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CVE-2017-3737 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 wo...

MediumCVSS 5.9 EPSS 78.7%
Published
Updated
Exploit status
No public exploit known
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Description

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.

Affected products

ProductAffected versionsFixed in
debian/openssl(Debian:12) < 1.1.0b-2 1.1.0b-2
debian/openssl(Debian:13) < 1.1.0b-2 1.1.0b-2
debian/openssl(Debian:14) < 1.1.0b-2 1.1.0b-2
OpenSSL = 1.0.2b No fix listed
OpenSSL = 1.0.2c No fix listed
OpenSSL = 1.0.2d No fix listed
OpenSSL = 1.0.2e No fix listed
OpenSSL = 1.0.2f No fix listed
OpenSSL = 1.0.2g No fix listed
OpenSSL = 1.0.2h No fix listed
OpenSSL = 1.0.2i No fix listed
OpenSSL = 1.0.2j No fix listed
OpenSSL = 1.0.2k No fix listed
OpenSSL = 1.0.2l No fix listed
OpenSSL = 1.0.2m No fix listed
debian linux = 9.0 No fix listed
alpine/openssl(Alpine:v3.3) < 1.0.2n-r0 1.0.2n-r0
alpine/openssl(Alpine:v3.4) < 1.0.2n-r0 1.0.2n-r0
alpine/openssl(Alpine:v3.5) < 1.0.2n-r0 1.0.2n-r0
alpine/openssl(Alpine:v3.6) < 1.0.2n-r0 1.0.2n-r0
alpine/openssl(Alpine:v3.7) < 1.0.2n-r0 1.0.2n-r0
alpine/openssl(Alpine:v3.8) < 1.0.2n-r0 1.0.2n-r0
OpenSSL = 1.0.2b-1.0.2m No fix listed

References