CVE-2013-4263

CVE: CVE-2013-4263
CWE: 119
ipc:
  note: No IPC occurred.
  answer: false
  question: |
    Did the feature that this vulnerability affected use inter-process
    communication? IPC includes OS signals, pipes, stdin/stdout, message
    passing, and clipboard. Writing to files that another program in this
    software system reads is another form of IPC.

    Answer should be boolean.
CVSS: AV:N/AC:L/Au:N/C:P/I:P/A:P
bugs: []
i18n:
  note: "There is no mention of internationalization and no obvious \napplicability
    in the code itself.\n"
  answer: false
  question: |
    Was the feature impacted by this vulnerability about internationalization
    (i18n)? An internationalization feature is one that enables people from all
    over the world to use the system. This includes translations, locales,
    typography, unicode, or various other features.

    Answer should be boolean. Write a note about how you came to the conclusions
    you did.
vccs:
- note: 'First instance of the vulnerability within the codebase.

    '
  commit: 3c940173c0ada2d76c83da80aae816f720f3cb3a
- note: |
    A new instance of a stride value being accessed without
    checking if it exists first.
  commit: 172505b8bc361e4b08c75baf2d4d94e6c2ac94b9
- note: |
    A new instance of a stride value being accessed without
    checking if it exists first.
  commit: 0ab9362fcb77c2d442fa20afcc2f1d9151228f06
- note: |
    A new instance of a stride value being accessed without
    checking if it exists first.
  commit: 7a92ec93c6507bd3dea4563ec7a0e3679034fc57
- note: |
    Several new instance of stride values being accessed without
    checking if they exists first.
  commit: 6b61920ab76dc6d85ef462909951923935dd643f
- note: |
    A new instance of a stride value being accessed without
    checking if it exists first.
  commit: aa0c515a3cfaa4718a7ac7f2b3ea386daf05c019
- note: |
    A new instance of a stride value being accessed without
    checking if it exists first.
  commit: dd2793c880ea72c9aacda8245596694d9b4f378c
- note: |
    A new instance of a stride value being accessed without
    checking if it exists first.
  commit: d5f187fd3355ec6d4922d8479930c10d1b6f9ebf
- note: |
    A new instance of a stride value being accessed without
    checking if it exists first.
  commit: 2701f6cc6aca624e6d26f1bd3bd6190b8024ea6b
- note: |
    A new instance of a stride value being accessed without
    checking if it exists first.
  commit: a1e171dfee17a9dcc7c5907b16d5c1a2748bfe73
- note: |
    A new instance of a stride value being accessed without
    checking if it exists first.
  commit: 31d8467d82d41d9a6720d4b4bd7bf60eab547d5e
fixes:
- note: "Before accessing the stride of a given plane, there is now a condition \nthat
    first checks for the presence of a valid stride. The fix is\napplied multiple
    times in the code base to address the vulnerability.\n"
  commit: e43a0a232dbf6d3c161823c2e07c52e76227a1bc
bounty:
  amt: 
  url: 
  announced: 
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: "The video file is a very complex input. A processed frame\nfrom the video
      is affected by many pieces of code and many\nconditions/states. There's no way
      to know for sure if the \nneeded data is present unless it's explicitly verified.\n"
    applies: true
  distrust_input:
    note: "FFmpeg accepts many different types of video files, so\nthere are many
      ways in which an attacker could craft a file\nto create an exploit. It is not
      safe to assume that the given\naudio file will conform to the expected states
      and behavior.\nTo prevent an exploit, the only certain way to verify a proper
      \nstate is to check for it explicitly.\n"
    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: 
upvotes: 4
CWE_note: 
lifetime:
  answer: "The vulnerability was first introduced on May 7, 2010 with the\naddition
    of the PAD filter. Until the fix occurred on August 3, 2013, \nthe same code appeared
    in 10 new files. Once the code had been \nintroduced to a file, it was not altered
    except for variable name \nchanges. All instances of the vulnerability were fixed
    in the same commit.\n"
  question: |
    We consider the "lifetime" of this vulnerability to be from the earliest
    VCC to the latest fix.

    How would you characterize the development of this vulnerable code during
    its lifetime? Many new features? Neglected? One developer?
    Massive refactoring? Changing big dependencies?
    Changing architectures or language?


    What about the time period for the project itself?
    Did it undergo big changes during this time?

    Look at:
      * the commit messages between the two, using a command like
          git log --stat abc..def -- your/file.c
          (where a)
      * the changelog between the two
mistakes:
  answer: "The vulnerable code does check that there is a value for every plane, but\nit
    does not check if the associated stride value exists. This is a \ndangeous assumption,
    because any bug or exploit that results in that value\nbeing absent now causes
    an application crash or worse. Introducing a check\non the stride value array
    is a simple case of defensive programming that \nwas overlooked when the code
    was written.\nThe vulnerability was created once, then the code was most likely
    copied\nand pasted as new files with similar functionality were added. The code
    \nwas probably not thoroughly inspected or considered before it was copied. \nAs
    a result, the fix had to be applied in multiple places once the \nvulnerability
    was found. The fix explicitly checks that each stride value \nexists, so there
    should be no way for an out-of-bounds access to occur now.\n"
  question: |
    In your opinion, after all of this research, what mistakes were made that
    led to this vulnerability? Design mistakes? Maintainability? Requirements?
    Miscommunications? Lack of testing? Lack of understanding? Lack of
    specifications? Working alone?

    An answer like "it was just a coding mistake" is not thoughtful enough.
    If it's such an easy mistake to make, how was it missed?

    Also, 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.
nickname: 
subsystem:
  name: avfilter
  answer: |
    The commit message of the fix begins with "avfilter", and the file exists
    in the "libavfilter" directory.
  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.

    In FFmpeg, the Component field is useful here. Often people will say
      "undetermined" - do more homework than them and make a judgement call if
      you can.

    Note: a filepath is NOT a subsystem - that's too granular.

    A non-exhaustive examples for ffmpeg are:
      * avcodec
      * avdevice
      * avfilter
      * avformat
      * avutil
      * build system
      * documentation
      * fate
      * ffplay
      * ffprobe
      * postproc
      * swresample
      * swscale
      * tools
      * trac
      * website

    If this involves fixing multiple subsystems, you can make this an array.

    In 'answer', explain how you arrived at this determination.
discovered:
  answer: "I could not find info about how this vulnerability was discovered.\nI performed
    multiple searches on the bug tracker (function names, \ncode keywords, bugs related
    to filters and heap writes). The commit \nmessage and CVE page (description and
    links) were also not helpful. \nI looked for IRC conversations or other logs,
    but found none.\n"
  contest: false
  question: |
    How was this vulnerability discovered?

    Find any relevant bug reports or mailing list conversations read the
    conversation to find out how this was
    originally found. Answer in longform below in "answer".

    If it's clear that the vulenrability was discovered by a
    contest, fill in the name of the contest in "answer".

    If it's clear that it was found by a developer of the project itself,
    e.g. from the email address or a previous committer.

    The automated, contest, and developer flags can be true, false, or nil.

    If there is no evidence as to how this vulnerability was found, then please
    explain where you looked. Thus, 'answer' should always have some
    explanation.
  automated: false
  developer: false
description: In FFmpeg, colors in a video frame are encoded using "planes", which
  are sets of bits representing the colors of each pixel in the image. For a single
  frame, FFmpeg stores several planes as well as the "stride" of each plane, which
  is a number related to the width and height of the frame. An attacker may craft
  a video file wherein one of the planes may have a plane with no associated stride
  value. The code would then try to access the stride for that plane (an alement in
  an array), which does not exist (i.e. out-of-bounds). This may cause an application
  crash or other negative impact.
unit_tested:
  fix: false
  code: true
  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 code: and fix: - your answer should be boolean.

    For the code_answer below, look not only at the fix but the surrounding
    code near the fix in related directories and determine if and was there were
    unit tests involved for this subsystem. The code

    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.

    In FFmpeg, they have the FATE suite of regression tests. They are not
    "unit" tests per se, but are automated regression tests. If the fix for the
    vulnerability involved adding or updating a FATE suite, then make fix: true.
  fix_answer: No unit tests were modified as part of the fix commit.
  code_answer: "There are tests in \"filter-video.mak\" that use the filters with
    vulnerable \ncode (e.g. boxblur from \"vf_boxblur.c\").\n"
reported_date: 
specification:
  answer: false
  answer_note: |
    There are no mentions of a specification violation in any of the
    available resources.
  instructions: |
    Is there mention of a violation of a specification? For example,
    an RFC specification, a protocol specification, codec spec, or a requirements
    specification.

    Be sure to check all artifacts for this: bug report, security
    advisory, commit message, etc.

    The answer field should be boolean. In answer_note, please explain
    why you come to that conclusion.
announced_date: 2013-11-23T17:55Z
curation_level: 1.0
published_date: 2013-11-23T17:55Z
CWE_instructions: |
  Please go to http://cwe.mitre.org and find the most specific, appropriate CWE
  entry that describes your vulnerability. We recommend going to
  https://cwe.mitre.org/data/definitions/699.html for the Software Development
  view of the vulnerabilities. We also recommend the tool
  http://www.cwevis.org/viz to help see how the classifications work.

  If you have anything to note about why you classified it this way, write
  something in CWE_note. This field is optional.

  Just the number here is fine. No need for name or CWE prefix. If more than one
  apply here, then choose the best one and mention the others in CWE_note.
autodiscoverable:
  answer: false
  answer_note: |
    Crafting a video file to exploit the vulnerability would require
    too much domain knowledge.
  instructions: |
    Is it plausible that a fully automated tool could have discovered
    this? These are tools that require little knowledge of the domain,
     e.g. automatic static analysis, compiler warnings, fuzzers.

    Examples for true answers: SQL injection, XSS, buffer overflow,
    use-after-free

    Examples for false: specification violations, permissions issues, anything
    that would require a tool to be "aware" of the project's
    domain-specific requirements.

    The answer field should be boolean. In answer_note, please explain
    why you come to that conclusion.
bugs_instructions: |
  Are there any bug reports that trace to this vulnerability?

  Sometimes a commit message will mention a bug, or the security page on FFmpeg.
  Sometimes you need to search bug database, which is here:
      https://trac.ffmpeg.org
yaml_instructions: |
  ===YAML Primer===
  This is a dictionary data structure, akin to JSON.
  Everything before a colon is a key, and the values here are usually strings

  For one-line strings, you can just use quotes after the colon

  For multi-line strings, as we do for our instructions, you put a | and then
  indent by two spaces.

  For readability, we hard-wrap multi-line strings at 80 characters. This is
  not absolutely required, but appreciated.
  === End YAML Primer===
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:
  commits:
  - note: Name change without fixing the vulnerability
    commit: 2a06bc10e7cb489c13613ac15c48b274013641d3
  - note: Name change without fixing the vulnerability
    commit: eb7e7e82e17b0353fbcfdee616cfe89e525eae53
  - note: Name change without fixing the vulnerability
    commit: bff576c779476c5325edb2e90828051138416759
  - note: Conditions are rearranges without fixing the vulnerability
    commit: 9138f6da4a3ee0d11947b8593db6b6b05e53fbae
  - note: Name change without fixing the vulnerability
    commit: 250b122e3ab12baeef4fb65c4d76df4fc506b899
  - note: Name change without fixing the vulnerability
    commit: 384641468b60f40e9bf9b1f887abd5e3c3a9be1c
  - note: Name change without fixing the vulnerability
    commit: e67fdbffe588e6b5bc787457da9d5941657a0029
  question: |
    Optional: 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?

    This is a catch-all for any interesting commit you find.
    Example of interesting commits:
      * Giant refactors
      * Changing an API or big dependency
      * A change that looks really sketchy
      * Commits where a developer mentions security in their message or comments
curated_instructions: |
  If you are manually editing this file, then you are "curating" it.
  This will enable additional integrity checks on this file to make sure you
  fill everything out properly.

  IMPORTANT: If you are a student, we cannot accept your work as finished unless
  curation_level is properly set.

  The latest curation level is 1.0.
  If you are curating this vulnerability, set it to the latest curation level.
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.
nickname_instructions: |
  A catchy name for this vulnerability that would draw attention it. If the
  report mentions a nickname, e.g. "Heartbleed", use that. Or come up with one!

  Must be under 30 characters. Optional. Be appropriate.
reported_instructions: |
  What date was the vulnerability reported to the security team? Look at the
  security bulletins, bug reports, commit messages of the fix.

  Reported date is likely the same as announced and published. Leave blank if
  you can't find it out.

  Please enter your date in YYYY-MM-DD format.
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 of this for FFmpeg are their version numbers traced to tags:

    https://ffmpeg.org/security.html



  Please enter your date in YYYY-MM-DD format.
fixes_vcc_instructions: |
  Please put the commit hash in "commit" field below (see my example in
  CVE-2011-3092.yml).

  Fixes and VCCs follow the same format - they are arrays of hashes.

  The notes field is optional - place anything that clarifies things or you
  find interesting in there.
published_instructions: |
  Is there a published fix or patch date for this vulnerability?
  Please enter your date in YYYY-MM-DD 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 project-specific
  stuff. Remove references to versions, specific filenames, and other jargon
  that outsiders to this project would not understand. Technology like "regular
  expressions" is fine, and security phrases like "invalid write" are fine to
  keep too.

  Your target audience is people just like you before you took any course in
  security