CVE-2016-2097

Open Source Vulnerabilities CVE-2016-2097

Directory traversal vulnerability in Action View in Ruby on Rails before 3.2.22.2 and 4.x before 4.1.14.2 allows remote attackers to read arbitrary files by leveraging an application's unrestricted use of the render method and providing a .. (dot dot) in a pathname. NOTE: this vulnerability exists because of an incomplete fix for CVE-2016-0752.

Open Source Vulnerabilities GHSA-vx9j-46rh-fqr8

There is a possible directory traversal and information leak vulnerability in Action View. This was meant to be fixed on CVE-2016-0752. However the 3.2 patch was not covering all possible scenarios. This vulnerability has been assigned the CVE identifier CVE-2016-2097. Versions Affected: 3.2.x, 4.0.x, 4.1.x Not affected: 4.2+ Fixed Versions: 3.2.22.2, 4.1.14.2 Impact ------ Applications that pass unverified user input to the `render` method in a controller may be vulnerable to an information leak vulnerability. Impacted code will look something like this: ```ruby def index render params[:id] end ``` Carefully crafted requests can cause the above code to render files from unexpected places like outside the application's view directory, and can possibly escalate this to a remote code execution attack. All users running an affected release should either upgrade or use one of the workarounds immediately. Releases -------- The FIXED releases are available at the normal locations. Workarounds ----------- A workaround to this issue is to not pass arbitrary user input to the `render` method. Instead, verify that data before passing it to the `render` method. For example, change this: ```ruby def index render params[:id] end ``` To this: ```ruby def index render verify_template(params[:id]) end private def verify_template(name) # add verification logic particular to your application here end ``` Patches ------- To aid users who aren't able to upgrade immediately we have provided patches for it. It is in git-am format and consist of a single changeset. * 3-2-render_data_leak_2.patch - Patch for 3.2 series * 4-1-render_data_leak_2.patch - Patch for 4.1 series Credits ------- Thanks to both Jyoti Singh and Tobias Kraze from makandra for reporting this and working with us in the patch!