CVE-2014-7929

CVE: CVE-2014-7929
CWE:
- 416
- 17
bugs:
- 443115
repo: 
vccs:
- note: |
    There is a lot of unit testing; however, the testing that exists
    does not cover the vulnerability.
  commit: 98b6f3647aadfed61bfdb79c94bcf17666bf197a
fixes:
- note: |
    This fix commit only changes the comment on how the document pointer obtain
    the document when the document pointer is not valid based on conditions.
  commit: 3236511f3903f30855f2f9f81193cf94e8a19392
- note: |
    The fix commit includes an if statement to check if the document pointer
    is still valid otherwise fix by updating the document pointer from
    the document reference.
  commit: 6b51dbf1788c15785cb3e0febaab1593dc9fec5a
bounty:
  date: '2015-01-21 15:11:00.000000000 -05:00'
  amount: 2000.0
  references:
  - http://chromereleases.googleblog.com/2015/01/stable-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: |
      Seems that the part of the code for this vulnerability is complex based on
      the bug and function. The code has to move the running script (javascript) from
      an old document to a new document. The code is also involved in with a frame
      detached document function; therefore, Chrome has to manage all contents and
      scripts across the documents.
    applies: true
  distrust_input:
    note: |
      Chrome did not check the document pointer to see if the pointer is valid
      while moving the script from an old document to a new document might allow
      an attacker to attack Chrome after crash with the use after free vulnerability.
    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:
- 827233002
- 809323002
- 798493005
upvotes: 2
mistakes:
  answer: |
    The person who was working on adding the feature by moving a running script across
    documents did not check the use after free vulnerability case. It seems the original
    code unit did not review all cases at the VCC. He/she did apply unit tests in the VCC
    for some cases but not all. The VCC was focusing on moving pending async script loader
    to the new document introduced the use after free vulnerability with the document
    pointer.
  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: '2015-01-22 17:59:10.867000000 -05:00'
subsystem:
  name:
  - blink
  - dom
  answer: Based directory path and CVE.
  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: Dec-17-2014
  answer: |
    Seems the vulnerability is a part of complex inputs because there were some issues
    previous in the same code file. People find a lot of bugs in the file where the
    vulnerability is.
  google: false
  contest: true
  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: |
  Use after free vulnerability occurs in moving a script from old document to
  new document function. The function can cause a denial of service or an impact.
  When a user moves an old document to a new document, then Chrome will move the
  script between the old document and the new document. Chrome did not check if
  the script is allocated or not will cause a crash or an attacker can add input
  to overwrite memory.
unit_tested:
  fix: true
  code: true
  answer: |
    The original unit test did not test the vulnerability, but it tested
    other functions. The original unit test does not check if the document
    pointer is still valid when moving a script across documents.
  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: No major events.
  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 VCC was focusing on another issue; however, this brings the vulnerability
      for use after free. The VCC was for transferring a script from old document to
      a new document. The VCC did not include a unit test for the document pointer to
      check if the pointer is valid while moving the script to the document pointer.
    commit: 98b6f3647aadfed61bfdb79c94bcf17666bf197a
  - 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.