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Cisco Bug: CSCvs33392 - Known Key SSL decryption and connections can fail when servers are using unsupported TLS options

Last Modified

Apr 19, 2020

Products (1)

  • Cisco Firepower Management Center

Known Affected Releases

6.3.0 6.4.0 6.5.0 6.6.0

Description (partial)

The TLS protocol continues to add new versions and options. When TLS servers adopt these new versions and options, such as TLS 1.3, that are not yet supported by SSL inspection, Known Key decryption to these servers can fail and even result in broken connections in some cases.

This can occur on all devices that support SSL inspection and where SSL inspection is enabled and Known Key decryption is being performed. Additionally, in order for this to occur, servers that are being decrypted by Known Key decryption must be configured to useTLS versions and/or options that are not supported by SSL inspection.
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