RUSTSEC-2021-0056

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
2023-12-06T01:01:17.477139Z
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.

Database specific
{
    "license": "CC0-1.0"
}
References

Affected packages

crates.io / openssl-src

Package

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"
    ]
}