CVE-2020-1967
HIGH severity · CVSS 7.5 · CWE-476
7.5CVSS HIGH
Summary
Server or client applications that call the SSL_check_chain() function during or after a TLS 1.3 handshake may crash due to a NULL pointer dereference as a result of incorrect handling of the "signature_algorithms_cert" TLS extension. The crash occurs if an invalid or unrecognised signature algorithm is received from the peer. This could be exploited by a malicious peer in a Denial of Service attack. OpenSSL version 1.1.1d, 1.1.1e, and 1.1.1f are affected by this issue. This issue did not affect OpenSSL versions prior to 1.1.1d. Fixed in OpenSSL 1.1.1g (Affected 1.1.1d-1.1.1f).
Impact & exploitability
Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
Confidentiality impactNone
Integrity impactNone
Availability impactHigh
Exploit probability (EPSS)61%
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Recommendation
Apply the vendor fix promptly. Open any affected product above for its exact safe version.
Additional information
- NVD record
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00004.htmlAdvisory
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00011.htmlAdvisory
- http://packetstormsecurity.com/files/157527/OpenSSL-signature_algorithms_cert-Denial-Of-Service.htmlAdvisory
- http://seclists.org/fulldisclosure/2020/May/5Advisory
- http://www.openwall.com/lists/oss-security/2020/04/22/2Advisory
- https://git.openssl.org/gitweb/?p=openssl.git%3Ba=commitdiff%3Bh=eb563247aef3e83dda7679c43f9649270462e5b1
- https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44440Advisory
- https://github.com/irsl/CVE-2020-1967Advisory