======= Summary ======= Name: SharePoint Team Services source code disclosure through download facility Release Date: 21 October 2009 Reference: NGS00532 Discover: Daniel Martin <daniel (at) ngssoftware (dot) com [email concealed]> Vendor: Microsoft Systems Affected: SharePoint 2007 (12.0.0.6219, 12.0.0.4518 and possibly others) Risk: Medium Status: Reported ======== TimeLine ======== Discovered: 17 September 2008 Released: 2 October 2008 Approved: 3 October 2008 Reported: 8 October 2008 Fixed: Published: 23 October 2009 =========== Description =========== Microsoft SharePoint is a browser-based collaboration and document management platform. It can be used to host web sites that access shared workspaces and documents, as well as specialized applications like wikis and blogs from a browser. It was found that the download facility of Microsoft SharePoint Team Services can be abused to reveal the source code of ASP.NET files. ================= Technical Details ================= SharePoint Team Services stores a variety of files in its backend database. These files include site templates, custom ASP.NET pages and documents that users of the application upload to the document libraries. Insufficient validation in the input parameters of the download facility can result in the source code of ASP.NET files being disclosed. For example, the source code of the default ASP.NET page available after installing the product (http://server/Pages/Default.aspx) can be obtained by issuing the following request: http://server/_layouts/download.aspx?SourceUrl=/Pages/Default.aspx&Sourc e=http://server/Pages/Default.aspx&FldUrl= In order to retrieve the source code any file stored in the backend database (files whose path does not start with /_layout/) it is sufficient to craft a request that follows this pattern: http://server/_layouts/download.aspx?SourceUrl=<relative_path>&Source=<f ull_path>&FldUrl= This bug can result in disclosure of sensitive information that can be used by an attacker targeting the system. For instance the PublicKeyTokens of the ASP.NET assemblies deployed in the server can be revealed enabling an attacker to upload a malicious file that makes use of them. =============== Fix Information =============== It is advised that the source code of any bespoke ASP.NET file deployed in the system is reviewed to ensure that no sensitive information would be reviewed if an attacker abuses the download facility of the framework. Additionally access on a need-to-know basis to SharePoint systems is advised. No workarounds exist at this point. However Microsoft has been contacted so they can produce a fix for their customers. NGS has been advised that although this issue will not be patched until the next release of SharePoint, Microsoft has addressed the design issues around it in a Knowledge Base article (KB976829) about security considerations when running SharePoint that can be found at: http://go.microsoft.com/fwlink/?LinkId=167936 NGS Software wants to thank the MSRC team and Charles Weidner in particular for their support in clarifying this issue. NGSSoftware Insight Security Research http://www.ngssoftware.com/ http://www.databasesecurity.com/ http://www.nextgenss.com/ +44(0)208 401 0070 -- E-MAIL DISCLAIMER The information contained in this email and any subsequent correspondence is private, is solely for the intended recipient(s) and may contain confidential or privileged information. For those other than the intended recipient(s), any disclosure, copying, distribution, or any other action taken, or omitted to be taken, in reliance on such information is prohibited and may be unlawful. If you are not the intended recipient and have received this message in error, please inform the sender and delete this mail and any attachments. The views expressed in this email do not necessarily reflect NGS policy. NGS accepts no liability or responsibility for any onward transmission or use of emails and attachments having left the NGS domain. NGS and NGSSoftware are trading names of Next Generation Security Software Ltd. Registered office address: Manchester Technology Centre, Oxford Road, Manchester, M1 7EF with Company Number 04225835 and VAT Number 783096402