CVE-2024-43815 is a vulnerability identified in the Linux kernel's cryptographic subsystem, specifically within the mxs-dcp driver responsible for hardware-accelerated AES encryption using key slots. The flaw arises because the payload field is not properly zeroed out when AES operations utilize keys stored in hardware key slots. This improper handling can lead to leakage of stack memory contents through the payload field during encryption operations. The vulnerability does not affect scenarios where keys are supplied from main memory via the descriptor payload, which is the common use case. The root cause is that when the hardware key slot is used, the payload field may contain residual stack data, potentially exposing sensitive information. The Linux kernel maintainers have addressed this issue by ensuring the payload field is explicitly zeroed in these cases, preventing unintended data leakage. No known exploits are reported in the wild at this time, and the vulnerability was published on August 17, 2024. The affected versions are identified by specific commit hashes, indicating this is a recent and targeted fix in the kernel source code.

For European organizations, this vulnerability poses a risk primarily related to confidentiality breaches. If exploited, an attacker with the ability to trigger AES encryption operations using hardware key slots could potentially extract sensitive stack memory data, which might include cryptographic keys, passwords, or other critical information residing temporarily in memory. Although exploitation requires the use of hardware key slots, which may not be the default configuration in many environments, organizations utilizing hardware-accelerated cryptographic modules in Linux systems could be at risk. The impact is heightened in sectors relying heavily on Linux-based infrastructure for secure communications, such as finance, government, and critical infrastructure. However, since the vulnerability does not affect the common use case of keys supplied from main memory, the scope of impact is somewhat limited. The absence of known exploits reduces immediate risk but does not eliminate the potential for future attacks. Confidentiality compromise could lead to further lateral movement or privilege escalation within affected networks.

European organizations should prioritize updating their Linux kernel to the patched version that includes the fix for CVE-2024-43815. Specifically, kernel versions incorporating the commit that zeroes the payload field when using hardware key slots should be deployed. Organizations using hardware cryptographic accelerators should audit their systems to determine if hardware key slots are in use and assess exposure accordingly. If hardware key slots are not used, the risk is minimal, but patching remains recommended to prevent future exploitation. Additionally, organizations should implement strict access controls to limit which users or processes can invoke cryptographic operations with hardware keys. Monitoring and logging cryptographic operations may help detect anomalous usage patterns. Finally, security teams should stay alert for any emerging exploit reports and apply security advisories promptly.