Description
The TLS protocol 1.2 and earlier supports the rsa_fixed_dh, dss_fixed_dh, rsa_fixed_ecdh, and ecdsa_fixed_ecdh values for ClientCertificateType but does not directly document the ability to compute the master secret in certain situations with a client secret key and server public key but not a server secret key, which makes it easier for man-in-the-middle attackers to spoof TLS servers by leveraging knowledge of the secret key for an arbitrary installed client X.509 certificate, aka the "Key Compromise Impersonation (KCI)" issue.
Metrics
CVSS 3.1 8.1/10
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HWeakness enumeration
Affected software
| Vendor | Product | Versions |
|---|---|---|
| n/a | n/a | n/a |
References
- http://twitter.com/matthew_d_green/statuses/630908726950674433Press/Media Coverage, Technical Description, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2016/09/20/4Mailing List, Technical Description, Third Party Advisory
- http://www.securityfocus.com/bid/93071Broken Link, Third Party Advisory, VDB Entry
- https://kcitls.orgExploit, Technical Description
- https://security.netapp.com/advisory/ntap-20180626-0002/Third Party Advisory
- https://www.usenix.org/system/files/conference/woot15/woot15-paper-hlauschek.pdfExploit, Mitigation, Technical Description
- http://twitter.com/matthew_d_green/statuses/630908726950674433Press/Media Coverage, Technical Description, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2016/09/20/4Mailing List, Technical Description, Third Party Advisory
- http://www.securityfocus.com/bid/93071Broken Link, Third Party Advisory, VDB Entry
- https://kcitls.orgExploit, Technical Description
- https://security.netapp.com/advisory/ntap-20180626-0002/Third Party Advisory
- https://www.usenix.org/system/files/conference/woot15/woot15-paper-hlauschek.pdfExploit, Mitigation, Technical Description
Timeline
- Published
- Sep 21, 2016
- Last modified
- Jun 17, 2026
- NVD status
- Modified