CVE-2016-1631

CVE: CVE-2016-1631
CWE:
- 284
- 264
bugs:
- 569496
repo: 
vccs:
- note: The file's introduction into the repository
  commit: cd2af395e8429a30bcee9e7ad7ec9f4b680c924d
fixes:
- note: Implemented suspension of callbacks and resource loading
  commit: dd77c2a41c72589d929db0592565125ca629fb2c
bounty:
  date: '2016-03-02'
  amount: 7500.0
  references:
  - http://chromereleases.googleblog.com/2016/03/stable-channel-update.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: 
    applies: 
  distrust_input:
    note: |
      The vulnerability involves nested modals having cross-side scripting vulnerabilities.
      The contents of the modal message should be treated as malicious.
    applies: true
  least_privilege:
    note: 'The nested message modals were allowed to bypass the the Same Origin Policy.

      '
    applies: true
  native_wrappers:
    note: 
    applies: 
  defense_in_depth:
    note: 
    applies: 
  secure_by_default:
    note: 
    applies: 
  cognitive_complexity:
    note: "The vulnerability involves the use of many different components inside
      of a \nrecursive loop that may cause state changes. The state has to be handeled
      carefully\nin order to provide protections inside the nested loop and then restore
      functionality\nonce the loop has ended.\n"
    applies: true
  environment_variables:
    note: 
    applies: 
  security_by_obscurity:
    note: 
    applies: 
  frameworks_are_optional:
    note: 
    applies: 
reviews:
- 1691513004
- 1559113002
upvotes: 4
mistakes:
  answer: "The vulnerability was essentially a design mistake that gave nested modals\nthe
    privledge to bypass the Same Origin Policy. It is interesting that the\ntwo methods
    used to mitigate this vulnerability were in the repository for \nsix years before
    it was discovered. \n\nIt's possible that there was a similar vulnerability that
    was found in the \npast. It's also possible that similar functionality was implemented
    in a different\nsystem by a developer who may have had more knowledge or awareness
    of security.\n\nIt appears that trust boundaries were drawn, but not around all
    of the components\nthat may cross it. Proper analysis of the architecture is really
    the only mitigation\nagainst this kind of vulnerability. Since this vulnerability
    was found by someone\noutside the Chromium team, it is unclear if this has been
    done.\n\nThe lesson to be learned here is that discovery of a vulnerability such
    as this warrents\nan audit of existing subsystems that may also be susceptible
    the same vulnerability. This could \nbe done with a fuzzer or by manual inspection
    of the code and design.\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: '2016-03-02'
subsystem:
  name: pepper
  answer: Based on the issue report.
  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: '2015-12-14'
  answer: |
    It is not clear how this vulnerability was discoverd, if by manual inspection
    or by fuzzer; however, it was reproduced manually using an exploit provided in
    the issue report.
  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: 
description: "The vulnerability was in Google's Flash Player module, *Pepper*, in
  the way the\nFlash Message Modal (basically windowless pop-ups) handled nested modals.\n\nThe
  implementation did not suspend script callbacks or resource loads inside\nthe nested
  modal box. As a result, cross-origin documents could be loaded from\nan arbitrary
  Javascript execution point. This vulnerability bypasses the Same\nOrigin Policy
  and could be used to cause denial of service, loss of sensitive \ninformation, and
  execution of arbitrary code.\n"
unit_tested:
  fix: true
  code: true
  answer: |
    It is clear from the code that there were unit tests in place for this
    module and that additional test cases were added to verify the fix.
  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: 
    name: 
  - 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: 
  commits:
  - note: "The code eventually used to fix this vulnerability was introduced six years
      \nprior to the discovery of this vulnerability and two years after the vulnerable\ncode
      was introduced into the repository.\n\nAt this point it seems like the developers
      were aware of the possible problems\nwith arbitrary script execution within
      modal loops.\n"
    commit: f7624d0002bfdc2d67f4d28b680426d0bbc1535d
  - note: "The task handler system that is used to run recursive message modal loops
      was \nupdated to make nested message loops safer. The developers even added
      warnings \nin the comments that, in general, nestable message loops should be
      avoided because\nthey are dangerous and difficult to get right.\n\nIn this commit
      the vulnerable Flash Message Loop was updated to use the updated\ntask handler.\n"
    commit: b5717a4f9f66283a9fe04ae1f9a3a89920d5b6b0
  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.