CVE-2014-1733

CVE: CVE-2014-1733
CWE:
- 595
- 20
bugs:
- 351103
repo: 
vccs:
- note: VCC was the same commit where the compare function was implemented.
  commit: 772c04797682f3936e8323dbd04c311268ee01fe
fixes:
- note: Fix is done by calling the PointerCompare method on the children of the original
    blocks to ensure that they are the same.
  commit: f6205c925db9508cb21c98cf7488eb785e08ff0b
bounty:
  date: '2014-04-24 13:46:00.000000000 -04:00'
  amount: 500.0
  references:
  - http://chromereleases.googleblog.com/2014/04/stable-channel-update_24.html
lessons:
  yagni:
    note: |
      The vulnerability came into play because the author wanted to reduce the time it took to make a comparison as
      well as minimize the code written for comparison to maintain simplicity. By not accounting for the edge case,
      where the "next" conditions could be different the author accidentally created this bug.
    applies: true
  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 vulnerability involves parsing blocks of code and pointer logic and arithmatic, which is difficult to work
      with.
    applies: true
  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: 
reviews:
- 231783003
- 215173002
upvotes: 3
mistakes:
  answer: |
    The biggest mistake made in causing this vulnerability is that the developer in question did not think of all the
    edge cases. As the developer did not think that they would need to compare the 'next' blocks of code to be
    executed, it created this edge case where the code allowed an illegal merge because it did not look deeply enough.
    I would argue that this is a coding mistake, although this could have been caught at multiple levels. Better
    requirements, testing, or design would have potentially caught this issue, but it ultimately fell through to the
    developer to ensure that the case was accounted for, which they failed to do.
  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: '2014-04-24 06:55:05.543000000 -04:00'
subsystem:
  name: Linux Sandbox
  answer: Based on the results of the original report and bug report.
  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: '2014-03-10'
  answer: |
    The bug was discovered when another user attempted to integrate Chromium's seccomp-bpf codegen module into another
    project. They discovered this bug when their program crashed on compilation due to two blocks being illegally
    merged after running the merging functionality of the module.
  google: false
  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: |
  The bug was in Chromium's Sandbox in the way they detected and merge two blocks of code via PointerCompare and
  TailMerge.

  When executing a compare and a merge, the code does not properly account for the "next" pointer (the
  next lines of code to execute after the blocks have finished executing) if the two blocks are not JMP (jump) or RET
  (return) instructions.

  This creates an edge case where two blocks of code could be identical except that their 'next' pointer is
  different, but the two blocks get merged anyways. This merge can introduce a cycle into the program and
  can cause crashes during compilation. Worst case scenario, this can lead to illegal system calls via an attached
  BPF program.
unit_tested:
  fix: true
  code: true
  answer: 'Several tests were added for testing this edge case after fixing the vulnerability.

    '
  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 are seen.

    '
  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: Not many significant changes occurred to the sections of the code in question
    in between the VCCs and Fix. The majority of the changes to the file were changes
    to other parts of the code, although interestingly enough there were several reverted
    commits due to incorrectly implemented solutions.
  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.