systems running the affected kernel versions with the vulnerable EC driver enabled.

For European organizations, the impact of CVE-2023-53059 primarily concerns confidentiality breaches through kernel memory disclosure. Attackers able to exploit this flaw could gain access to sensitive kernel data, which might include cryptographic keys, passwords, or other security-critical information residing in kernel memory. This could facilitate further privilege escalation or lateral movement within affected systems. Organizations using Chrome OS devices or Linux-based embedded systems with the vulnerable kernel versions are at risk. The vulnerability could undermine trust in device integrity and confidentiality, particularly in sectors handling sensitive data such as finance, healthcare, and government. Additionally, organizations deploying Linux servers or workstations with the affected kernel versions may face increased risk if local users or compromised accounts can exploit this flaw to leak kernel memory. While remote exploitation is unlikely without local access, insider threats or malware with local execution capabilities could leverage this vulnerability. The absence of known exploits in the wild reduces immediate risk but does not eliminate the threat, especially as attackers may develop exploits once the vulnerability details are public. The impact is heightened in environments with shared access or multi-tenant systems where kernel memory leakage could expose data across user boundaries.

To mitigate CVE-2023-53059, European organizations should prioritize updating their Linux kernels to the latest patched versions that include the fix for the cros_ec_chardev ioctl memory leak. Kernel upgrades should be tested and deployed promptly, especially on Chrome OS devices and embedded Linux systems. System administrators should audit device permissions to restrict access to the cros_ec_chardev character device, ensuring only trusted users and processes can invoke ioctl commands. Employing mandatory access controls (e.g., SELinux, AppArmor) to limit access to the EC device interface can reduce exploitation risk. Monitoring and logging ioctl invocations on the cros_ec_chardev device may help detect anomalous usage patterns indicative of exploitation attempts. For environments where immediate kernel updates are not feasible, consider disabling or restricting the EC character device if it is not essential for system operation. Additionally, organizations should maintain strong endpoint security controls to prevent local privilege escalation and malware infections that could leverage this vulnerability. Regular vulnerability scanning and patch management processes should include checks for this specific kernel flaw. Finally, educating users and administrators about the risks of local privilege misuse can help reduce exploitation likelihood.