Описание
Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG key used by the server. Since BIND, by default, configures a local session key even on servers whose configuration does not otherwise make use of it, almost all current BIND servers are vulnerable. In releases of BIND dating from March 2018 and after, an assertion check in tsig.c detects this inconsistent state and deliberately exits. Prior to the introduction of the check the server would continue operating in an inconsistent state, with potentially harmful results.
An assertion failure was found in BIND, which checks the validity of messages containing TSIG resource records. This flaw allows an attacker that knows or successfully guesses the name of the TSIG key used by the server to use a specially-crafted message, potentially causing a BIND server to reach an inconsistent state or cause a denial of service. A majority of BIND servers have an internally-generated TSIG session key whose name is trivially guessable, and that key exposes the vulnerability unless specifically disabled.
Отчет
Upstream has released additional information about this flaw. Details available at: https://kb.isc.org/docs/cve-2020-8617-faq-and-supplemental-information
Меры по смягчению последствий
BIND servers have an internally-generated TSIG session key whose name is trivially guessable, and that key exposes the vulnerability unless specifically disabled. Upstream recommends using random value in session-keyname as a workaround. This can be added to named.conf configuration file.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 5 | bind | Out of support scope | ||
| Red Hat Enterprise Linux 5 | bind97 | Out of support scope | ||
| Red Hat Enterprise Linux 6 | bind | Fixed | RHSA-2020:2383 | 03.06.2020 |
| Red Hat Enterprise Linux 6.5 Advanced Update Support | bind | Fixed | RHSA-2020:3379 | 10.08.2020 |
| Red Hat Enterprise Linux 6.6 Advanced Update Support | bind | Fixed | RHSA-2020:3378 | 10.08.2020 |
| Red Hat Enterprise Linux 7 | bind | Fixed | RHSA-2020:2344 | 01.06.2020 |
| Red Hat Enterprise Linux 7.2 Advanced Update Support | bind | Fixed | RHSA-2020:3471 | 18.08.2020 |
| Red Hat Enterprise Linux 7.3 Advanced Update Support | bind | Fixed | RHSA-2020:3470 | 18.08.2020 |
| Red Hat Enterprise Linux 7.3 Telco Extended Update Support | bind | Fixed | RHSA-2020:3470 | 18.08.2020 |
| Red Hat Enterprise Linux 7.3 Update Services for SAP Solutions | bind | Fixed | RHSA-2020:3470 | 18.08.2020 |
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Дополнительная информация
Статус:
7.5 High
CVSS3
Связанные уязвимости
Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG key used by the server. Since BIND, by default, configures a local session key even on servers whose configuration does not otherwise make use of it, almost all current BIND servers are vulnerable. In releases of BIND dating from March 2018 and after, an assertion check in tsig.c detects this inconsistent state and deliberately exits. Prior to the introduction of the check the server would continue operating in an inconsistent state, with potentially harmful results.
Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG key used by the server. Since BIND, by default, configures a local session key even on servers whose configuration does not otherwise make use of it, almost all current BIND servers are vulnerable. In releases of BIND dating from March 2018 and after, an assertion check in tsig.c detects this inconsistent state and deliberately exits. Prior to the introduction of the check the server would continue operating in an inconsistent state, with potentially harmful results.
Using a specially-crafted message, an attacker may potentially cause a ...
Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG key used by the server. Since BIND, by default, configures a local session key even on servers whose configuration does not otherwise make use of it, almost all current BIND servers are vulnerable. In releases of BIND dating from March 2018 and after, an assertion check in tsig.c detects this inconsistent state and deliberately exits. Prior to the introduction of the check the server would continue operating in an inconsistent state, with potentially harmful results.
Уязвимость компонента tsig.c DNS-сервера BIND, позволяющая нарушителю вызвать отказ в обслуживании
7.5 High
CVSS3