Penetration Testing mailing list archives
RE: Client/Server application that does not authenticate users
From: "Dinis Cruz" <dinis () ddplus net>
Date: Sat, 14 Aug 2004 00:49:37 +0100
Then you can just write a little script to highjack (i.e. 'patch') that function in the OS (or in the application's exe) and you will be able to impersonate who ever you want without rebooting into another user. This could also be used to do an automated brute force username attack (since you don't need passwords) Dinis Cruz .Net Security Consultant DDPlus
-----Original Message----- From: Brian Erdelyi [mailto:brian_erdelyi () yahoo com] Sent: 13 August 2004 23:41 To: Dinis Cruz Subject: RE: Client/Server application that does not authenticate users I had thought of this as well consider the application makes use of environment viarables. I did test and confirmed it is not using the Windows environment variable "USERNAME". The vendor has reported thay use a WIN32 API called GetUserName. --- Dinis Cruz <dinis () ddplus net> wrote:I knew of an web app that got the username for the user variable "Username" Guess what would happen in you typed in the client workstation "Set Username=Admin" :) For guidelines check out the OWASP documents: Top 10 (http://www.owasp.org/documentation/topten.html), Testing guide (http://www.owasp.org/documentation/testing.html), the ISO 17799 Project (http://www.owasp.org/standards/iso17799.html) and the app sec FAQ (http://www.owasp.org/documentation/faq.html) Hope this helps Best regards Dinis Cruz .Net Security Consultant DDPlus-----Original Message----- From: Brian Erdelyi[mailto:brian_erdelyi () yahoo com]Sent: 13 August 2004 11:58 To: Dinis Cruz; pen-test () securityfocus com Subject: RE: Client/Server application that doesnot authenticate usersI am working with the vendor on this.Unfortunately,I was assured by the cendor that the applicationdoesauthenticate users and uses accesscontrol lists to assign permissions. They claimed I was was usinganuncommon interpretation of the term"authentication".The next level of support disagreed with my use oftheterm "vulnerability". The server does ask for a username (the client automatically forwards the Windows username of the currently logged on computer) but no password is requested or sent at any point. This is by designofthe application (which from my perspective is seriously flawed for an application that allowsusersto sell and trade millions of dollars worth ofbonds).I will give the vendor some time to analyse the description I have provided to them and respond. I'd like to provide some very specific suggestionsandguidance on how other applications are designedandcoded to authenticate users. Is there an RFC on secure programming? --- Dinis Cruz <dinis () ddplus net> wrote:Quite common. The other major mistake that most do is to relyonthe Client's GUI to enforce the 'security boundaries' of the client application (for example: they rely on the fact that the user's GUIdoesn'thave the functionality to change passwords (including the administrators),soif such a request is made it must be from a valid source....) But, the big question is: "what happens next?" Are they going to tell their customers thattheirdata could had been (or was) compromised? Dinis Cruz .Net Security Consultant DDPlus__________________________________ Do you Yahoo!? Yahoo! Mail is new and improved - Check it out! http://promotions.yahoo.com/new_mail__________________________________ Do you Yahoo!? Yahoo! Mail - 50x more storage than other providers! http://promotions.yahoo.com/new_mail
Current thread:
- Client/Server application that does not authenticate users Brian Erdelyi (Aug 12)
- RE: Client/Server application that does not authenticate users Dinis Cruz (Aug 16)
- <Possible follow-ups>
- RE: Client/Server application that does not authenticate users Brian Erdelyi (Aug 16)
- RE: Client/Server application that does not authenticate users Dinis Cruz (Aug 16)
- RE: Client/Server application that does not authenticate users Dinis Cruz (Aug 16)