The post is related to the image resize vulnerability fix introduced in Sitecore 7.5. To read more about the Sitecore fix go to the Release notes page and search for “Media request protection”. While I was holding off for a number of months on the publication of the post as it puts the attack vector in plainer sight that I would like it to be (while the community figured out how to work with Media Resizing in a neat way) – but recently I’ve seen voices raised considering turning the Media Request protection off which I hope you will not be doing after reading this post. The post will also tell you how to enable such security on your older versions of Sitecore.
So here’s the story…. At some point in Cognifide we have performed a research around Sitecore security and one of my colleagues (Marek) found out that you could easily kill any Sitecore instance by performing an image resize attack on it. While the CMS did some rudimentary checks and limited the values of height and width you could still perform an attack by harvesting the images from the site and perform multiple parallel & iterative size increase or just plain use the scale parameter to achieve any image size. A result of such attack would be a a denial of service due to 100% CPU & memory usage and would potentially allow for filling the server drive by creating the endless number of scaling calls.
Marek was even kind enough to provide a proof of concept code that confirmed the hypothesis by performing attack on a few of our internal servers. The program would load the home page; parse to find images linked from it and perform resizing of the images in a number threads.
Psst… Mike made me add the image – supposedly without it I’m not as cool as Stephen!
Following the discovery I’ve attempted to remedy the problem and as a consequence came up with the solution which I have recently put on GitHub – ImageGuard which signs the rendered media links that use any of the resizing/scaling capabilities and filters all request that try to resize/scale, allowing the sizing only when the hash matches and provided it to Sitecore.
This solution is nowhere as complete as the one that was later provided by Sitecore – starting from version 7.5 – still I think it’s still worth making it public to allows for older versions of Sitecore to be guarded against this type of attacks. Read the rest of this article »
In one of my previous posts I described how to create reports in Sitecore PowerShell Extensions (SPE for short) that allow you to leverage the joint power of Sitecore and PowerShell to deliver complete and elegant reports in little to no time. In this post I’ll tell you how to take this a step further and operationalize them into full blown Sitecore Desktop applications.
The secret sauce is in the actions you can place on the report, the additional parameters that I haven’t mentioned in the previous post, and the use of Sitecore rules engine with some rules that come with SPE.
For the purpose of this post I will limit the scripts to samples that are (mostly) in the vanilla SPE deployment.
Let’s begin with describing the actions and how you can configure them to appear in your reports.
What are report actions?
Actions are simply commands powered by scripts and with visibility dependent on certain conditions like the .Net class of the object that is displayed or perhaps other session settings.
You define an action as a script located in an SPE script library and appears in the Actions panel. In the simplest scenario the action would appear when the script library name matches the .Net class name of the items displayed. In the above scenario the actions are placed under
/Platform/Internal/List View/Ribbon/Item/ where Platform is the module and Item is a script library. Let’s take a look at the script here
/Platform/Internal/List View/Ribbon/Item/Open Read the rest of this article »
This post describes how you can deliver JSON/XML/HTML APIs quickly with Sitecore PowerShell Extensions.
Technically this was also available earlier but the API was not refined to the state it is now.
As Sitecore is constantly progressing from predominantly serving as a CMS towards becoming a mobile and web application delivery platform (which is very apparent by the recent increase of SPEAK popularity, the introduction of Item Web API and the app centric nature of the new Sitecore 8 interface there is an increased need to rapidly deliver APIs for those those front end applications to work seamlessly with the CMS back-end.
PowerShell Extensions can help you with that move by enabling rapid prototyping of APIs that are either JSON or XML in nature.
How to make scripts available for the Web API?
This functionality is available in Sitecore PowerShell Extensions starting from version 2.5, however I was never happy with how it worked and how the URLs were structured. With the Modules functionality introduced in 2.8 it was a good time to model it properly for SPE 3.0.
To make a script callable through the v2 of the API you need to place it in an Enabled module in the
Web API integration point library.
Read the rest of this article »
This is just a short post to supplement the “Working with Sitecore items in PowerShell Extensions” as we now have a new cmdlet of retrieving items in SPE 3.0.
Find-Item cmdlet allows you to leverage the glorious new search API Sitecore introduced in the 7.0 version of its CMS to retrieve items using the Sitecore Content Search indexes.
You will find the available parameters on it as follows:
-Index – index name – ISE supports index name auto completion
-Where – Dynamic Linq syntax as specified in this blog
-WhereValues – array of objects for Dynamic Linq
-OrderBy – Dynamic Linq syntax ordering parameter
-First – number of results to return
-Skip – number of results to skip before returning the rest of results.
-Criteria – simple search criteria in the following example form:
Read the rest of this article »
Recently the Sitecore PowerShell Team has been reflecting on the progress of the Sitecore PowerShell Extensions (SPE) module. We appreciate all the feedback and contributions from the community. Without the many great people in the community, the module just wouldn’t be where it is today. The team is proud of the accomplishments for a module developed purely by the community with no formal Sitecore support.
The new year has revealed some exciting news out on the Marketplace for SPE.
The community is vocal!
If there is anything worth mentioning about the module it IS the amazing community!
From what we could find between all of us we have created over 90 articles and videos about the Sitecore PowerShell Extensions.
Together we’ve talked about he module at least at 3 conferences (both times times Sitecore Virtual User Summit was organized and again on Sitecore SUGCON) and a number of times on various Sitecore User Groups. There is plenty of material on YouTube when you search for Sitecore PowerShell. Especially interesting is the 9 episodes mini series on the module usage by Michael West and a comprehensive summary of the module capability by Michael Reynolds. The number of YouTube entries about SPE is now round 15 videos.
And you’re hungry for content!
Our community content reference page have been visited 9722 times over the past year with the number gradually growing to 1343 page views last month alone.
You’re visiting us mostly from United States, United Kingdom and India. Read the rest of this article »
Since we’ve seen some interest from developers wanting to join the Sitecore PowerShell Extensions team, I thought it might be worth documenting how my development environment is put together to allow for easier on-boarding of new members (Yes, we’re hiring! No, we can’t pay you ;) ). Maybe you just want to compile it yourself to make sure we’re not up to no good, or just plain see inside and play with it…
First of all you need to have Sitecore installed somewhere (obviously). For the purpose of examples I’ll assume your instance is located at C:\inetpub\wwwroot\Sitecore8\ and has the 3 standard folders Data, Databases and Website in them as it normally has. For that very same reason I’ll also assume that your Sitecore PowerShell Extensions project folder is located at C:\Projects\SitecorePowerShell\
1) Seed your Sitecore instance
First step that I always perform when I setup a new environment is to seed the Sitecore instance with the items required which is best done by installing the latest release of PowerShell Extensions.
2) Set up Sitecore SPE folders to use the latest files you’re working on
I’m really excited to see the 3.0 version of Sitecore PowerShell Extensions released. There have been more effort, love and sweat poured into this version by the whole team than I would ever expect. This blog has been written to assert the smoothest upgrade experience possible. While we’re always striving for the smoothest upgrade possible – this version introduces some changes that require you to perform a manual step or two. While those could be automated to a degree, making those manual was a conscious choice as I didn’t want to break e.g. your Insite instance that stores some of its files in the “Console” sub-folder of the Website folder.
Before upgrading your instance from Sitecore PowerShell Extensions 2.x to 3.0 please make sure you have your scripts backed up as the upgrade process might cause some of your scripts to be removed. This is especially true if you used the integration script libraries and you are upgrading from SPE 2.7 or earlier. If you’re upgrading from version 2.8 and your script live in your own modules You should be safe although it’s always smart to back up.
The steps you need to take prior or after installing the new version of the PowerShell Extensions:
You MUST delete the following folder from your sitecore Website folders:
IMPACT: If you will not delete that folder or the contents of that folder the PowerShell Extensions applications might no longer work or produce unexpected results
You SHOULD delete the content of the following folder:
IMPACT: Should you not remove the folder – the PowerShell services might be available from both the old URL and the new URL available at: “\sitecore modules\PowerShell\Services\”
You CAN delete the following folders:
IMPACT: Those folders now exist under “\sitecore modules\PowerShell\” but their existence in the previous location does not have any impact other than taking space on the server,
That is pretty much it. I hope to blog about the new features shortly as there is plenty of them and the whole PowerShell Extensions team is really excited to make those available for you.
This has been on my plate for a while and to be honest I’m not sure what took me so long as it literally took around 4 hours from start to completion which I consider a testament to how easy it is to create additional integrations with PowerShell akin to the Gutter integration or the login/logout integration Michael West has recently introduced in the platform.
What this integration allows you to do is to eliminate the need for code deployment when you’re in need for a quick action here and there for when a user executes a workflow command.
You might find this article helpful by a Cognifide colleague of mine. I especially like this image which illustrates nicely where actions fit in a Sitecore workflow.
They are effectively little bits of code that get executed automatically when a user triggers a command.
Read the rest of this article »
It’s been a while since my last summary on April 2012 but finally getting to update the Reference page with the latest community summary for Sitecore PowerShell Extensions.
Following are the updates I will be pushing onto the reference page I’m trying to keep up to date and failing miserably most of the time. Read the rest of this article »
A large problem with Sitecore PowerShell Extensions up to version 3.0 was the lack of proper separation of solutions provided on top of it from the core of the module. The problem is that all integrations look for scripts in the main Script Library but they look for them solely in their single libraries. The specification outlined in this blog aims at solving this issue. Read the rest of this article »