Описание
Sigstore Timestamp Authority is a service for issuing RFC 3161 timestamps. Versions 2.0.5 and below contain an authorization bypass vulnerability in the VerifyTimestampResponse function. VerifyTimestampResponse correctly verifies the certificate chain signature, but the TSA-specific constraint checks in VerifyLeafCert uses the first non-CA certificate from the PKCS#7 certificate bag instead of the leaf certificate from the verified chain. An attacker can exploit this by prepending a forged certificate to the certificate bag while the message is signed with an authorized key, causing the library to validate the signature against one certificate but perform authorization checks against another. This vulnerability only affects users of the timestamp-authority/v2/pkg/verification package and does not affect the timestamp-authority service itself or sigstore-go. The issue has been fixed in version 2.0.6.
A flaw was found in timestamp-authority, specifically in the timestamp-authority/v2/pkg/verification package. An attacker can exploit this issue by prepending a forged certificate to the certificate bag while the message is signed with an authorized key. This causes the library to validate the signature against one certificate but perform authorization checks against another, leading to an authorization bypass.
Отчет
This vulnerability allows an attacker to bypass authorization checks by prepending a forged certificate to the certificate bag. The library validates the signature against one certificate while performing authorization checks against another.
Additionally, a user or an automated system must actively run the VerifyTimestampResponse function against the attacker-supplied payload. Due to this reason, this flaw has been rated with a moderate severity.
This issue only impacts users of the timestamp-authority/v2/pkg/verification package and does not affect the timestamp-authority service or sigstore-go.
Меры по смягчению последствий
To mitigate this vulnerability, users of VerifyTimestampResponse can use the TSACertificate option to explicitly specify the exact certificate they expect to be used.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Advanced Cluster Security 4 | advanced-cluster-security/rhacs-main-rhel8 | Fix deferred | ||
| Red Hat Advanced Cluster Security 4 | advanced-cluster-security/rhacs-rhel8-operator | Fix deferred | ||
| Red Hat Advanced Cluster Security 4 | advanced-cluster-security/rhacs-roxctl-rhel8 | Fix deferred | ||
| Red Hat Advanced Cluster Security 4 | advanced-cluster-security/rhacs-scanner-v4-rhel8 | Fix deferred | ||
| Red Hat Trusted Artifact Signer | rhtas/cosign-rhel9 | Fix deferred | ||
| Red Hat Trusted Artifact Signer | rhtas/ec-rhel9 | Fix deferred | ||
| Red Hat Trusted Artifact Signer | rhtas/gitsign-rhel9 | Fix deferred | ||
| Security Profiles Operator | compliance/openshift-security-profiles-operator-bundle | Fix deferred | ||
| Security Profiles Operator | compliance/openshift-security-profiles-rhel8-operator | Fix deferred |
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Дополнительная информация
Статус:
EPSS
5.5 Medium
CVSS3
Связанные уязвимости
Sigstore Timestamp Authority is a service for issuing RFC 3161 timestamps. Versions 2.0.5 and below contain an authorization bypass vulnerability in the VerifyTimestampResponse function. VerifyTimestampResponse correctly verifies the certificate chain signature, but the TSA-specific constraint checks in VerifyLeafCert uses the first non-CA certificate from the PKCS#7 certificate bag instead of the leaf certificate from the verified chain. An attacker can exploit this by prepending a forged certificate to the certificate bag while the message is signed with an authorized key, causing the library to validate the signature against one certificate but perform authorization checks against another. This vulnerability only affects users of the timestamp-authority/v2/pkg/verification package and does not affect the timestamp-authority service itself or sigstore-go. The issue has been fixed in version 2.0.6.
Sigstore Timestamp Authority is a service for issuing RFC 3161 timestamps. Versions 2.0.5 and below contain an authorization bypass vulnerability in the VerifyTimestampResponse function. VerifyTimestampResponse correctly verifies the certificate chain signature, but the TSA-specific constraint checks in VerifyLeafCert uses the first non-CA certificate from the PKCS#7 certificate bag instead of the leaf certificate from the verified chain. An attacker can exploit this by prepending a forged certificate to the certificate bag while the message is signed with an authorized key, causing the library to validate the signature against one certificate but perform authorization checks against another. This vulnerability only affects users of the timestamp-authority/v2/pkg/verification package and does not affect the timestamp-authority service itself or sigstore-go. The issue has been fixed in version 2.0.6.
Sigstore Timestamp Authority is a service for issuing RFC 3161 timesta ...
Sigstore Timestamp Authority has Improper Certificate Validation in verifier
EPSS
5.5 Medium
CVSS3