Page2Flip 2.5 Session Management

`-----BEGIN PGP SIGNED MESSAGE-----  
Hash: SHA512  
  
Advisory ID: SYSS-2015-032  
Product: Page2Flip  
Vendor: w!ssenswerft GmbH  
Affected Version(s): Premium App 2.5, probably also in Business App   
and Basic App, and in lower versions  
Tested Version(s): Premium App 2.5  
Vulnerability Type: Broken Authentication and Session Management (CWE-930)  
Risk Level: High  
Solution Status: Open  
Vendor Notification: 2015-06-29  
Solution Date:   
Public Disclosure:   
CVE Reference: Not yet assigned  
Author of Advisory: Dr. Erlijn van Genuchten (SySS GmbH)  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
Overview:  
  
With the Page2Flip Web application, it is possible to create e-papers in  
PDF format that can be flicked through digitally. Such e-papers can be  
used for magazines, catalogues, flyers, etc. (see [1]).  
  
The Page2Flip app allows users to log in with valid credentials, even   
when their user accounts have been deleted.  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
Vulnerability Details:  
  
The SySS GmbH was as an administrative user able to delete user accounts.  
However, these users were after that still able to login with their   
credentials when following the normal login procedure.   
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
Proof of Concept (PoC):  
  
Create a user account with known credentials, delete this account and   
login with these credentials.  
  
The POST request for deleting a user is:  
  
POST /settings/users HTTP/1.1  
Host: [host]  
Faces-Request: partial/ajax  
Content-Type: application/x-www-form-urlencoded;charset=UTF-8  
Content-Length: 1042  
Cookie: [cookies]  
  
form_userSettings=form_userSettings&javax.faces.ViewState=-5924384961489816147%3A2243478473205355579&ice.window=9aib95sifa&ice.view=vvgml70e1&icefacesCssUpdates=&form_userSettings%3Aj_idcl=form_userSettings%3AuserTable%3A0%3AdeleteAccount%3Aactionicon&javax.faces.source=form_userSettings%3AuserTable%3A0%3AdeleteAccount%3Aactionicon&javax.faces.partial.event=click&javax.faces.partial.execute=%40all&javax.faces.partial.render=%40all&ice.window=9aib95sifa&ice.view=vvgml70e1&ice.focus=form_userSettings%3AuserTable%3A0%3AdeleteAccount%3Aactionicon&form_userSettings%3AuserTable%3A0%3AdeleteAccount%3Aactionicon=form_userSettings%3AuserTable%3A0%3AdeleteAccount%3Aactionicon&ice.event.target=bimg&ice.event.captured=form_userSettings%3AuserTable%3A0%3AdeleteAccount%3Aactionicon&ice.event.type=onclick&ice.event.alt=false&ice.event.ctrl=false&ice.event.shift=false&ice.event.meta=false&ice.event.x=1368&ice.event.y=373&ice.event.left=true&ice.event.right=false&ice.submit.type=ice.s&ice.sub  
mit.serialization=form&javax.faces.partial.ajax=true  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
Solution:  
  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
Disclosure Timeline:  
  
2015-06-23: Vulnerability discovered  
2013-06-29: Vulnerability reported to vendor  
2015-07-07: Reported vulnerabilities again as the vendor did not respond   
to the first e-mail  
2015-07-14: Reminder sent concerning reported vulnerabilities  
2015-08-24: Public release of security advisory according to the SySS  
Responsible Disclosure Policy  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
References:  
  
[1] Page2Flip homepage  
http://page2flip.de/  
[2] SySS Responsible Disclosure Policy  
https://www.syss.de/en/news/responsible-disclosure-policy/  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
Credits:  
  
Security vulnerability found by Responsible Hacker of the SySS GmbH.  
  
E-Mail: [email protected]  
Public Key: https://www.syss.de/fileadmin/dokumente/Materialien/PGPKeys/Erlijn_vanGenuchten.asc  
Key ID: 0xBD96FF2A  
Key Fingerprint: 17BB 4CED 755A CBB3 2D47 C563 0CA5 8637 BD96 FF2A  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
Disclaimer:  
  
The information provided in this security advisory is provided "as is"   
and without warranty of any kind. Details of this security advisory may  
be updated in order to provide as accurate information as possible. The  
latest version of this security advisory is available on the SySS Web  
site.  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
  
Copyright:  
  
Creative Commons - Attribution (by) - Version 3.0  
URL: http://creativecommons.org/licenses/by/3.0/deed.e  
-----BEGIN PGP SIGNATURE-----  
Version: GnuPG v1  
  
iQIcBAEBCgAGBQJV2x28AAoJEAylhje9lv8q/egP/0vkbb4a+ku5dw/cv9Hx69Ui  
H0bdz1OrSrCQ9z1jXH8/b3mps4ZDxV87NNgxFyY0Z2DUp36JEIhdi/GpdgUUFPm4  
XIe7J1u3HJ6z4M0PEWrFE/Uwx7stQi3nWAhXKKAL66ZwdT6nKlnHOmGTXf2EggS1  
zvmd7nJkMPIfFZ0f1MEbAVMs90ofBqZlTEnB5Nv5sZVHyFnMdTMdfvgp5Xx4kNg/  
ZYQqi/v2v3Zj79TfN0GPRJ+iWBfzinMVOnjLIRiX0i5+z99L5sQO7eELmQxiwbcm  
4zq3smCGDSprguV5+WBarlH1uNGh+E6Rhfn3GkqkPpK622q6dkRSyzfDZ92Cqc6t  
YBLohkR/ypy/HNLOTefG4IOagwWIBzsPlk1W6bMOF1nUdqLW0DqDRsV5Toh2Qv6T  
n0ctOhTmEBi1vVGxEzGEjFgqjADuzXWpPVimZ/Zum4v2MgfN3QYAtkLTDaHIZMMB  
LOYHUvyJm3okpekqHE2ZzUPA5fYq5L2KeNdOidNM7/oUQHj5WYLmRXUbK5glvU4X  
+PTZcA6cxDsoK4rsu7AJR+H1lEEaCVbAP+7NOKi0geuVe98IKxuWU1BFOJiIa2Y8  
qCh8Sz8HhzWrJDk81ob3fvFDdGrHuMBETlcs/m7EFPNvJMwkOY3BePAQacz+yGRt  
dPO8s21bf54II194Db0a  
=jPzu  
-----END PGP SIGNATURE-----  
`