Описание
Issue Summary: Cryptographic Message Services (CMS) processing fails to perform
sufficient input validation on the cipher and tag length fields of
AuthEnvelopedData containers, leading to various potential compromises.
Impact Summary: Attackers making use of these vulnerabilities may achieve
key-equivalent functionality for a given CMS recipient and/or bypass integrity
validation for a given message.
In one use case, an attacker may send a CMS message containing
AuthEnvelopedData with the cipher specified as a non-AEAD cipher. OpenSSL
erroneously allows this selection, and attempts to decrypt and validate the
message.
An on-path attacker who captures one legitimate AES-GCM AuthEnvelopedData
addressed to the victim can re-emit it with the recipientInfos set left
byte-for-byte intact, so the victim's private key still unwraps the genuine CEK
(the content-encryption key), but with the inner OID rewritten to AES-256-OFB
(Output Feedback Mode, an unauthenticated keystream mode) and with an
attacker-chosen IV and ciphertext. The victim initializes AES-256-OFB under the
real CEK, never consults the MAC field, and CMS_decrypt() returns success.
If the application under attack responds to the attacker with any indicator
showing success or failure of the decryption effort, it is possible for the
attacker to use this as an oracle to obtain key equivalent functionality for the
CEK used for the chosen recipient of the message.
In another use case, an attacker can reduce the tag length of the chosen AEAD
cipher for a given AuthEnvelopedData container to be a single byte long,
allowing an attacker to brute force CMS decryption, producing an integrity
bypass for applications that trust CMS_decrypt() to reject modified content.
The FIPS modules are not affected by this issue.
A flaw was found in OpenSSL's Cryptographic Message Services (CMS) AuthEnvelopedData processing. An on-path attacker can exploit insufficient input validation on cipher and tag length fields by sending specially crafted CMS messages. This can lead to the forging of messages or bypassing integrity validation. Consequently, an attacker may achieve key-equivalent functionality for a given CMS recipient.
Отчет
Moderate: This flaw in OpenSSL's Cryptographic Message Services (CMS) AuthEnvelopedData processing could allow an on-path attacker to forge messages or bypass integrity validation. This is due to insufficient input validation on cipher and tag length fields, potentially leading to key-equivalent functionality or integrity bypass in applications utilizing affected OpenSSL versions for CMS AuthEnvelopedData.
Меры по смягчению последствий
Systems configured to operate in FIPS mode are not affected by this vulnerability. To mitigate this issue, ensure that OpenSSL is operating in FIPS mode by enabling the system-wide FIPS policy. This may have broader implications for cryptographic operations on the system and should be evaluated for compatibility with existing applications. A system reboot may be required for the changes to take effect.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | edk2 | Not affected | ||
| Red Hat Enterprise Linux 10 | shim | Not affected | ||
| Red Hat Enterprise Linux 10 | shim-unsigned-aarch64 | Not affected | ||
| Red Hat Enterprise Linux 10 | shim-unsigned-x64 | Not affected | ||
| Red Hat Enterprise Linux 6 | openssl | Not affected | ||
| Red Hat Enterprise Linux 7 | ovmf | Not affected | ||
| Red Hat Enterprise Linux 8 | compat-openssl10 | Not affected | ||
| Red Hat Enterprise Linux 8 | edk2 | Not affected | ||
| Red Hat Enterprise Linux 8 | mingw-openssl | Not affected | ||
| Red Hat Enterprise Linux 8 | openssl | Affected |
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Дополнительная информация
Статус:
EPSS
7.4 High
CVSS3
Связанные уязвимости
Issue Summary: Cryptographic Message Services (CMS) processing fails to perform sufficient input validation on the cipher and tag length fields of AuthEnvelopedData containers, leading to various potential compromises. Impact Summary: Attackers making use of these vulnerabilities may achieve key-equivalent functionality for a given CMS recipient and/or bypass integrity validation for a given message. In one use case, an attacker may send a CMS message containing AuthEnvelopedData with the cipher specified as a non-AEAD cipher. OpenSSL erroneously allows this selection, and attempts to decrypt and validate the message. An on-path attacker who captures one legitimate AES-GCM AuthEnvelopedData addressed to the victim can re-emit it with the recipientInfos set left byte-for-byte intact, so the victim's private key still unwraps the genuine CEK (the content-encryption key), but with the inner OID rewritten to AES-256-OFB (Output Feedback Mode, an unauthenticated keystream mode) and with...
Issue Summary: Cryptographic Message Services (CMS) processing fails to perform sufficient input validation on the cipher and tag length fields of AuthEnvelopedData containers, leading to various potential compromises. Impact Summary: Attackers making use of these vulnerabilities may achieve key-equivalent functionality for a given CMS recipient and/or bypass integrity validation for a given message. In one use case, an attacker may send a CMS message containing AuthEnvelopedData with the cipher specified as a non-AEAD cipher. OpenSSL erroneously allows this selection, and attempts to decrypt and validate the message. An on-path attacker who captures one legitimate AES-GCM AuthEnvelopedData addressed to the victim can re-emit it with the recipientInfos set left byte-for-byte intact, so the victim's private key still unwraps the genuine CEK (the content-encryption key), but with the inner OID rewritten to AES-256-OFB (Output Feedback Mode, an unauthenticated keystream mode) and with
CMS AuthEnvelopedData Processing May Accept Forged Messages
Issue Summary: Cryptographic Message Services (CMS) processing fails t ...
Issue Summary: Cryptographic Message Services (CMS) processing fails to perform sufficient input validation on the cipher and tag length fields of AuthEnvelopedData containers, leading to various potential compromises. Impact Summary: Attackers making use of these vulnerabilities may achieve key-equivalent functionality for a given CMS recipient and/or bypass integrity validation for a given message. In one use case, an attacker may send a CMS message containing AuthEnvelopedData with the cipher specified as a non-AEAD cipher. OpenSSL erroneously allows this selection, and attempts to decrypt and validate the message. An on-path attacker who captures one legitimate AES-GCM AuthEnvelopedData addressed to the victim can re-emit it with the recipientInfos set left byte-for-byte intact, so the victim's private key still unwraps the genuine CEK (the content-encryption key), but with the inner OID rewritten to AES-256-OFB (Output Feedback Mode, an unauthenticated keystream mode) and w...
EPSS
7.4 High
CVSS3