SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-3450

Starting from OpenSSL version 1.1.1h a check to disallow certificates in the chain that have explicitly encoded elliptic curve parameters was added as an additional strict check.

HIGH 7.4EPSS 18.3%

Does this matter?

EPSS puts the probability of exploitation in the next 30 days at 18.3%, higher than 97% of all known CVEs. Patch or mitigate before the next change window.

Description

The X509_V_FLAG_X509_STRICT flag enables additional security checks of the certificates present in a certificate chain. It is not set by default. Starting from OpenSSL version 1.1.1h a check to disallow certificates in the chain that have explicitly encoded elliptic curve parameters was added as an additional strict check. An error in the implementation of this check meant that the result of a previous check to confirm that certificates in the chain are valid CA certificates was overwritten. This effectively bypasses the check that non-CA certificates must not be able to issue other certificates. If a "purpose" has been configured then there is a subsequent opportunity for checks that the certificate is a valid CA. All of the named "purpose" values implemented in libcrypto perform this check. Therefore, where a purpose is set the certificate chain will still be rejected even when the strict flag has been used. A purpose is set by default in libssl client and server certificate verification routines, but it can be overridden or removed by an application. In order to be affected, an application must explicitly set the X509_V_FLAG_X509_STRICT verification flag and either not set a purpose for the certificate verification or, in the case of TLS client or server applications, override the default purpose. OpenSSL versions 1.1.1h and newer are affected by this issue. Users of these versions should upgrade to OpenSSL 1.1.1k. OpenSSL 1.0.2 is not impacted by this issue. Fixed in OpenSSL 1.1.1k (Affected 1.1.1h-1.1.1j).

CVSS 3.1
7.4 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS
18.34% probability · 97th percentile
CISA KEV
Not listed
Weakness
CWE-295
Affected
openssl/openssl · freebsd/freebsd · netapp/santricity smi-s provider firmware · netapp/storagegrid firmware · windriver/linux · netapp/cloud volumes ontap mediator · netapp/oncommand workflow automation · netapp/ontap select deploy administration utility · netapp/storagegrid · fedoraproject/fedora · tenable/nessus · tenable/nessus agent · tenable/nessus network monitor · oracle/commerce guided search · oracle/enterprise manager for storage management · oracle/graalvm · oracle/jd edwards enterpriseone tools · oracle/jd edwards world security · oracle/mysql connectors · oracle/mysql enterprise monitor · +13 more
Source
openssl-security@openssl.org

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.