iDEFENSE Security Advisory 10.15.02:
http://www.idefense.com/advisory/10.15.02.txt
DoS and Directory Traversal Vulnerabilities in WebServer 4 Everyone
October 15, 2002

I. BACKGROUND

RadioBird Software's WebServer 4 Everyone is a free "Powerful,
MultiClient, yet Easy to handle and maintain, WebServer.". It is
available for download at http://www.freeware.lt/ .

II. DESCRIPTION

Issue 1:

Improper bounds checking allow attackers to launch a denial of
service (DoS) attack, causing the web server to crash. The condition
is triggered when the software receives a request for a long
filename, such as GET /AAAAAAAA...3000...AAAA HTTP/1.1 .

Issue 2:

A directory traversal issue exists. The software can be duped into
serving a restricted file. This is done if an attacker issues a
directory traversal request with the hexadecimal representation for
the front slash character (%2F). For example, if the URL
http://target.server/%2f..%2f..%2f../winnt/repair/sam were sent to a
target server, the SAM table would be retrieved.

A vulnerability exists that provides attackers access to arbitrary
files on the server running the application. 


III. ANALYSIS

For Issue 1, exploitation could allow an attacker to deny legitimate
users access to the server and the contents that it provides.

For Issue 2, exploitation allows an attacker to obtain sensitive
information, such as the Windows NT SAM table. This kind of
information can allow further compromise of the targeted host.
Sensitive information such as credit cards can also be retrieved.

Customers should note that an remote user with access to the
application can launch these attacks.

IV. DETECTION

iDEFENSE has confirmed the existence of both vulnerabilities in
WebServer 4 Everyone, versions 1.23 and 1.27. Earlier versions are
likely affected, as well. 

V. VENDOR FIX

Leonardas Survila of Radiobird Software released WebServer 4
Everyone, version 1.30, which fixes the problems. It is downloadable
at ftp://ftp.freeware.lt/anonymous/Soft/w4asetup.exe.

VI. CVE INFORMATION

The Mitre Corp.'s Common Vulnerabilities and Exposures (CVE) Project 
assigned the identification number CAN-2002-1212 to Issue 1 and
CAN-2002-1213 to Issue 2.

VII. DISCLOSURE TIMELINE

10/06/2002	Issues disclosed to iDEFENSE
10/14/2002	Vendor notified via e-mail to ulterior@freeware.lt
10/14/2002	iDEFENSE clients notified
10/14/2002	Response received from Leonardas Survila
(leonardass@iki.lt)
10/15/2002	Vendor fix created
10/15/2002	Coordinated public disclosure

VIII. CREDIT

Tamer Sahin (ts@securityoffice.net) discovered both of these
vulnerabilities.


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- -dave

David Endler, CISSP
Director, Technical Intelligence
iDEFENSE, Inc.
14151 Newbrook Drive
Suite 100
Chantilly, VA 20151
voice: 703-344-2632
fax: 703-961-1071

dendler@idefense.com
www.idefense.com

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