[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: CVE-2015-7519


On 19 February 2016 at 09:35, Linus van Geuns <linus@vangeuns.name> wrote:
> On Thu, Feb 18, 2016 at 8:35 PM, Thorsten Alteholz <debian@alteholz.de> wrote:
>> On irc you wrote:
>> 15:05 < Nirkus> have some old redmine running on squeeze-lts (yeah..) and since the update yesterday the following redmine code bails out with "private method `split' called for nil:NilClass" at the following line:
>> 15:06 < Nirkus> @env['QUERY_STRING'].present? ? @env['QUERY_STRING'] : (@env['REQUEST_URI'].split('?', 2)[1] || '')
>> In CVE-2015-7519[1] it was detected, that it is possible to obtain
>> unauthorized access if you send http variables with "_" instead of "-". More information can be found here[2]. As a solution it was proposed to simply filter out all variables containing an "_". This was already done in mod_cgi of apache[3] and now I applied a similar patch to libapache2-mod-passenger as well.
>> Unfortunately there seems to be software that relies on underscores in variable names. So if you need such variables you might want to use the workaround for apache, described in[2].
> I am only scratching the surface of Ruby, Passenger, Rack/Rails and
> Redminde, so corrections and clarifications welcome. :)
> I am not sure whether REQUEST_URI and QUERY_STRING are actually passed
> as per-request env. variables by Passenger or added to the env hash by
> Rack/Rails.
> Still, this looks like a regression to me, since it removes previously
> available variables, which should not be in scope of CVE-2015-7519.

It is a regression, there's no way for applications using
mod_passenger to work after the latest update. Not only did the update
switch to a native package and drop some documentation, but it broke
the module.

Granted, the package is safer now that it doesn't work.

Raphael Geissert

Reply to: