[Xerte-dev] Re: SECURITY PATCH for upload.php

Fri Mar 8 13:46:49 GMT 2013

I’m not sure I’m close enough to the detail to recommend a way forward here, so happy to go with a recommendation, but would like to see it all implemented at once in the svn so we’re not in a position where exporting the svn creates an install that won’t upload anything…

From: xerte-dev-bounces at lists.nottingham.ac.uk [mailto:xerte-dev-bounces at lists.nottingham.ac.uk] On Behalf Of Smith, John
Sent: 08 March 2013 13:26
To: For Xerte technical developers
Subject: [Xerte-dev] Re: SECURITY PATCH for upload.php

I suppose then we could have a script in management that parses the extensions from the xwd files and warns which extensions need to be added to the field in order to make the model fully usable… would that be duplicating and adding to the confusion of having a mime types field in sitedetails too?

Well I’ll work on the basis that I’ll be getting extensions from somewhere and make sure to check session, extension and mime type (based on allowable types for that extension).

One more question, do the error messages (before exit(); ) get fed back to the flash? Should we even include them then as they give a hacker some hint as to why an exploit failed – should it just be “failed”

Regards,

John Smith
Learning Technologist
School of Health & Life Sciences
Glasgow Caledonian University

From: xerte-dev-bounces at lists.nottingham.ac.uk<mailto:xerte-dev-bounces at lists.nottingham.ac.uk> [mailto:xerte-dev-bounces at lists.nottingham.ac.uk] On Behalf Of Julian Tenney
Sent: Friday, March 08, 2013 1:13 PM
To: For Xerte technical developers
Subject: [Xerte-dev] Re: SECURITY PATCH for upload.php

I think my preference would be for a global setting: comma seperated list of allowed types in management.php so we ship a secure product, and people can change the settings if they want to.

From: xerte-dev-bounces at lists.nottingham.ac.uk<mailto:xerte-dev-bounces at lists.nottingham.ac.uk> [mailto:xerte-dev-bounces at lists.nottingham.ac.uk] On Behalf Of Pat @ Pgogy
Sent: 07 March 2013 17:14
To: For Xerte technical developers
Subject: [Xerte-dev] Re: SECURITY PATCH for upload.php

Hello,

Problem is getting a list of types the models support. I think there is a case for saying the model should list the extensions it supports as it is partly their job to do it. This way the model could post the allowed types and the list is generated on the fly?

I agree preventing php is a good thing, but I think the problem is not knowing what types are acceptable is a real curveball

Pgogy Webstuff - http://www.pgogywebstuff.com
Makers of web things of a fair to middling quality

On 7 Mar 2013, at 15:32, "Smith, John" <J.J.Smith at gcu.ac.uk<mailto:J.J.Smith at gcu.ac.uk>> wrote:
Hi Pat,

I didn’t copy your regexp or your select list directly but translated the select code into a comma separated list so that it can be moved elsewhere if required…

I noticed the list in the sitedetails table but it is of Mime Types. I think it would be best practice to use extensions, content headers, mimetypes and any other method available to whitelist the allowable files but I think that might take a bit more work…

I think it is leaving a load of sites out there very vulnerable so we should try to  find a good way to shore this up before the next release. What do you think? I’ll have a go at adding in some code to deal with content headers and mimetypes

Regards,

John Smith
Learning Technologist
School of Health & Life Sciences
Glasgow Caledonian University

From: xerte-dev-bounces at lists.nottingham.ac.uk<mailto:xerte-dev-bounces at lists.nottingham.ac.uk> [mailto:xerte-dev-bounces at lists.nottingham.ac.uk] On Behalf Of Pat @ Pgogy
Sent: Thursday, March 07, 2013 2:54 PM
To: For Xerte technical developers
Subject: [Xerte-dev] Re: SECURITY PATCH for upload.php

Hello,

I hobble the Wordpress version deliberately to only allow a few file types but that isn't the list that full XOT needs (there is in fact, no list, hence the problem).

My reg exp is a bit flaky as well, if you copied that over.

There is a sort of whitelist in the sitedetails table as the media upload properties panel page uses this - but not sure this is the XOT list.

Pgogy Webstuff - http://www.pgogywebstuff.com
Makers of web things of a fair to middling quality

On 7 Mar 2013, at 13:01, "Smith, John" <J.J.Smith at gcu.ac.uk<mailto:J.J.Smith at gcu.ac.uk>> wrote:
Hi,

I’ve just committed a change to upload.php (revision 714) to stop users exploiting a system by uploading php code. I’ve added a whitelist and stuck in the same allowed file extensions that Pat uses in the Wordpress plugins.

Can someone test this and advise if there are any other media types that we want/need to allow?

There was also a session check but exit(); was commented out therefore in an unpatched system ANYONE can post data to upload.php and get some code onto the server. I’ve uncommented this now but does anyone know why it was commented out in the first place?

Regards,

John Smith
Learning Technologist
School of Health & Life Sciences
Glasgow Caledonian University

Glasgow Caledonian University is a registered Scottish charity, number SC021474

Winner: Times Higher Education’s Widening Participation Initiative of the Year 2009 and Herald Society’s Education Initiative of the Year 2009.
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Glasgow Caledonian University is a registered Scottish charity, number SC021474

Winner: Times Higher Education’s Widening Participation Initiative of the Year 2009 and Herald Society’s Education Initiative of the Year 2009.
http://www.gcu.ac.uk/newsevents/news/bycategory/theuniversity/1/name,6219,en.html

Winner: Times Higher Education’s Outstanding Support for Early Career Researchers of the Year 2010, GCU as a lead with Universities Scotland partners.
http://www.gcu.ac.uk/newsevents/news/bycategory/theuniversity/1/name,15691,en.html
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Glasgow Caledonian University is a registered Scottish charity, number SC021474

Winner: Times Higher Education’s Widening Participation Initiative of the Year 2009 and Herald Society’s Education Initiative of the Year 2009.
http://www.gcu.ac.uk/newsevents/news/bycategory/theuniversity/1/name,6219,en.html

Winner: Times Higher Education’s Outstanding Support for Early Career Researchers of the Year 2010, GCU as a lead with Universities Scotland partners.
http://www.gcu.ac.uk/newsevents/news/bycategory/theuniversity/1/name,15691,en.html
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