OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an error state 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.
The product reads data past the end, or before the beginning, of the intended buffer.
Name | Vendor | Start Version | End Version |
---|---|---|---|
Openssl | Openssl | 1.0.2b (including) | 1.0.2b (including) |
Openssl | Openssl | 1.0.2c (including) | 1.0.2c (including) |
Openssl | Openssl | 1.0.2d (including) | 1.0.2d (including) |
Openssl | Openssl | 1.0.2e (including) | 1.0.2e (including) |
Openssl | Openssl | 1.0.2f (including) | 1.0.2f (including) |
Openssl | Openssl | 1.0.2g (including) | 1.0.2g (including) |
Openssl | Openssl | 1.0.2h (including) | 1.0.2h (including) |
Openssl | Openssl | 1.0.2i (including) | 1.0.2i (including) |
Openssl | Openssl | 1.0.2j (including) | 1.0.2j (including) |
Openssl | Openssl | 1.0.2k (including) | 1.0.2k (including) |
Openssl | Openssl | 1.0.2l (including) | 1.0.2l (including) |
Openssl | Openssl | 1.0.2m (including) | 1.0.2m (including) |