CVE-2013-2839

CVE: CVE-2013-2839
CWE:
- 704
- 399
bugs:
- 230176
repo: 
vccs:
- note: The first commit, which created the code to perform the functionality in question
    and introduced the bug.
  commit: 1c1fc178aac368450d1fb23620072ba22c55f077
- note: |
    Someone refactored this code to use a local method to convert the img into an element rather than casting it
    statically.
  commit: 93a2b89f9aee4f9e26d978d410eae04322ce8198
fixes:
- note: ''
  commit: 941926df060793ce28c4f4aa2aba45afee8c0fef
bounty:
  date: '2013-05-21 12:30:00.000000000 -04:00'
  amount: 1500.0
  references:
  - http://chromereleases.googleblog.com/2013/05/stable-channel-release.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: |
      This bug occurred because the original developer assumed that they could trust the inputted image to be of
      the type that they expected. By not validating that the input could be legally casted to a HTMLImageElement,
      this edge case was created.
    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:
- 14099005
upvotes: 9
mistakes:
  answer: |
    The mistake occurred because the developer did not properly validate his inputs, which would be a coding mistake,
    although an argument can be made that the developer may not have followed the design correctly. All user input
    should be validated to ensure that what the system receives is what it expects. Also, directly casting user input
    into another form of data is also a fairly large risk and can lead to the issues with memory. In this example, the
    casting of the illegal types into a HTMLImageElement allowed access to parts of the heap that could be manipulated
    by the user, which is highly dangerous.
  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: '2013-05-22 09:29:55.997000000 -04:00'
subsystem:
  name: v8
  answer: Obvious to see that the bug was in the V8 module from the file names.
  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: '2013-04-11'
  answer: It is not clear how this vulnerability was discovered.
  google: true
  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: |
  When a user attempts to copy and paste an image via dragging, the image is typecasted into a HTMLImageElement without
  proper checks being performed to make sure that the cast is legal. This allows illegal types of image elements,
  such as SVGS, to be casted as a HTMLImageElement.

  Right after the casting is performed, the cachedImage() method is
  called on the casted HTMLImageElement. Since the HTMLImageElement has a larger virtual table than a SVG file, the
  adjacent memory around the casted SVG is used as part of the virtual table.

  These values in memory could be
  controlled if heap manipulation was performed before triggering the bug, allowing for arbitrary code execution.
unit_tested:
  fix: true
  code: false
  answer: |
    There were no automated unit tests for the initial commit of this functionality, which introduced the bug.
    However, once the bug was discovered, a test was introduced that tested the functionality.
  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: None in particular.
  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: 'There was one interesting commit in which an individual changed the suspect
    line of code but did not fix the bug.

    '
  commits:
  - note: |
      The developer changed the line of code from using a static cast of the node to an element into using a method
      to cast the node, but did not notice the vulnerability.
    commit: 93a2b89f9aee4f9e26d978d410eae04322ce8198
  - 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.