CVE-2016-7549

CVE: CVE-2016-7549
CWE:
- 664
bugs:
- 445054
- 556351
repo: 
vccs:
- note: |
    The vulnerability does not have a commit that introduced it, it was poor design
    of the function and a lack of testing that caused that bug. The commits
    closest to dealing with the vulnerability are da9a32b9e282c and cce56cd.
    From the looks of commit da9a32b9e282c, a todo was set up to check one
    variable of the current objects state. Commit cce56cd
    added a check on the current state, but only checked the one variable of the state.
    The fix for this bug would later check the another existing variable of the
    state of the object (render_frame_created_).
  commit: da9a32b9e282c1653bb6b5c1b8c89a1970905f21
fixes:
- note: ''
  commit: b78ba88705cb799426204d2ffd6b8cc558d0d3b7
- note: ''
  commit: cfc11a5bf3023957667c65a76b726978f7a5a4e5
bounty:
  date: 
  amount: 
  references: []
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: 
    applies: 
  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: 
  distrustful_decomposition:
    note: |
      'IPC between processes should always be validated, this validation may
      include checking a process is still active'
    applies: true
reviews:
- 1027383002
- 1534933002
- 812513004
- 877473003
upvotes: 
mistakes:
  answer: |
    This vulnerability stemmed from design flaw that assumed object state.
    The reason for this design flaw can be summed up by a comment from one of
    the developers.

      'I see This frame being destroyed then sent a message,
      I thought that should never happen'.

    This type of assuming will lead to oversights and design flaws
    such as this one. The mitigation for the CWE is 'Use Static analysis tools
    to check for unreleased resources'. This sums this fix introduced for this
    vulnerability, checking the state of the object instead of assuming it.
  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'
subsystem:
  name: renderer
  answer: The mistake was in the subsystems that render the frames and widgets for
    the browser
  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: '2015-11-15'
  answer: |
    issue (556351) that the bug originally stemmed from was a report generated
    by a a google fuzzer called 'ClusterFuzz',
    It had found and reported a crash, developers then tested and found the issue
    to be the vulnerability.
  google: true
  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: true
description: |
  The reciever of an IPC message was never validated, meaning the messages could
  be sent out to null, invalid or 'dead' processes. This created an opportunity
  for denial of service attacks as well as an opening for arbitrary code execution.
unit_tested:
  fix: true
  code: true
  answer: |
    There were unit tests in place for the surrounidng code, but none that
    tested for the specific vulnerability scenario. The existing unit tests
    have been improved to set the rendering state of object, but have still
    not been modified to test for the scenario that this vulnerability causes.
    This may be because the fix for the vulnerability was simple, and it has
    been decided that further testing is not needed.
  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 fix for this bug also involved removing code for a bug that had went unfixed
    for over a year before being closed. functionality had been disabled due to the
    bug, but its reintroduction was included in this commit.
    (https://bugs.chromium.org/p/chromium/issues/detail?id=445054)
  events:
  - date: '2014-12-24'
    name: reintroduction of functionality taken out due to MAC bug
  - 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: |
    While the vulnerability did not nessecarily have a vcc, it did have interesting
    commits where the state of the object was partially checked. This along with
    the fact that the state of the object was available, makes it clear that the
    designers of the system did not think of the possiblity of this occuring.
  commits:
  - note: adds comment to check variable of state (is_swapped())
    commit: da9a32b9e282c1653bb6b5c1b8c89a1970905f21
  - note: checks commented variable, does not add check for if object is rendered
    commit: cce56cd951f6685a0120db63418aa7e6d3df28f2
  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.