Описание
A flaw was found in the admin backend of gvfs. The privileged gvfsd-admin daemon changes the ownership of newly created private D-Bus sockets by calling the link-following chown() function on a pathname inside a user-controlled directory. A local attacker can exploit this via a Time-of-Check Time-of-Use (TOCTOU) race condition and exchange the socket pathname with a symbolic link pointing to an arbitrary root-owned file (such as /etc/pam.d/su). The daemon subsequently follows the symlink and changes the ownership of the targeted root-owned file to the attacker's user ID. This allows an authenticated local attacker to modify critical system files, leading to a full local privilege escalation to root.
Отчет
To exploit this issue, an attacker needs local access to the system and the ability to start the gvfsd-admin daemon. Furthermore, the attacker must successfully win a timing race condition, increasing the attack complexity. However, successful exploitation can allow the attacker to change the ownership of arbitrary system files, resulting in a full local privilege escalation to root. For these reasons, this vulnerability has been rated with a high severity.
Меры по смягчению последствий
To mitigate this issue, adjust Polkit rules to require password authentication to start gvfsd-admin or remove execute permissions of the gvfsd-admin binary to prevent execution.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | gvfs | Affected | ||
| Red Hat Enterprise Linux 6 | gvfs | Affected | ||
| Red Hat Enterprise Linux 7 | gvfs | Affected | ||
| Red Hat Enterprise Linux 8 | gvfs | Affected | ||
| Red Hat Enterprise Linux 9 | gvfs | Affected |
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Дополнительная информация
Статус:
7 High
CVSS3
Связанные уязвимости
(A flaw was found in the admin backend of gvfs. The privileged gvfsd-ad ...)
A flaw was found in the admin backend of gvfs. The privileged gvfsd-admin daemon changes the ownership of newly created private D-Bus sockets by calling the link-following chown() function on a pathname inside a user-controlled directory. A local attacker can exploit this via a Time-of-Check Time-of-Use (TOCTOU) race condition and exchange the socket pathname with a symbolic link pointing to an arbitrary root-owned file (such as /etc/pam.d/su). The daemon subsequently follows the symlink and changes the ownership of the targeted root-owned file to the attacker's user ID. This allows an authenticated local attacker to modify critical system files, leading to a full local privilege escalation to root.
A flaw was found in the admin backend of gvfs. The privileged gvfsd-ad ...
A flaw was found in the admin backend of gvfs. The privileged gvfsd-admin daemon changes the ownership of newly created private D-Bus sockets by calling the link-following chown() function on a pathname inside a user-controlled directory. A local attacker can exploit this via a Time-of-Check Time-of-Use (TOCTOU) race condition and exchange the socket pathname with a symbolic link pointing to an arbitrary root-owned file (such as /etc/pam.d/su). The daemon subsequently follows the symlink and changes the ownership of the targeted root-owned file to the attacker's user ID. This allows an authenticated local attacker to modify critical system files, leading to a full local privilege escalation to root.
7 High
CVSS3