CVE-2024-23680 identifies a vulnerability in the AWS Encryption SDK for Java, specifically in versions 2.0.0 to 2.2.0 and versions below 1.9.0, where the SDK improperly verifies certain ECDSA (Elliptic Curve Digital Signature Algorithm) signatures. This vulnerability falls under CWE-347, which concerns improper verification of cryptographic signatures. The flaw causes the SDK to accept some invalid signatures as valid, undermining the integrity guarantees that digital signatures are intended to provide. The AWS Encryption SDK is widely used to perform client-side encryption and decryption operations, ensuring data confidentiality and integrity before data is sent to or retrieved from cloud storage or services. The incorrect validation means that an attacker could potentially craft a malformed signature that bypasses signature verification, allowing unauthorized data to be accepted as authentic. However, the vulnerability does not affect confidentiality or availability, and exploitation does not require privileges or user interaction, making it a remote and unauthenticated risk. No known exploits have been reported in the wild as of the publication date. The CVSS v3.1 base score is 5.3 (medium), reflecting the limited impact on confidentiality and availability but a clear impact on integrity. The vulnerability is significant in environments where cryptographic signature verification is critical to security, such as in secure messaging, data integrity checks, or authentication mechanisms relying on the AWS Encryption SDK. No official patch links were provided at the time of reporting, so users should monitor AWS advisories for updates or consider alternative mitigations.

For European organizations, the primary impact of CVE-2024-23680 lies in the potential compromise of data integrity when using the affected AWS Encryption SDK for Java versions. This could lead to acceptance of tampered or malicious data as authentic, undermining trust in cryptographic protections. Sectors such as finance, healthcare, and government that rely heavily on cryptographic assurances for regulatory compliance and data protection could face increased risk of data manipulation or fraud. Although confidentiality and availability are not directly impacted, integrity failures can cascade into broader security incidents, including unauthorized transactions or corrupted data processing. The lack of required privileges or user interaction means attackers could exploit this vulnerability remotely if they can supply crafted signatures to vulnerable systems. Given the widespread adoption of AWS cloud services across Europe, especially in countries with strong cloud infrastructure and digital transformation initiatives, the risk is non-negligible. Organizations using the affected SDK versions in production should assess their exposure and prioritize remediation to maintain compliance with data protection regulations such as GDPR, which emphasize data integrity and security.

1. Upgrade the AWS Encryption SDK for Java to a version that addresses CVE-2024-23680 as soon as an official patch or fixed release is available from AWS. 2. Until a patch is available, implement additional cryptographic signature validation layers outside the SDK to verify ECDSA signatures independently, using well-vetted cryptographic libraries. 3. Conduct thorough code audits and penetration testing focusing on cryptographic operations to detect potential misuse or bypass scenarios. 4. Restrict access to systems performing cryptographic operations to trusted networks and authenticated users to reduce exposure to remote exploitation. 5. Monitor AWS security advisories and vulnerability databases for updates or exploit reports related to this CVE. 6. Educate development and security teams about the risks of improper signature verification and enforce secure coding practices around cryptographic functions. 7. Review and enhance logging and alerting mechanisms to detect anomalies in signature verification failures or unexpected data acceptance. 8. For critical applications, consider implementing multi-factor verification of data integrity, such as combining signatures with additional cryptographic proofs or checksums.