Описание
In Sudo before 1.8.26, if pwfeedback is enabled in /etc/sudoers, users can trigger a stack-based buffer overflow in the privileged sudo process. (pwfeedback is a default setting in Linux Mint and elementary OS; however, it is NOT the default for upstream and many other packages, and would exist only if enabled by an administrator.) The attacker needs to deliver a long string to the stdin of getln() in tgetpass.c.
A flaw was found in the Sudo application when the ’pwfeedback' option is set to true on the sudoers file. An authenticated user can use this vulnerability to trigger a stack-based buffer overflow under certain conditions even without Sudo privileges. The buffer overflow may allow an attacker to expose or corrupt memory information, crash the Sudo application, or possibly inject code to be run as a root user.
Отчет
This flaw can only be exploited if the option pwfeedback is enabled in sudo configuration. This option is not enabled by default in any version of Red Hat Enterprise Linux.
The sudo packages distributed with Red Hat Enterprise Linux versions are compiled using gcc's stack-protector feature. The "Stack Smashing Protection" may help mitigate code execution attacks for this flaw.
Red Hat Enterprise Linux 5 is not affected as it doesn't include the commit which introduced the vulnerability.
Меры по смягчению последствий
Please follow the steps bellow as mitigation:
- Check the default properties set for sudo by running:
- If
pwfeedbackis enabled as shown above, edit your/etc/sudoersfile, changing the line:
To:
This will disable visual feedback on password typing, making sure the attack is not possible anymore.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 5 | sudo | Not affected | ||
| Red Hat Enterprise Linux 6 | sudo | Fixed | RHSA-2020:0726 | 05.03.2020 |
| Red Hat Enterprise Linux 7 | sudo | Fixed | RHSA-2020:0540 | 19.02.2020 |
| Red Hat Enterprise Linux 8 | sudo | Fixed | RHSA-2020:0487 | 14.02.2020 |
| Red Hat Enterprise Linux 8.0 Update Services for SAP Solutions | sudo | Fixed | RHSA-2020:0509 | 14.02.2020 |
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Дополнительная информация
Статус:
EPSS
7.8 High
CVSS3
Связанные уязвимости
In Sudo before 1.8.26, if pwfeedback is enabled in /etc/sudoers, users can trigger a stack-based buffer overflow in the privileged sudo process. (pwfeedback is a default setting in Linux Mint and elementary OS; however, it is NOT the default for upstream and many other packages, and would exist only if enabled by an administrator.) The attacker needs to deliver a long string to the stdin of getln() in tgetpass.c.
In Sudo before 1.8.26, if pwfeedback is enabled in /etc/sudoers, users can trigger a stack-based buffer overflow in the privileged sudo process. (pwfeedback is a default setting in Linux Mint and elementary OS; however, it is NOT the default for upstream and many other packages, and would exist only if enabled by an administrator.) The attacker needs to deliver a long string to the stdin of getln() in tgetpass.c.
In Sudo before 1.8.26, if pwfeedback is enabled in /etc/sudoers, users ...
EPSS
7.8 High
CVSS3