To respond on this issue: There are diffent types of security within Domino applications: - First of all you have the Database ACL which take care of the accessrights of the complete database. This one is the most important one since this one defines who can access the database and on which level, and who cannot access at all. - Secondly you can protect the diffent design elements like views and forms, which are required to view the data in the database. The only thing you protect is the ability of a user to use these design elements to view data, not the data itself. - Last one is the protection of the actual data which is stored in documents. These documents can be protected by using reader and author fields. There are a view more ways to protect data, but these three are the most used ones. The conclusion you can make is that the only way to actually protect your data is to define your database ACL correctly and make use of reader and author fields to define who can view and edit the different documents. All other security options are only procecting the different design element and not the actual data. Always keep this in mind while designing applications on the Lotus Domino platform! Bas Welman & Willem Jan Allaart IT Development Kelly Services International NGSSoftware Insight Security Research Advisory Name: Lotus Domino View ACL by-pass Systems Affected: Lotus Domino Web Server 5.x on all operating systems Severity: Possibly high Vendor URL: http://www.lotus.com/ Author: David Litchfield (davidat_private) Date: 29th October 2001 Advisory number: #NISR29102001C Description *********** Lotus Domino is an Application server designed to aid workgroups and collaboration on projects and offers SMTP, POP3, IMAP, LDAP and web services that allow users to interact with Lotus Notes databases. A Lotus Notes database contains documents which are organized into views. Access control lists can be applied to the database itself, views and documents. If a user has been denied access to a view, NISR have discovered that it is possible to by-pass the permissions set on that view and access the documents one would expect it to protect. Details ******* The reason this vulnerability exists is because even though a document might exist in one view it can be accessed from any view, that is all documents in a Lotus Notes database can be access from any view. As an example of this examine the Statistics Reporting database, statrep.nsf. If you open the Events view: http://server/statrep.nsf/136/?OpenView some documents will exist. (136 is the NoteID of the Events view) If you open the hidden $Alarms view http://server/statrep.nsf/$alarms/?OpenView no documents exist. Request one of the documents from the Events view http://server/statrep.nsf/136/8F6?OpenDocument (8F6 is the NoteID of the first document) Note the text of this document and then request http://server/statrep.nsf/$alarms/8F6?OpenDocument The same document is returned, even though $alarms has no documents. Now,if you apply access controls on the Events view and request http://server/statrep.nsf/136/8F6?OpenDocument the server will return an Illegal Argument exeception error. This is due to the fact that the server expects credentials. However, requesting http://server/statrep.nsf/$alarms/8F6?OpenDocument still returns the document even though access to the view the document exists in disallowed. The reason we can request any document through any view is due to the fact that a NoteID is simply a pointer to a location in the database file and as long as the server receives its expected syntax, i.e. database, view then document it will service the request. By making a request with a NoteID we're simply forcing the server to return the contents of an arbitrary location within the file. Fix Information *************** The solution to this problem is to ensure that,if you are applying ACLs to a view, the documents in that view are also protected. Lotus were informed about this issue and their response was that applying ACLs to a view protected only the view and not the documents themselves and that they, too, should have access control lists applied. NISR consider that the difference between expected and actual behaviour is considerable enough that many Lotus administrators may be caught out by this and should ensure that their sensitive documents are indeed protected. A check for this issue already exists in DominoScan, NGSSoftware's Lotus Domino application security scanner, of which, more information is available from http://www.nextgenss.com/dominoscan.html . NISR have also written a white paper on how to secure Lotus Domino's web server available from http://www.nextgenss.com/papers.html -----------------------------------------------------
This archive was generated by hypermail 2b30 : Wed Oct 31 2001 - 11:55:20 PST