TITLE:
TWiki Restricted Content Access and Denial of Service

SECUNIA ADVISORY ID:
SA19410

VERIFY ADVISORY:
http://secunia.com/advisories/19410/

CRITICAL:
Moderately critical

IMPACT:
Security Bypass, DoS

WHERE:
>From remote

SOFTWARE:
TWiki
http://secunia.com/product/4248/

DESCRIPTION:
A vulnerability and a security issue have been reported in TWiki,
which can be exploited by malicious people to cause a DoS (Denial of
Service) and bypass certain security restrictions.

1) The problem is that it is possible to view restricted content via
the rdiff and preview scripts.

Example:
http://[host]/bin/preview/[restricted content]/WebHome?action=foo

The security issue has been reported in releases TWikiRelease04x00x01
and TWikiRelease04x00x00.

2) An error in the handling of circular references for the "%INCLUDE"
statement can be exploited to cause an infinite recursion and consume
a large amount of memory resources on a vulnerable system by
supplying a URL which references itself.

The vulnerability has been reported in the following releases:
* TWikiRelease04x00x01
* TWikiRelease04x00x00
* TWikiRelease04Sep2004
* TWikiRelease03Sep2004
* TWikiRelease02Sep2004
* TWikiRelease01Sep2004
* TWikiRelease01Feb2003
* TWikiRelease01Dec2001
* TWikiRelease01Sep2001

SOLUTION:
Apply patches (see vendor advisories).

The vulnerability and the security issue will also be fixed in the
upcoming 4.0.2 version.

PROVIDED AND/OR DISCOVERED BY:
The vendor credits:
1) Sergej Zagursky and Steffen Poulsen
2) Kenneth Lavrsen

ORIGINAL ADVISORY:
1)
http://twiki.org/cgi-bin/view/Codev/SecurityAlertTWiki4RdiffPreviewAccess
2)
http://twiki.org/cgi-bin/view/Codev/SecurityAdvisoryDosAttackWithInclude

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