CVE-2013-6627

CVE: CVE-2013-6627
CWE:
- 119
bugs:
- 299892
repo: https://src.chromium.org/viewvc/chrome/trunk/src/
vccs:
- note: 
  commit: 
fixes:
- note: ''
  commit: 9519554063b33251506876e9bfa8072e29a95a57
bounty:
  date: '2013-10-22'
  amount: 4000.0
  references:
  - http://chromereleases.googleblog.com/2013/11/stable-channel-update.html
  - https://bugs.chromium.org/p/chromium/issues/detail?id=299892
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: |
      The main cause of this buffer issue was the incorrect parsing of 1xx HTTP
      response codes which were sent from a malicious web server. The developers
      always assumed certain things about the buffer which also contributed to
      this 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:
- 33053003
- 25312002
upvotes: 10
mistakes:
  answer: |
    The vulnerability appears to mainly stem from design mistakes. This is
    evident because the code shows that the developers did not know that 1xx
    HTTP response status codes are different from the other classes of status
    codes. Also, the developers made a lot of assumptions without considering
    whether the code written actually fit their assumptions.

    The vulnerability shows miscommunication issues regarding the
    assumptions made (which influence which fix option was used). There also
    seems to be little communication between people on the team. I believe this
    based on the defensiveness in the bug thread and the fact that a developer
    moved around code without knowing how that code actually works.

    Overall, it appears that while the vulnerability was caused by a relatively
    small number of lines of code, the vulnerability was merely the symptom of
    larger issues including design mistakes, assumptions, and miscommunications.
  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: '2013-11-13'
subsystem:
  name:
  - internals
  - network
  answer: |
    Subsystems listed in the Issue 299892 bug thread in the chromium issue
    tracker
  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: '2013-09-27'
  answer: |
    It is unclear how this vulnerability was initially discovered. However, the
    dicoverer wrote a very detailed vulnerability report that included: a zip
    file containing an example implementation of a web server that demonstrates
    the vulnerability, and 2 patch files containing possible fixes.
  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: |
  An attack can access information beyond the length of a buffer storing HTTP
  response headers by having web server use pecially crafted informational
  HTTP response codes (1xx). These HTTP response codes are incorrectly processed
  and are nott removed from the front of the buffer. Other parts of the code
  always assumes that the current HTTP response being parsed is at the front of
  the buffer and the incorrectly processed 1xx response code produces a length
  longer than the buffer of the responses. The attacker can use this to read the
  main process' memory and change its execution.
unit_tested:
  fix: true
  code: true
  answer: |
    From looking at the fix code. It is obvious that the orginal code was
    unit tested and a new test was added specially for this 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: One event prior to the discovery found in issue tracker
  events:
  - date: 
    name: |
      A developer "touched" the code by moving it around. They did not know
      that there was anything wrong with the code. He defended himself in the
      issue thread because he believed he was being blamed for writing the
      defective code.(See issue thread https://bugs.chromium.org/p/chromium/issues/detail?id=299892)
  - 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 only one commit which was the fix. The fix involved adding a check
    for the buffer offset, changing the reading of the buffer from the buffer
    offset to just the first item in the buffer, changing the way response body
    sizes were calculated (with 1xx response always having a length of 0), and
    the associated new unit test.
  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.