Possible Information Leak Vulnerability in Action View

Metadata

medium
5.0
actionview
CVE-2016-2097
groups.google.com
2016-02-29
2017-06-16 19:18
CVE-2016-2097 rails
CVE-2016-2097 ruby-actionpack-3.2
CVE-2016-2097 ruby-actionpack-2.3
Possible Information Leak Vulnerability in Action View
CVE-2016-2097
2017-04-01 19:11
2017-01-31 17:03
2017-01-05 20:15

Description


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 the 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!

Am I vulnerable?

The constraints below list the versions that this vulnerability is patched in, and versions that are unaffected. If a patch is ready but unrealeased, then it is pending.

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Affected package information

Package Patched in Unaffected in
actionview ~> 4.1.14, >= 4.1.14.2 >= 4.2.0