Описание
Incomplete blacklist vulnerability in the chfn function in libuser before 0.56.13-8 and 0.60 before 0.60-7, as used in the userhelper program in the usermode package, allows local users to cause a denial of service (/etc/passwd corruption) via a newline character in the GECOS field.
It was found that libuser, as used by the chfn userhelper functionality, did not properly filter out newline characters in GECOS fields. A local, authenticated user could use this flaw to corrupt the /etc/passwd file, resulting in a denial-of-service on the system.
Отчет
Red Hat Enterprise Linux 5 is now in Production 3 Phase of the support and maintenance life cycle. This vulnerability 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
Add pam_warn and pam_deny rules to /etc/pam.d/chfn and /etc/pam.d/chsh to prevent non-root users from using this functionality. With these edits, the files should contain: #%PAM-1.0 auth sufficient pam_rootok.so auth required pam_warn.so auth required pam_deny.so auth include system-auth account include system-auth password include system-auth session include system-auth Afterwards, attempts by unprivileged users to use chfn and chsh (and the respective functionality in the userhelper program) will fail, and will be logged (by default in /var/log/secure).
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 5 | libuser | Will not fix | ||
| Red Hat Enterprise Linux 6 | libuser | Fixed | RHSA-2015:1482 | 23.07.2015 |
| Red Hat Enterprise Linux 7 | libuser | Fixed | RHSA-2015:1483 | 23.07.2015 |
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Дополнительная информация
Статус:
EPSS
1.7 Low
CVSS2
Связанные уязвимости
Incomplete blacklist vulnerability in the chfn function in libuser before 0.56.13-8 and 0.60 before 0.60-7, as used in the userhelper program in the usermode package, allows local users to cause a denial of service (/etc/passwd corruption) via a newline character in the GECOS field.
Incomplete blacklist vulnerability in the chfn function in libuser before 0.56.13-8 and 0.60 before 0.60-7, as used in the userhelper program in the usermode package, allows local users to cause a denial of service (/etc/passwd corruption) via a newline character in the GECOS field.
Incomplete blacklist vulnerability in the chfn function in libuser bef ...
Incomplete blacklist vulnerability in the chfn function in libuser before 0.56.13-8 and 0.60 before 0.60-7, as used in the userhelper program in the usermode package, allows local users to cause a denial of service (/etc/passwd corruption) via a newline character in the GECOS field.
EPSS
1.7 Low
CVSS2