Описание
Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes. This allows a remote peer to fragment TCP resend queues significantly more than if a larger MSS were enforced. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commits 967c05aee439e6e5d7d805e195b3a20ef5c433d6 and 5f3e2bf008c2221478101ee72f5cb4654b9fc363.
An excessive resource consumption flaw was found in the way the Linux kernel's networking subsystem processed TCP segments. If the Maximum Segment Size (MSS) of a TCP connection was set to low values, such as 48 bytes, it can leave as little as 8 bytes for the user data, which significantly increases the Linux kernel's resource (CPU, Memory, and Bandwidth) utilization. A remote attacker could use this flaw to cause a denial of service (DoS) by repeatedly sending network traffic on a TCP connection with low TCP MSS.
Отчет
Red Hat Product Security is aware of this issue. Updates will be released as they become available. For additional information, please refer to the Red Hat Knowledgebase article: https://access.redhat.com/security/vulnerabilities/tcpsack Red Hat Enterprise Linux 5 is now in the Extended Life Phase of maintenance life cycle. This has been rated as having Moderate security impact and is not currently planned to be addressed in future updates. For additional information, refer to the Red Hat Enterprise Linux Life Cycle: https://access.redhat.com/support/policy/updates/errata/.
Меры по смягчению последствий
For mitigation, please refer to the Red Hat Knowledgebase article: https://access.redhat.com/security/vulnerabilities/tcpsack
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 5 | kernel | Out of support scope | ||
| Red Hat Enterprise Linux 6 | kernel | Fixed | RHSA-2019:1488 | 17.06.2019 |
| Red Hat Enterprise Linux 6.5 Advanced Update Support | kernel | Fixed | RHSA-2019:1490 | 17.06.2019 |
| Red Hat Enterprise Linux 6.6 Advanced Update Support | kernel | Fixed | RHSA-2019:1489 | 17.06.2019 |
| Red Hat Enterprise Linux 7 | kernel-rt | Fixed | RHSA-2019:1486 | 17.06.2019 |
| Red Hat Enterprise Linux 7 | kernel | Fixed | RHSA-2019:1481 | 17.06.2019 |
| Red Hat Enterprise Linux 7 | kernel-alt | Fixed | RHSA-2019:1602 | 25.06.2019 |
| Red Hat Enterprise Linux 7.2 Advanced Update Support | kernel | Fixed | RHSA-2019:1485 | 17.06.2019 |
| Red Hat Enterprise Linux 7.2 Telco Extended Update Support | kernel | Fixed | RHSA-2019:1485 | 17.06.2019 |
| Red Hat Enterprise Linux 7.2 Update Services for SAP Solutions | kernel | Fixed | RHSA-2019:1485 | 17.06.2019 |
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Дополнительная информация
Статус:
EPSS
5.3 Medium
CVSS3
Связанные уязвимости
Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes. This allows a remote peer to fragment TCP resend queues significantly more than if a larger MSS were enforced. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commits 967c05aee439e6e5d7d805e195b3a20ef5c433d6 and 5f3e2bf008c2221478101ee72f5cb4654b9fc363.
Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes. This allows a remote peer to fragment TCP resend queues significantly more than if a larger MSS were enforced. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commits 967c05aee439e6e5d7d805e195b3a20ef5c433d6 and 5f3e2bf008c2221478101ee72f5cb4654b9fc363.
Jonathan Looney discovered that the Linux kernel default MSS is hard-c ...
Jonathan Looney discovered that the Linux kernel default MSS is hard-coded to 48 bytes. This allows a remote peer to fragment TCP resend queues significantly more than if a larger MSS were enforced. A remote attacker could use this to cause a denial of service. This has been fixed in stable kernel releases 4.4.182, 4.9.182, 4.14.127, 4.19.52, 5.1.11, and is fixed in commits 967c05aee439e6e5d7d805e195b3a20ef5c433d6 and 5f3e2bf008c2221478101ee72f5cb4654b9fc363.
Уязвимость ядра операционной системы Linux, вызванная ошибками при обработке сегментов минимального размера, позволяющая нарушителю вызвать отказ в обслуживании
EPSS
5.3 Medium
CVSS3