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.
History

No history.

cve-icon MITRE

Status: PUBLISHED

Assigner: openssl

Published: 2017-12-07T16:00:00Z

Updated: 2024-09-17T03:53:31.262Z

Reserved: 2016-12-16T00:00:00

Link: CVE-2017-3737

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2017-12-07T16:29:00.193

Modified: 2019-10-03T00:03:26.223

Link: CVE-2017-3737

cve-icon Redhat

Severity : Moderate

Publid Date: 2017-12-07T00:00:00Z

Links: CVE-2017-3737 - Bugzilla