Timing Side-Channel in AES-CCM Tag Verification in AWS-LC

Observable timing discrepancy in AES-CCM decryption in AWS-LC allows an unauthenticated user to potentially determine authentication tag validity via timing analysis. The impacted implementations are through the EVP CIPHER API: EVP_aes_128_ccm, EVP_aes_192_ccm, and EVP_aes_256_ccm. Customers of AWS services do not need to take action. Applications using AWS-LC should upgrade to AWS-LC version 1.69.0.

Observable timing discrepancy in AES-CCM decryption in AWS-LC allows an unauthenticated user to potentially determine authentication tag validity via timing analysis. The impacted implementations are through the EVP CIPHER API: EVP_aes_128_ccm, EVP_aes_192_ccm, and EVP_aes_256_ccm. Customers of AWS services do not need to take action. Applications using AWS-LC should upgrade to AWS-LC version 1.69.0.

Observable timing discrepancy in AES-CCM decryption in AWS-LC allows an unauthenticated user to potentially determine authentication tag validity via timing analysis. The impacted implementations are through the EVP CIPHER API: EVP_aes_128_ccm, EVP_aes_192_ccm, and EVP_aes_256_ccm. Customers of AWS services do not need to take action. Applications using AWS-LC should upgrade to AWS-LC version 1.69.0.

### Summary AWS-LC is an open-source, general-purpose cryptographic library. ### Impact Observable timing discrepancy in AES-CCM decryption in AWS-LC allows an unauthenticated user to potentially determine authentication tag validity via timing analysis. The impacted implementations are through the EVP CIPHER API: EVP_aes_128_ccm, EVP_aes_192_ccm, and EVP_aes_256_ccm. Customers of AWS services do not need to take action. aws-lc-sys and aws-lc-fips-sys contain code from AWS-LC. Applications using aws-lc-sys or aws-lc-fips-sys should upgrade to the most recent releases of aws-lc-sys or aws-lc-fips-sys. ### Impacted versions: - aws-lc-sys versions: >= 0.14.0, < 0.38.0 - aws-lc-fips-sys versions: >= v0.13.0, < 0.13.12. ### Patches The patch is included in aws-lc-sys v.0.38.0 and aws-lc-fips-sys v0.13.12. ### Workarounds In the special cases of using AES-CCM with (M=4, L=2), (M=8, L=2), or (M=16, L=2), applications can workaround this issue by using AES-CCM through the EVP AEAD API using implementations EVP_aead_aes_128_ccm_bluetooth, EVP_aead_aes_128_ccm_bluetooth_8, and, EVP_aead_aes_128_ccm_matter respectively. Otherwise, there is no workaround and applications using aws-lc-sys or aws-lc-fips-sys should upgrade to the most recent releases of aws-lc-sys or aws-lc-fips-sys. ### Resources If there are any questions or comments about this advisory, contact [AWS/Amazon] Security via the[vulnerability reporting page](https://aws.amazon.com/security/vulnerability-reporting) or directly via email to [[email protected]](mailto:[email protected]). Please do not create a public GitHub issue. ### Acknowledgement AWS-LC would like to thank Joshua Rogers (https://joshua.hu/) for collaborating on this issue through the coordinated vulnerability disclosure process.

Observable timing discrepancy in AES-CCM decryption in AWS-LC allows an unauthenticated user to potentially determine authentication tag validity via timing analysis. The impacted implementations are through the EVP CIPHER API: `EVP_aes_128_ccm`, `EVP_aes_192_ccm`, and `EVP_aes_256_ccm`. Customers of AWS services do not need to take action. `aws-lc-fips-sys` contains code from AWS-LC. Applications using `aws-lc-fips-sys` should upgrade to the most recent release of `aws-lc-fips-sys`. ## Workarounds In the special cases of using AES-CCM with (M=4, L=2), (M=8, L=2), or (M=16, L=2), applications can workaround this issue by using AES-CCM through the EVP AEAD API using implementations `EVP_aead_aes_128_ccm_bluetooth`, `EVP_aead_aes_128_ccm_bluetooth_8`, and `EVP_aead_aes_128_ccm_matter` respectively. Otherwise, there is no workaround and applications using `aws-lc-fips-sys` should upgrade to the most recent release of `aws-lc-fips-sys`.

Observable timing discrepancy in AES-CCM decryption in AWS-LC allows an unauthenticated user to potentially determine authentication tag validity via timing analysis. The impacted implementations are through the EVP CIPHER API: `EVP_aes_128_ccm`, `EVP_aes_192_ccm`, and `EVP_aes_256_ccm`. Customers of AWS services do not need to take action. `aws-lc-sys` contains code from AWS-LC. Applications using `aws-lc-sys` should upgrade to the most recent release of `aws-lc-sys`. ## Workarounds In the special cases of using AES-CCM with (M=4, L=2), (M=8, L=2), or (M=16, L=2), applications can workaround this issue by using AES-CCM through the EVP AEAD API using implementations `EVP_aead_aes_128_ccm_bluetooth`, `EVP_aead_aes_128_ccm_bluetooth_8`, and `EVP_aead_aes_128_ccm_matter` respectively. Otherwise, there is no workaround and applications using `aws-lc-sys` should upgrade to the most recent release.