RUSTSEC-2021-0056

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Source

https://rustsec.org/advisories/RUSTSEC-2021-0056

Import Source

https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2021-0056.json

JSON Data

https://api.osv.dev/v1/vulns/RUSTSEC-2021-0056

Aliases

Published

2021-05-01T12:00:00Z

Modified

2023-12-06T00:46:15.901591Z

Severity

7.4 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N CVSS Calculator

Summary

CA certificate check bypass with X509_V_FLAG_X509_STRICT

Details

The X509VFLAGX509STRICT 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 X509VFLAGX509STRICT 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.

References

Affected packages

crates.io / openssl-src

Package

Name: openssl-src; View open source insights on deps.dev
Purl: pkg:cargo/openssl-src

Affected ranges

Type: SEMVER
Events: Introduced

111.11.0

Fixed

111.15.0

Ecosystem specific

{
    "affected_functions": null,
    "affects": {
        "os": [],
        "functions": [],
        "arch": []
    }
}

Database specific

{
    "cvss": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N",
    "informational": null,
    "categories": [
        "crypto-failure"
    ]
}