OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an errorstate mechanism. The intent was that if a fatal error occurred during a handshake then OpenSSL would move into the error state and would immediately fail if you attempted to continue the handshake. This works as designed for the explicit handshake functions (SSL_do_handshake(), SSL_accept() and SSL_connect()), however due to a bug it does not work correctly if SSL_read() or SSL_write() is called directly. In that scenario, if the handshake fails then a fatal error will be returned in the initial function call. If SSL_read()/SSL_write() is subsequently called by the application for the same SSL object then it will succeed and the data is passed without being decrypted/encrypted directly from the SSL/TLS record layer. In order to exploit this issue an application bug would have to be present that resulted in a call to SSL_read()/SSL_write() being issued after having already received a fatal error. OpenSSL version 1.0.2b-1.0.2m are affected. Fixed in OpenSSL 1.0.2n. OpenSSL 1.1.0 is not affected.
NOTE: The following CVSS v2.0 metrics and score provided are preliminary and subject to review.
|Base Score:||4.3||Base Metrics:||AV:N/AC:M/Au:N/C:P/I:N/A:N|
|Access Vector:||Network||Attack Complexity:||Medium|
|Authentication:||None required||Confidentiality Impact:||Partial|
|Integrity Impact:||None||Availability Impact:||None|
|Oracle Linux version 7 (openssl)||ELSA-2018-0998||2018-04-16|
This page is generated automatically and has not been checked for errors or omissions. For clarification or corrections please contact the Oracle Linux ULN team