Bug #5418: Some properties of WEBrick::HTTPRequest could be malformed

• Status: Assigned
• Priority: Normal
• Assignee: normalperson (Eric Wong)
• Target version: -
• ruby -v: -
• Tags: lib

[nahi (Hiroshi Nakamura)]

Original reported issue: CVE-2011-3187

Users may expect that properties of WEBrick::HTTPRequest to be not
malformed/faked. But at the fact, in current implementation, following
properties can be malformed and faked by HTTP header sent by attacker.

• HTTPRequest#host

  • can be malformed/faked by 'x-forwarded-host'
  • can be faked by 'Host'

• HTTPRequest#port

  • can be faked by 'Host'

• HTTPRequest#server_name

  • can be malformed/faked by 'x-forwarded-server'

• HTTPRequest#remote_ip

  • can be malformed/faked by 'x-forwarded-for' and 'client-ip'

• HTTPRequest#ssl?

  • can be faked by 'Host'

• HTTPRequest#meta_vars (Hash of meta vars such as 'REQUEST_URI')

  • can be malformed/faked by some HTTP headers

Here's the list of reason why we're thinking it's not a
high-priority security bug at this moment.

• For faked data issue, we don't have a way to guarantee that it's not
  faked. So developers of HTTPRequest must aware of that.

• For malformed data issue, it should be a bug of HTTPRequest to be
  fixed, but it's the same problem for x-forwarded-host,
  x-forwarded-server and client-ip. We're offering those data in as-is
  basis from HTTP header so we can expect users handle the data
  properly for their purpose (for dumping to xterm, embedding to HTML,
  etc.)

• And the fix for this bug would be a little complex for quick-fix
  because it's not only x-forwarded-for which causes this issue.
  'client-ip' needs care, too. Documentation would be enough for
  server_name. We think we need general development cycle for fixing
  it.

ref:
https://bugzilla.novell.com/show_bug.cgi?id=673010
http://webservsec.blogspot.com/2011/02/ruby-on-rails-vulnerability.html

[shyouhei (Shyouhei Urabe)]

• Status changed from Open to Assigned

[ko1 (Koichi Sasada)]

• Target version changed from 2.0.0 to 2.1.0

Time up for 2.0.0.

Nahi-san, how about this ticket?

[hsbt (Hiroshi SHIBATA)]

• Target version changed from 2.1.0 to 2.2.0

[naruse (Yui NARUSE)]

• Target version deleted (2.2.0)

[naruse (Yui NARUSE)]

• Assignee changed from nahi (Hiroshi Nakamura) to normalperson (Eric Wong)

As Rails did, webrick seems to need introduce TRUSTED_PROXIES.