angler-fishThe Vulnerability History Project

CVE-2015-1284

This vulnerability is caused by the blink functionality of Chrome not checking for exceeding the maximum frame amount after the amount has been set. This allows an external attacker to create a denial of service attack by creating more than 1024 frames which reads from memory after being freed.


The mistake that lead to this vulnerability was checking the value in the input then storing the value in the input, instead of the other way around. This allowed an attacker to create a script with more than 1024 frames which is more than the system allows for and would try and access memory after it had been freed and crash. This creates a denial of service. This is a coding mistake which should be caught with code review. The fix looks proper because it adds a check with security consequences rather than just checking the input. The potential mitigations for this CWE are to choose a language that provides automatic memory management, which isn't really an option in this case. The other mitigation is to set pointers to NULL after freeing them, however, the fault that results from this is part of the vulnerability.
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CVE: CVE-2015-1284
CWE:
- 416
- 20
bugs:
- 493243
repo: 
vccs:
- note: ''
  commit: ee2b344b0b5773d396f7aa7deca9200e96c940ec
fixes:
- note: ''
  commit: 02ab4913c82188af2c7e440742a11d5231dbaa0e
bounty:
  date: '2015-07-21 14:00:00.000000000 -04:00'
  amount: 2000.0
  references:
  - http://chromereleases.googleblog.com/2015/07/stable-channel-update_21.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: they were checking input too early to detect a problem with input
    applies: true
  distrust_input:
    note: a lack of input checking allowed for having more frames than is allowed
    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:
- 1180603002
- 1233453006
upvotes: 5
mistakes:
  answer: |
    The mistake that lead to this vulnerability was checking the value in the
    input then storing the value in the input, instead of the other way around.
    This allowed an attacker to create a script with more than 1024 frames which
    is more than the system allows for and would try and access memory after it
    had been freed and crash. This creates a denial of service. This is a coding
    mistake which should be caught with code review. The fix looks proper because
    it adds a check with security consequences rather than just checking the input.

    The potential mitigations for this CWE are to choose a language that provides
    automatic memory management, which isn't really an option in this case. The
    other mitigation is to set pointers to NULL after freeing them, however, the
    fault that results from this is part of the vulnerability.
  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: '2015-07-22 20:59:13.587000000 -04:00'
subsystem:
  name: Blink
  answer: Comes from CVE page.
  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: '2015-05-28'
  answer: 'It''s unclear how this vulnerability was discovered

    '
  google: false
  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: false
description: |
  This vulnerability is caused by the blink functionality of Chrome not checking
  for exceeding the maximum frame amount after the amount has been set. This allows
  an external attacker to create a denial of service attack by creating more than
  1024 frames which reads from memory after being freed.
unit_tested:
  fix: true
  code: true
  answer: 
  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: 0
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: 
    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.

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