Ph0rum phorum_uriauth replay attack

[Konstantin Gavrilenko <mlists () arhont com>]

Arhont Ltd.- Information Security

Arhont Advisory by:     Konstantin Gavrilenko (http://www.arhont.com)
Advisory:               Ph0rum phorum_uriauth replay attack
Class:                  design bug ?
Version:                4.3.7
Model Specific:         Other version might have the same bug
Contact Date:           11/05/2004 (email sent to tomaz () phorum org)
PD* release date:       19/05/2004

DETAILS:

It is possible to relogin into the previously not loged out sessions in 
Ph0rum udner certain conditions. Two criterias have to be fulfilled:
- the member has to leave the phorum without logging out.
- you have to intercept the hash of his not logged out session or grep
  it out of web-seerver logs

~ e.g.
the intercepted URL or taken straight out of the apache logs
http://xxx.xxx.xxx/phorum/profile.php?f=1&id=2&phorum_uriauth=testuser%3Aeb5cd67f6daf1f35d45a24a36355f4b1

post it into mozilla/Opera and you are in. Works both for ph0rum user 
and admin.

maybe it is worthwile to add an auto-expire function for sessions?


Risk Factor: Low/Medium

Workarounds: Always log out :)


*According to the Arhont Ltd. policy, all of the found vulnerabilities
and security issues will be reported to the manufacturer 7 days before
releasing them to the public domains (such as CERT and BUGTRAQ).

If you would like to get more information about this issue, please do
not hesitate to contact Arhont team.




--
Respectfully,
Konstantin V. Gavrilenko

Arhont Ltd - Information Security

web:    http://www.arhont.com
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e-mail: k.gavrilenko () arhont com

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