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ShAnKaR: Simle machines forum CAPTCHA bypass and PHP injection
From: 3APA3A <3APA3A () SECURITY NNOV RU>
Date: Mon, 18 Jun 2007 13:49:53 +0400

Dear bugtraq () securityfocus com,

  ShAnKaR  <shankar  at shankar.name> reported vulnerabilities in Simple
  Machines Forum 1.1.2 (aka SMF) http://www.simplemachines.org/

  Original advisory (in Russian):
  http://securityvulns.ru/Rdocument271.html

1. Weak sound-based CAPTCHA protection

   In  this engine sound CAPTCHA based automated registration protection
   is  implemented  with  a  WAV file, generated by concatenation of few
   different  sound  files.  Developers  use WAV file randomization, but
   this   randomization   is   insufficient   and  can  be  bypassed  by
   bruteforcing with known sound templates.

[blah () localhost smfh]$ ./captcha.pl http://localhost/smf/
nnrbv
created in 1.41827201843262 seconds
[andrey () localhost smfh]$ ./captcha.pl http://localhost/smf/
vpubu
created in 1.49515509605408 seconds
[andrey () localhost smfh]$ ./captcha.pl http://localhost/smf/
ntfhh
created in 2.31928586959839 seconds
[andrey () localhost smfh]$ ./captcha.pl http://localhost/smf/
egudz
created in 0.823321104049683 seconds

  As  it  can  be  seen,  bruteforce usually takes only 1-2 seconds. See
  script attached.

2. PHP injection

There  is  a  possibility  to  execute  any  PHP code during creation or
editing of forum message.
(no further details is given by advisory author).




-- 
http://securityvulns.com/
         /\_/\
        { , . }     |\
+--oQQo->{ ^ }<-----+ \
|  ZARAZA  U  3APA3A   } You know my name - look up my number (The Beatles)
+-------------o66o--+ /
                    |/

Attachment: capcha.pl
Description:

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