Описание
When IMAP compression is enabled, the same compression state is reused across responses in a session, so response sizes depend on both attacker-supplied mail and other mail in the same mailbox. An attacker that can send mail to a user and can also observe the sizes of that user's IMAP traffic can confirm whether the body of a small message matches a guessed text. Recovery of arbitrary unknown content was not demonstrated, but the attack can disclose whether a secret-like message body matches a candidate. Disable IMAP compression. Update to non-vulnerable version. No publicly available exploits are known.
A flaw was found in dovecot where, when IMAP compression is enabled, the system reuses the same compression state across responses within a session. This allows a remote attacker, who can send mail to a user and monitor the sizes of their IMAP traffic, to potentially deduce the content of small messages. By observing response sizes, an attacker could confirm if a secret message body matches a guessed text, leading to information disclosure.
Меры по смягчению последствий
To mitigate this issue, disable IMAP compression in the Dovecot configuration. This typically involves setting imap_compression = no in the relevant Dovecot configuration file. After making this change, restart the Dovecot service for the mitigation to take effect. Restarting the service may temporarily interrupt IMAP access for users.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | dovecot | Fix deferred | ||
| Red Hat Enterprise Linux 6 | dovecot | Out of support scope | ||
| Red Hat Enterprise Linux 7 | dovecot | Fix deferred | ||
| Red Hat Enterprise Linux 8 | dovecot | Fix deferred | ||
| Red Hat Enterprise Linux 9 | dovecot | Fix deferred |
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Дополнительная информация
Статус:
EPSS
3.7 Low
CVSS3
Связанные уязвимости
When IMAP compression is enabled, the same compression state is reused across responses in a session, so response sizes depend on both attacker-supplied mail and other mail in the same mailbox. An attacker that can send mail to a user and can also observe the sizes of that user's IMAP traffic can confirm whether the body of a small message matches a guessed text. Recovery of arbitrary unknown content was not demonstrated, but the attack can disclose whether a secret-like message body matches a candidate. Disable IMAP compression. Update to non-vulnerable version. No publicly available exploits are known.
When IMAP compression is enabled, the same compression state is reused across responses in a session, so response sizes depend on both attacker-supplied mail and other mail in the same mailbox. An attacker that can send mail to a user and can also observe the sizes of that user's IMAP traffic can confirm whether the body of a small message matches a guessed text. Recovery of arbitrary unknown content was not demonstrated, but the attack can disclose whether a secret-like message body matches a candidate. Disable IMAP compression. Update to non-vulnerable version. No publicly available exploits are known.
When IMAP compression is enabled, the same compression state is reused ...
When IMAP compression is enabled, the same compression state is reused across responses in a session, so response sizes depend on both attacker-supplied mail and other mail in the same mailbox. An attacker that can send mail to a user and can also observe the sizes of that user's IMAP traffic can confirm whether the body of a small message matches a guessed text. Recovery of arbitrary unknown content was not demonstrated, but the attack can disclose whether a secret-like message body matches a candidate. Disable IMAP compression. Update to non-vulnerable version. No publicly available exploits are known.
EPSS
3.7 Low
CVSS3