CVE-2016-5174

CVE: CVE-2016-5174
CWE:
- 20
bugs:
- 579934
repo: 
vccs:
- note: the issue arises from an unhandled user flow and therefore cannot be associated
    with a specific commit, however this is when the commit functionality was originated.
  commit: 7d791652c7ede4209a2014d885148e2713f49bce
fixes:
- note: add code to handle fullscreen stuck issue.
  commit: 104e5ad762f4d2fcf04a33ff8471d77d7b8678bb
bounty:
  date: '2016-09-13 15:04:00.000000000 -04:00'
  amount: 1000.0
  references:
  - http://chromereleases.googleblog.com/2016/09/stable-channel-update-for-desktop_13.html
lessons:
  yagni:
    note: 
    applies: false
  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: This principle might have led to the vulnerability and it is most likely
      that the developer of the related functionality either did not consider the
      flow that would lead to a DOS or the lack of necessity for fixing this particular
      use case was deemed appropriate.
    applies: true
  distrust_input:
    note: Distrusting websites input to push popups and requiring manual authorization
      is the fix to this vulnerability.
    applies: true
  least_privilege:
    note: 
    applies: 
  native_wrappers:
    note: 
    applies: 
  defense_in_depth:
    note: 
    applies: 
  secure_by_default:
    note: Forcing the user to toggle "allow" for every popup may not be the most convenient
      for the user but it is the most secure option
    applies: 
  environment_variables:
    note: 
    applies: 
  security_by_obscurity:
    note: 
    applies: false
  frameworks_are_optional:
    note: 
    applies: 
reviews:
- 2053343003
upvotes: 4
mistakes:
  answer: 'The origin of this vulnerability is the lack of input validation from the
    remote target site. In certain conditions, the remote site was able to push popups
    on to the user''s browser, and have them open without asking for user''s consent.
    This, lack of input was due to improper handling of a particular use case in that
    Flash objects were not filtered for popups and therefore they opened forcibly.
    By doing this, the user is let vulernable to DOS attack (by spamming the host
    browser) and redirects to malicious sites. This is likely due to missing security
    requirements of "Flash" popup handling or the following of yagni principle. The
    fix, follows the mitigations by CWE. However, I noticed that the fix is only partial.
    It has resolved the issue of the fullscreen being stuck but popups remain unhandled,
    which leads me to believe that proper mitigations were not followed and the fix
    is not proper.

    '
  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: '2016-09-25 16:59:07.060000000 -04:00'
subsystem:
  name: UI
  answer: The subsystem where the mistsake is UI
  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: '2016-01-21'
  answer: The reporter noticed that flash objects can create popups which chromium
    does not block popups.
  google: false
  contest: false
  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: false
description: On a browser window, toggle requests go unprocessed which allows attackers
  (remote sites) to create unsuppressed popups causing a DOS (Denial of Service) by
  spamming the browser and causing it to crash. Fullscreen mode would also get stuck
  and you are unable to leave it.
unit_tested:
  fix: false
  code: false
  answer: The original unit test did not test the vulnerability.
  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: The team did not prioritize stopping popups but ensured that fullscreen
    mode would not get stuck. a later ticket was opened to block popups (https://bugs.chromium.org/p/chromium/issues/detail?id=626749)
    but it is still pending and the latest comment has suggested a "WontFix" because
    the issue only occurs in Flash, which is rarely used.
  events:
  - date: '2016-06-10'
    name: Partial Fix
  - date: 
    name: 
  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: 1
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: No, the fix sought to cover a previously uncovered use case (when screen
    is in fullscreen mode). Between VCS and fix, other use cases were handled (minimzed
    screen etc.) However, one interesting thing to note is that the fix was only for
    the issue of the fullscreen getting stuck. Popup blocking has yet still not been
    fixed.
  commits:
  - note: 
    commit: 
  - note: 
    commit: 
  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.