A Lucky 13 timing side channel in mbedtls_ssl_decrypt_buf in library/ssl_msg.c in Trusted Firmware Mbed TLS through 2.23.0 allows an attacker to recover secret key information. This affects CBC mode because of a computed time difference based on a padding length. The issue is fixed in Mbed TLS 2.24.0, 2.16.8 and 2.7.17.
A Lucky 13 timing side channel in mbedtls_ssl_decrypt_buf in library/ssl_msg.c in Trusted Firmware Mbed TLS through 2.23.0 allows an attacker to recover secret key information. This affects CBC mode because of a computed time difference based on a padding length. The issue is fixed in Mbed TLS 2.24.0, 2.16.8 and 2.7.17.
https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2020-09-1
Workaround ========== Users are encouraged to use AEAD ciphersuites (CHACHA20-POLY1305, GCM, CCM) whenever possible, or it they have to use CBC, to enable use of the Encrypt-then-Mac extension on both sides of the connection.
Vulmon