CVE-2020-1967

MEDIUM

Description

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).

References

http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00004.html

http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00011.html

http://packetstormsecurity.com/files/157527/OpenSSL-signature_algorithms_cert-Denial-Of-Service.html

http://seclists.org/fulldisclosure/2020/May/5

http://www.openwall.com/lists/oss-security/2020/04/22/2

https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=eb563247aef3e83dda7679c43f9649270462e5b1

https://github.com/irsl/CVE-2020-1967

https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44440

https://lists.apache.org/thread.html/[email protected]%3Cdev.tomcat.apache.org%3E

https://lists.apache.org/thread.html/[email protected]%3Cdev.tomcat.apache.org%3E

https://lists.apache.org/thread.html/[email protected]%3Cdev.tomcat.apache.org%3E

https://lists.fedoraproject.org/archives/list/[email protected]/message/DDHOAATPWJCXRNFMJ2SASDBBNU5RJONY/

https://lists.fedoraproject.org/archives/list/[email protected]/message/EXDDAOWSAIEFQNBHWYE6PPYFV4QXGMCD/

https://lists.fedoraproject.org/archives/list/[email protected]/message/XVEP3LAK4JSPRXFO4QF4GG2IVXADV3SO/

https://security.FreeBSD.org/advisories/FreeBSD-SA-20:11.openssl.asc

https://security.gentoo.org/glsa/202004-10

https://security.netapp.com/advisory/ntap-20200424-0003/

https://security.netapp.com/advisory/ntap-20200717-0004/

https://www.debian.org/security/2020/dsa-4661

https://www.openssl.org/news/secadv/20200421.txt

https://www.oracle.com/security-alerts/cpujul2020.html

https://www.oracle.com/security-alerts/cpuoct2020.html

https://www.synology.com/security/advisory/Synology_SA_20_05

https://www.synology.com/security/advisory/Synology_SA_20_05_OpenSSL

https://www.tenable.com/security/tns-2020-03

https://www.tenable.com/security/tns-2020-04

Details

Source: MITRE

Published: 2020-04-21

Updated: 2020-10-20

Type: CWE-476

Risk Information

CVSS v2.0

Base Score: 5

Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P

Impact Score: 2.9

Exploitability Score: 10

Severity: MEDIUM

CVSS v3.0

Base Score: 7.5

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Impact Score: 3.6

Exploitability Score: 3.9

Severity: HIGH