Описание
Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid.
OCSP response verification in pubkey_ocsp:verify_response/5 and pubkey_ocsp:is_authorized_responder/3 in lib/public_key/src/pubkey_ocsp.erl does not check the validity period (notBefore/notAfter) of the OCSP responder certificate. An attacker who has obtained the private key of an expired CA-designated OCSP responder certificate can forge OCSP responses that Erlang/OTP accepts as valid.
This affects TLS clients using OCSP stapling via the ssl application: a malicious or compromised server can present a revoked TLS certificate together with a forged OCSP response signed by an expired responder key, and the client will accept the revoked certificate as valid. It also affects applications calling public_key:pkix_ocsp_validate/5 directly, where the impact depends on the use case — server-side client certificate validation using this API may allow authentication bypass with a revoked client certificate.
This issue affects OTP from OTP 27.0 before OTP 29.0.1, OTP 28.5.0.1 and OTP 27.3.4.12, corresponding to public_key from 1.16 before 1.21.1, 1.20.3.1 and 1.17.1.3.
A flaw was found in Erlang OTP's public_key application, specifically in the Online Certificate Status Protocol (OCSP) response verification. A remote attacker who has obtained the private key of an expired Certificate Authority (CA)-designated OCSP responder certificate can forge OCSP responses. This allows a malicious server to present a revoked Transport Layer Security (TLS) certificate, which a client would then accept as valid, leading to an authentication bypass. This vulnerability can also affect applications directly using the public_key:pkix_ocsp_validate/5 API, potentially enabling authentication bypass with revoked client certificates.
Отчет
Red Hat rates this flaw as Low rather than Important because exploitation requires the attacker to possess the private key of an expired CA-designated OCSP responder certificate, and the affected OCSP stapling feature is not enabled by default in the Erlang ssl application. The direct impact is limited to integrity — a forged OCSP response is accepted, allowing a revoked certificate to appear valid.
Меры по смягчению последствий
For TLS clients using the Erlang ssl application, disable OCSP stapling by setting {stapling, no_staple} in the client options, or switch to CRL-based revocation checking with {crl_check, true}. For applications calling public_key:pkix_ocsp_validate/5 directly, validate the responder certificate's validity period in application code before calling the function.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat OpenStack Platform 16.2 | erlang | Not affected | ||
| Red Hat OpenStack Platform 17.1 | erlang | Not affected | ||
| Red Hat OpenStack Platform 18.0 | erlang | Not affected |
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Дополнительная информация
Статус:
EPSS
5.9 Medium
CVSS3
Связанные уязвимости
Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid. OCSP response verification in pubkey_ocsp:verify_response/5 and pubkey_ocsp:is_authorized_responder/3 in lib/public_key/src/pubkey_ocsp.erl does not check the validity period (notBefore/notAfter) of the OCSP responder certificate. An attacker who has obtained the private key of an expired CA-designated OCSP responder certificate can forge OCSP responses that Erlang/OTP accepts as valid. This affects TLS clients using OCSP stapling via the ssl application: a malicious or compromised server can present a revoked TLS certificate together with a forged OCSP response signed by an expired responder key, and the client will accept the revoked certificate as valid. It also affects applications calling public_key:pkix_ocsp_validate/5 directly, where the impact depends on the use case — server-side clie...
Improper Certificate Validation vulnerability in Erlang OTP public_key (pubkey_ocsp module) allows forged OCSP responses signed with an expired responder certificate to be accepted as valid. OCSP response verification in pubkey_ocsp:verify_response/5 and pubkey_ocsp:is_authorized_responder/3 in lib/public_key/src/pubkey_ocsp.erl does not check the validity period (notBefore/notAfter) of the OCSP responder certificate. An attacker who has obtained the private key of an expired CA-designated OCSP responder certificate can forge OCSP responses that Erlang/OTP accepts as valid. This affects TLS clients using OCSP stapling via the ssl application: a malicious or compromised server can present a revoked TLS certificate together with a forged OCSP response signed by an expired responder key, and the client will accept the revoked certificate as valid. It also affects applications calling public_key:pkix_ocsp_validate/5 directly, where the impact depends on the use case — server-side clien
Improper Certificate Validation vulnerability in Erlang OTP public_key ...
EPSS
5.9 Medium
CVSS3