Описание
A vulnerability was found in OpenSSH when the VerifyHostKeyDNS option is enabled. A machine-in-the-middle attack can be performed by a malicious machine impersonating a legit server. This issue occurs due to how OpenSSH mishandles error codes in specific conditions when verifying the host key. For an attack to be considered successful, the attacker needs to manage to exhaust the client's memory resource first, turning the attack complexity high.
Отчет
This issue is rated as a moderate severity vulnerability instead of important because it requires specific conditions to be exploitable. First, the OpenSSH client must have the VerifyHostKeyDNS option enabled, which is disabled by default in Red Hat Enterprise Linux (RHEL). Additionally, while the attack allows a machine-in-the-middle (MITM) adversary to trick the client into accepting an incorrect host key, it does not directly lead to code execution or immediate system compromise. Instead, the attack requires additional steps, such as credential interception or session hijacking to fully exploit the breach.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | openssh | Not affected | ||
| Red Hat Enterprise Linux 6 | openssh | Out of support scope | ||
| Red Hat Enterprise Linux 7 | openssh | Out of support scope | ||
| Red Hat OpenShift Container Platform 4 | rhcos | Fix deferred | ||
| Red Hat Enterprise Linux 8 | openssh | Fixed | RHSA-2025:16823 | 26.09.2025 |
| Red Hat Enterprise Linux 8 | openssh | Fixed | RHSA-2025:16823 | 26.09.2025 |
| Red Hat Enterprise Linux 9 | openssh | Fixed | RHSA-2025:6993 | 13.05.2025 |
| Red Hat Enterprise Linux 9 | openssh | Fixed | RHSA-2025:6993 | 13.05.2025 |
| Red Hat Enterprise Linux 9.4 Extended Update Support | openssh | Fixed | RHSA-2025:3837 | 14.04.2025 |
| Red Hat Discovery 1.14 | discovery/discovery-server-rhel9 | Fixed | RHSA-2025:8385 | 02.06.2025 |
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Дополнительная информация
Статус:
6.8 Medium
CVSS3
Связанные уязвимости
A vulnerability was found in OpenSSH when the VerifyHostKeyDNS option is enabled. A machine-in-the-middle attack can be performed by a malicious machine impersonating a legit server. This issue occurs due to how OpenSSH mishandles error codes in specific conditions when verifying the host key. For an attack to be considered successful, the attacker needs to manage to exhaust the client's memory resource first, turning the attack complexity high.
A vulnerability was found in OpenSSH when the VerifyHostKeyDNS option is enabled. A machine-in-the-middle attack can be performed by a malicious machine impersonating a legit server. This issue occurs due to how OpenSSH mishandles error codes in specific conditions when verifying the host key. For an attack to be considered successful, the attacker needs to manage to exhaust the client's memory resource first, turning the attack complexity high.
Openssh: machine-in-the-middle attack if verifyhostkeydns is enabled
A vulnerability was found in OpenSSH when the VerifyHostKeyDNS option ...
6.8 Medium
CVSS3