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Amazon Linux AMI: CVE-2017-3737: Security patch for openssl (ALAS-2018-1016)

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Amazon Linux AMI: CVE-2017-3737: Security patch for openssl (ALAS-2018-1016)

Severity
4
CVSS
(AV:N/AC:M/Au:N/C:P/I:N/A:N)
Published
12/07/2017
Created
07/25/2018
Added
05/11/2018
Modified
05/03/2019

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.

Solution(s)

  • amazon-linux-upgrade-openssl

References

  • amazon-linux-upgrade-openssl

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