CVE-2015-1287

CVE: CVE-2015-1287
CWE:
- 807
- 17
bugs:
- 419383
repo: 
vccs:
- note: quirks-mode boolean value had been removed but was added back in to debug
    something else
  commit: 4db3aff5023dc64fa963d1d1b4e774352773240e
fixes:
- note: Removes the quirks-mode for CSS MIME types
  commit: 0522e0ad97fd5814fc17353f2e373534c4cfebb1
- note: Part of some browser and UI tests
  commit: f479194866c3d9e08ef245ed0fdd5b9771ce6195
- note: Drops the quirks-mode for CSS MIME types
  commit: ff8366801dd7c887776e084ae7865fd2f68b9cad
bounty:
  date: '2015-07-21 14:00:00.000000000 -04:00'
  amount: 1337.0
  references:
  - http://chromereleases.googleblog.com/2015/07/stable-channel-update_21.html
lessons:
  yagni:
    note: 
    applies: 
  question: |
    Are there any common lessons we have learned from class that apply to this
    vulnerability? In other words, could this vulnerability serve as an example
    of one of those lessons?

    Leave "applies" blank or put false if you did not see that lesson (you do
    not need to put a reason). Put "true" if you feel the lesson applies and put
    a quick explanation of how it applies.

    Don't feel the need to claim that ALL of these apply, but it's pretty likely
    that one or two of them apply.

    If you think of another lesson we covered in class that applies here, feel
    free to give it a small name and add one in the same format as these.
  serial_killer:
    note: 
    applies: 
  complex_inputs:
    note: Vulnerability involved the parsing of CSS from an external source
    applies: true
  distrust_input:
    note: The WebKit should have just used the strict parsing mode from the start
    applies: true
  least_privilege:
    note: 
    applies: 
  native_wrappers:
    note: 
    applies: 
  defense_in_depth:
    note: 
    applies: 
  secure_by_default:
    note: 
    applies: 
  environment_variables:
    note: 
    applies: 
  security_by_obscurity:
    note: 
    applies: 
  frameworks_are_optional:
    note: 
    applies: 
reviews:
- 1136493003
- 733993002
- 1139913002
- 904143002
- 1126133003
upvotes: 10
mistakes:
  answer: "It seems that the original existence of quirks-mode in the first place
    is for the \npurpose of parsing non-standard CSS. Non-standard CSS seems to be
    a sort of legacy\nsupport. \nIn the bug discussion one of the main arguments to
    drop quirks-mode was\nthat Firefox had already done it. This vulnerability is
    a design mistake, quirks-mode\nwas added in for compatibility purposes but it
    turned out that CSS with an incorrect\nMIME type could open up an opportunity
    for an attack.\nIt is possible that quirks-mode could have been fixed to make
    it more secure.\nHowever removing the option entirely fixed the issue with only
    a minor \nimpact on compatibility\n"
  question: |
    In your opinion, after all of this research, what mistakes were made that
    led to this vulnerability? Coding mistakes? Design mistakes?
    Maintainability? Requirements? Miscommunications?

    Look at the CWE entry for this vulnerability and examine the mitigations
    they have written there. Are they doing those? Does the fix look proper?

    Use those questions to inspire your answer. Don't feel obligated to answer
    every one. Write a thoughtful entry here that those ing the software
    engineering industry would find interesting.
announced: '2015-07-22 20:59:16.443000000 -04:00'
subsystem:
  name: WebCore
  answer: Based on directory. Webcore contains css parsing source and is part of WebKit
  question: |
    What subsystems was the mistake in?

    Look at the path of the source code files code that were fixed to get
    directory names. Look at comments in the code. Look at the bug reports how
    the bug report was tagged. Examples: "clipboard", "gpu", "ssl", "speech", "renderer"
discovered:
  date: '2014-08-01'
  answer: Found by filedescriptor@gmail.com
  google: false
  contest: 
  question: |
    How was this vulnerability discovered?

    Go to the bug report and read the conversation to find out how this was
    originally found. Answer in longform below in "answer", fill in the date in
    YYYY-MM-DD, and then determine if the vulnerability was found by a Google
    employee (you can tell from their email address). If it's clear that the
    vulenrability was discovered by a contest, fill in the name there.

    The "automated" flag can be true, false, or nil.
    The "google" flag can be true, false, or nil.

    If there is no evidence as to how this vulnerability was found, then you may
    leave the entries blank except for "answer". Write down where you looked in "answer".
  automated: 
description: "There was a bug in Blink, the webkit used by Chromium that allowed an
  external\nresource to be loaded as CSS and interpreted with or without a correct
  MIME \n(media) type. This bug made it possible for an attacker to leak data by using\na
  CSS string injection. This bug was caused by the use of a method of interpreting\nCSS
  called \"quirks-mode\" which allowed for the parsing of non-standard CSS. \nThe
  bug had been encountered before in the past and an attempt was made to fix it\nby
  using a \"strict-mode\" to parse CSS with an incorrect MIME type. However, it was\ndiscovered
  that the attack was still possible if the attacker could change the\ncharset to
  UTF-16. From my research it looks like quirks-mode had been removed before\nbut
  it caused some issues with other tests and was added back in. Eventually it was
  \nremoved for good, the browser refuses to load cross-origin resources as CSS if
  the\nMIME type is incorrect. \n"
unit_tested:
  fix: false
  code: true
  answer: true
  question: |
    Were automated unit tests involved in this vulnerability?
    Was the original code unit tested, or not unit tested? Did the fix involve
    improving the automated tests?

    For the "code" answer below, look not only at the fix but the surrounding
    code near the fix and determine if and was there were unit tests involved
    for this module.

    For the "fix" answer below, check if the fix for the vulnerability involves
    adding or improving an automated test to ensure this doesn't happen again.
major_events:
  answer: 
  events:
  - date: '2015-02-06'
    name: Drop of quirks-mode was temporarily reverted because it seemed to be causing
      failures in PPAI input event tests which didnt send MIME types
  - date: '2014-12-13'
    name: Fix seems simple yet took a year and a half to be done, finder allegedly
      found a real world example around the time bug exceeded deadline
  question: |
    Please record any major events you found in the history of this
    vulnerability. Was the code rewritten at some point? Was a nearby subsystem
    changed? Did the team change?

    The event doesn't need to be directly related to this vulnerability, rather,
    we want to capture what the development team was dealing with at the time.
curation_level: 0
CWE_instructions: |
  Please go to cwe.mitre.org and find the most specific, appropriate CWE entry
  that describes your vulnerability. (Tip: this may not be a good one to start
  with - spend time understanding this vulnerability before making your choice!)
bounty_instructions: |
  If you came across any indications that a bounty was paid out for this
  vulnerability, fill it out here. Or correct it if the information already here
  was wrong. Otherwise, leave it blank.
interesting_commits:
  answer: 
  commits:
  - note: "This commit makes the CSS parser check for correct syntax of the CSS header.
      \nThis seems relevant because this vulnerability is due to whether non-standard\nCSS
      should be parsed or not.\n"
    commit: a646ba09b67d5510702761622b0239989cc9650d
  question: |
    Are there any interesting commits between your VCC(s) and fix(es)?

    Write a brief (under 100 words) description of why you think this commit was
    interesting in light of the lessons learned from this vulnerability. Any
    emerging themes?

    If there are no interesting commits, demonstrate that you completed this section by explaining what happened between the VCCs and the fix.
curated_instructions: |
  If you are manually editing this file, then you are "curating" it. Set the
  entry below to "true" as soon as you start. This will enable additional
  integrity checks on this file to make sure you fill everything out properly.
  If you are a student, we cannot accept your work as finished unless curated is
  set to true.
upvotes_instructions: |
  For the first round, ignore this upvotes number.

  For the second round of reviewing, you will be giving a certain amount of
  upvotes to each vulnerability you see. Your peers will tell you how
  interesting they think this vulnerability is, and you'll add that to the
  upvotes score on your branch.
announced_instructions: |
  Was there a date that this vulnerability was announced to the world? You can
  find this in changelogs, blogs, bug reports, or perhaps the CVE date. A good
  source for this is Chrome's Stable Release Channel
  (https://chromereleases.googleblog.com/).
  Please enter your date in YYYY-MM-DD format.
fixes_vcc_instructions: |
  Please put the commit hash in "commit" below (see my example in
  CVE-2011-3092.yml). Fixes and VCCs follow the same format.
description_instructions: |
  You can get an initial description from the CVE entry on cve.mitre.org. These
  descriptions are a fine start, but they can be kind of jargony.

  Rewrite this description in your own words. Make it interesting and easy to
  read to anyone with some programming experience. We can always pull up the NVD
  description later to get more technical.

  Try to still be specific in your description, but remove Chromium-specific
  stuff. Remove references to versions, specific filenames, and other jargon
  that outsiders to Chromium would not understand. Technology like "regular
  expressions" is fine, and security phrases like "invalid write" are fine to
  keep too.