Hello Lists,

Sorry for my rude words but...
there  are  already  too  many  websites  that  either don't give us a
possibility  to  get  an  audio  file  instead of those damned captcha
images;  there are lots of others (such as Msn) where the audio is too
distorted  to  be  heard.  It's  not my f***ing problem that you can't
protect  your  audio  against  spammers.  I'm  blind,  you know, and I
*can't*  see  the  image,  because I have no sight at all! And I'm not
alone, there are thousands of us only in the USA.
So  make  conclusions:  if  you make a popular site, one day you might
have deep problems and maybe even lawsuits from people.
Sorry again, it's been just a really painful thing for us for years.

With best regards from Ukraine,
Skype: Francophile
My blog: http://oire.org/menelion (mostly in Russian)
Twitter: http://twitter.com/m_elensule
Facebook: http://facebook.com/menelion

------------ Original message ------------
From: Lists <li...@senseofsecurity.com>
To: php-general@lists.php.net
Date created: , 1:03:06 AM
Subject: [PHP] PHPCaptcha / Securimage 2.0.2 - Authentication Bypass - 

Sense of Security - Security Advisory - SOS-11-007

Release Date.               20-May-2011
Last Update.                -
Vendor Notification Date.   04-Apr-2011
Product.                    Securimage / PHPCaptcha 
Platform.                   PHP
Affected versions.          1.0.4 - 2.0.2
Severity Rating.            Medium
Impact.                     Authentication bypass
Attack Vector.             Remote without authentication
Solution Status.            Vendor workaround 
                            (remove securimage_play.php)
CVE reference.             Not yet assigned

PHPCaptcha, also known as Securimage, is a popular Open Source PHP
CAPTCHA library. It is also used in popular WordPress plugins such as
the 'Fast Secure Contact Form'. Insufficient distortion in the audio
version of the CAPTCHA allows an attacker to quickly decode the CAPTCHA
by performing basic binary analysis of the generated audio file. The
issue is compounded by the fact that even if the audio feature of the
CAPTCHA has been disabled, it can still be accessed by forceful
browsing to the /secure_play.php URI.

Proof of Concept.
Proof of concept code that works against the example_form.php page and
the MP3 file format provided with the standard PHPCaptcha package 
available from www.phpcaptcha.org is available at:


Proof of concept code is only available for the MP3 version of the
audio, however the WAV audio format is also affected by the same

Remove the script securimage_play.php and disable the use of the Audio

Discovered by.
Phil Taylor from Sense of Security Labs.

About us.
Sense of Security is a leading provider of information security and 
risk management solutions. Our team has expert skills in assessment
and assurance, strategy and architecture, and deployment through to
ongoing management. We are Australia's premier application penetration
testing firm and trusted IT security advisor to many of the country's
largest organisations.

Sense of Security Pty Ltd 
Level 8, 66 King St
Sydney NSW 2000

T: +61 (0)2 9290 4444
F: +61 (0)2 9290 4455
W: http://www.senseofsecurity.com.au
E: i...@senseofsecurity.com.au
Twitter: @ITsecurityAU

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