TITLE:
Webmin "miniserv.pl" Format String Denial of Service Vulnerability

SECUNIA ADVISORY ID:
SA17749

VERIFY ADVISORY:
http://secunia.com/advisories/17749/

CRITICAL:
Less critical

IMPACT:
DoS

WHERE:
>From remote

SOFTWARE:
Webmin 1.x
http://secunia.com/product/1115/

DESCRIPTION:
Jack Louis has discovered a vulnerability in Webmin, which can be
exploited by malicious people to cause a DoS (Denial of Service).

The vulnerability is caused due to a format string error in the
"miniserv.pl" script when logging failed authentication attempts.
This can be exploited to consume a large amount of CPU and memory
resources on a vulnerable system by attempting to login with a
specially crafted username.

It has also been reported that the format string error in the Perl
script can be exploited for code execution purposes. However, this
has not been shown.

The vulnerability has been confirmed in version 1.240. Other versions
may also be affected.

SOLUTION:
Filter traffic to the Webmin web interface (by default port 10000) or
edit the source code to ensure that input is not logged insecurely to
the syslog.

PROVIDED AND/OR DISCOVERED BY:
Jack Louis, Dyad Security

ORIGINAL ADVISORY:
http://www.dyadsecurity.com/webmin-0001.html

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