CVE-2020-1971 Detail

Current Description

The X.509 GeneralName type is a generic type for representing different types of names. One of those name types is known as EDIPartyName. OpenSSL provides a function GENERAL_NAME_cmp which compares different instances of a GENERAL_NAME to see if they are equal or not. This function behaves incorrectly when both GENERAL_NAMEs contain an EDIPARTYNAME. A NULL pointer dereference and a crash may occur leading to a possible denial of service attack. OpenSSL itself uses the GENERAL_NAME_cmp function for two purposes: 1) Comparing CRL distribution point names between an available CRL and a CRL distribution point embedded in an X509 certificate 2) When verifying that a timestamp response token signer matches the timestamp authority name (exposed via the API functions TS_RESP_verify_response and TS_RESP_verify_token) If an attacker can control both items being compared then that attacker could trigger a crash. For example if the attacker can trick a client or server into checking a malicious certificate against a malicious CRL then this may occur. Note that some applications automatically download CRLs based on a URL embedded in a certificate. This checking happens prior to the signatures on the certificate and CRL being verified. OpenSSL's s_server, s_client and verify tools have support for the "-crl_download" option which implements automatic CRL downloading and this attack has been demonstrated to work against those tools. Note that an unrelated bug means that affected versions of OpenSSL cannot parse or construct correct encodings of EDIPARTYNAME. However it is possible to construct a malformed EDIPARTYNAME that OpenSSL's parser will accept and hence trigger this attack. All OpenSSL 1.1.1 and 1.0.2 versions are affected by this issue. Other OpenSSL releases are out of support and have not been checked. Fixed in OpenSSL 1.1.1i (Affected 1.1.1-1.1.1h). Fixed in OpenSSL 1.0.2x (Affected 1.0.2-1.0.2w).


View Analysis Description

Severity



CVSS 3.x Severity and Metrics:

NIST CVSS score
NIST: NVD
Base Score:  5.9 MEDIUM
Vector:  CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H


NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have published a CVSS score for this CVE based on publicly available information at the time of analysis. The CNA has not provided a score within the CVE List.

References to Advisories, Solutions, and Tools

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Hyperlink Resource
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=2154ab83e14ede338d2ede9bbe5cdfce5d5a6c9e Broken Link 
https://git.openssl.org/gitweb/?p=openssl.git;a=commitdiff;h=f960d81215ebf3f65e03d4d5d857fb9b666d6920 Patch  Vendor Advisory 
https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA44676 Third Party Advisory 
https://lists.apache.org/thread.html/r63c6f2dd363d9b514d0a4bcf624580616a679898cc14c109a49b750c@%3Cdev.tomcat.apache.org%3E Mailing List  Third Party Advisory 
https://lists.apache.org/thread.html/rbb769f771711fb274e0a4acb1b5911c8aab544a6ac5e8c12d40c5143@%3Ccommits.pulsar.apache.org%3E Third Party Advisory 
https://lists.debian.org/debian-lts-announce/2020/12/msg00020.html Mailing List  Third Party Advisory 
https://lists.debian.org/debian-lts-announce/2020/12/msg00021.html Mailing List  Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DGSI34Y5LQ5RYXN4M2I5ZQT65LFVDOUU/ Third Party Advisory 
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PWPSSZNZOBJU2YR6Z4TGHXKYW3YP5QG7/ Third Party Advisory 
https://security.FreeBSD.org/advisories/FreeBSD-SA-20:33.openssl.asc Third Party Advisory 
https://security.gentoo.org/glsa/202012-13 Third Party Advisory 
https://security.netapp.com/advisory/ntap-20201218-0005/ Third Party Advisory 
https://security.netapp.com/advisory/ntap-20210513-0002/
https://www.debian.org/security/2020/dsa-4807 Third Party Advisory 
https://www.openssl.org/news/secadv/20201208.txt Vendor Advisory 
https://www.oracle.com//security-alerts/cpujul2021.html
https://www.oracle.com/security-alerts/cpuApr2021.html
https://www.oracle.com/security-alerts/cpujan2021.html Third Party Advisory 
https://www.tenable.com/security/tns-2020-11 Third Party Advisory 
https://www.tenable.com/security/tns-2021-09
https://www.tenable.com/security/tns-2021-10

Weakness Enumeration

CWE-ID CWE Name Source
CWE-476 NULL Pointer Dereference cwe source acceptance level NIST  

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Change History

20 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2020-1971
NVD Published Date:
12/08/2020
NVD Last Modified:
07/20/2021
Source:
OpenSSL Software Foundation