OpenSSL 1.0.2n patched two vulnerabilities discovered by a Google researcher, said officials at the OpenSSL Project.
The issues ended up discovered by Google’s David Benjamin using Google’s OSS-Fuzz fuzzing service.
One of the vulnerabilities relates to an “error state” mechanism introduced with OpenSSL 1.0.2b.
The mechanism should trigger an immediate failure if there is an attempt to continue a handshake after a fatal error has occurred. The problem is that if the SSL_read() or SSL_write() functions are called directly, the mechanism doesn’t work properly.
“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,” OpenSSL said in an advisory.
This vulnerability has only been rated “moderate severity” due to the fact the targeted application would need to have a bug that causes a call to SSL_read() or SSL_write() after getting a fatal error.
Another vulnerability reported to the OpenSSL Project by Benjamin is an overflow bug that could allow an attacker to access TLS-protected communications. However, an attack is very difficult to carry out, which is why the issue has been classified as “low severity.”
This is the fourth OpenSSL update from 2017 that patches security bugs.