TITLE:
SELinux "unix_chkpwd" Security Bypass Security Issue

SECUNIA ADVISORY ID:
SA17352

VERIFY ADVISORY:
http://secunia.com/advisories/17352/

CRITICAL:
Not critical

IMPACT:
Security Bypass

WHERE:
Local system

SOFTWARE:
SELinux for Distributions
http://secunia.com/product/5997/

DESCRIPTION:
A security issue has been reported in SELinux, which potentially can
be exploited by malicious, local users to bypass certain security
restrictions.

The security issue is caused due to "unix_chkpwd" failing to prevent
any attempts to use it to guess other users' passwords when SELinux
is enabled without an appropriately configured policy.  Failed guess
attempts are also not logged. This can potentially be exploited by
malicious users to brute-force the passwords of other accounts.

Successful exploitation requires that the policy allows "unix_chkpwd"
to be run by non-privileged users.

SOLUTION:
Grant only trusted users access to affected systems.

Some Linux vendors have issued fixed packages.

PROVIDED AND/OR DISCOVERED BY:
Tomas Mraz

ORIGINAL ADVISORY:
Red Hat Bugzilla:
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=168180

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