CVE-2024-0565 is a vulnerability identified in the Linux Kernel's SMB Client sub-component, specifically within the receive_encrypted_standard function located in fs/smb/client/smb2ops.c. The root cause is an integer underflow in the length parameter used by the memcpy function. Integer underflow occurs when an arithmetic operation causes a value to wrap around below its minimum representable value, resulting in an unexpectedly large unsigned integer. In this case, the underflow leads to an out-of-bounds memory read during the copying of encrypted SMB2 data. This memory corruption can cause the kernel to crash or behave unpredictably, resulting in a denial of service condition. The vulnerability requires either local or network access with low privileges and user interaction, and has a high attack complexity, meaning exploitation is not trivial. The CVSS v3.1 base score of 6.8 reflects medium severity, with high impact on confidentiality, integrity, and availability, indicating that successful exploitation could lead to significant system compromise. No public exploits or active exploitation have been reported to date. The vulnerability affects all versions of the Linux Kernel that include the vulnerable SMB client code and have not applied patches. Since SMB is widely used for file sharing and network communication, especially in mixed OS environments, this vulnerability poses a risk to systems relying on SMB client functionality.

For European organizations, the impact of CVE-2024-0565 can be substantial, particularly for enterprises and public sector entities that use Linux-based systems for network file sharing via SMB. A successful attack could lead to denial of service, disrupting critical services and operations. The high impact on confidentiality and integrity suggests potential for information leakage or manipulation if the vulnerability is chained with other exploits, although the primary impact is DoS. Organizations with hybrid environments that integrate Linux SMB clients with Windows servers may face increased risk due to SMB’s widespread use. Disruptions could affect sectors such as finance, healthcare, manufacturing, and government, where availability and data integrity are paramount. Additionally, the requirement for user interaction and high attack complexity somewhat limits the immediacy of the threat but does not eliminate risk, especially in environments with untrained users or weak network segmentation.

To mitigate CVE-2024-0565, organizations should prioritize applying official Linux Kernel patches as soon as they become available from trusted distributors or maintainers. Until patches are deployed, restricting SMB client usage on Linux systems can reduce exposure; this includes disabling SMB client functionality where not needed and limiting network access to SMB services through firewall rules and network segmentation. Monitoring kernel logs and system behavior for crashes or anomalies related to SMB client operations can help detect attempted exploitation. Employing endpoint protection solutions that can detect abnormal memory access patterns may provide additional defense. User education to avoid interacting with untrusted SMB shares or links is also important given the requirement for user interaction. Finally, maintaining up-to-date backups and incident response plans will help organizations recover quickly if a denial of service occurs.