CVE-2016-8743

CVE: CVE-2016-8743
CWE: 156
ipc:
  note: 
  answer: 
  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. Explain your answer
bugs: []
i18n:
  note: 
  answer: 
  instructions: |
    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.
repo: 
vccs:
- note: |-
    Introduce Apache baseline, including read_request_line method without strict whitespace validation.

    Formerly 5430f8800f5fffd57e7421dee0ac9de8ca4f9573 before HTTPD rewrote Git history.
  commit: 6f96ad52275b5b35226cdb2ce66b3832e9dfb605
fixes:
- note: |-
    Allow whitespace unconditionally in one specific location.

    Formerly b1447ec5f9c0369e21a06a42b450a886552dffb8 before HTTPD rewrote Git history.
  commit: 5b2748e303435559ac7d90c5fdaef545647c9e54
- note: |-
    Ensures bad whitespace is never permitted.

    Formerly eb99a690dcf43cf1254a8cf21c541d835a8ef3d5 before HTTPD rewrote Git history.
  commit: b06490c39c8ea0d4adef20704a8a3f3421a63759
- note: |-
    Introduce Strict & Unsafe whitespace modes and ensure Strict is default.

    Formerly e62dee76dc7d7104acada86fb7bebe8996b77fcd before HTTPD rewrote Git history.
  commit: 6cae6f2487a1cf2f41c712a126e1b4bb370cbd57
- note: |-
    Introduce Strict & Lenient (renamed to Unsafe) whitespace modes, but keep Lenient default.

    Formerly f053104613a4c9e8813fc91cc1e136cd6c1b2612 before HTTPD rewrote Git history.
  commit: 8d77efe21eb7a1796521a3212109036d775a61f6
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: |
      Because whitespace may often be introduced into requests without humans noticing,
      these complex whitespace patterns need not be malicious. They need sanitized nevertheless.
    applies: true
  distrust_input:
    note: |
      This vulnerability involves input that includes unusual and possibly malicious
      whitespace patterns in requests.
    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: []
upvotes: 
CWE_note: 
mistakes:
  answer: |
    This issue is primarily a design flaw in the original request parser.
    Rather than simply ignore any combination of whitespace, it should have
    been validating that specific required and common patterns were used so that
    collaborative components not controlled by the project could accept this input
    without issue.

    The vulnerability is easily fixed by validating that the input meets the whitespace
    criteria and in some cases sanitizing it for other components/servers. That is essentially
    what was done in this case, except that configuration modes were added so that
    strict validation takes place by default, but an unsafe mode preserves the old behavior.

    Between the time the parser was originally introduced to the repository in 1999 and when
    the fix was applied in 2016, the parsing logic remained largely the same, with the exception
    of moving it back and forth between a few modules. (This is why no interesting commits are listed).
  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.
nickname: 
reported: 
announced: 2017-07-27 2016-12-20
published: 
subsystem:
  name: server
  answer: |
    The mistake takes place in the server protocol subsystem. More specifically,
    it takes place during request parsing, at the fundamental level of reading
    a single line of request input (read_request_line).
  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.
discovered:
  date: '2016-02-10'
  answer: |
    This issue was reported separately by David Dennerline at IBM Security's X-Force Researchers
    and Régis Leroy. The report does not indicate additional details.
  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 this part blank.
  automated: false
description: |
  Uncommon whitespace patterns are accepted in requests and included in responses.

  When the server is working with backends, proxies, or other servers that do not
  properly handle this whitespace or have special meaning for such whitespace,
  multiple responses could be generated. This can cause some backends to wrongly
  associate one response with a different request, causing cache pollution or more
  serious problems down the chain.
unit_tested:
  fix: false
  code: false
  answer: |
    The fix commits do not appear to make any changes to test files, and test
    files for this function were not found.
  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.
specification:
  answer: 
  answer_note: 
  instructions: |
    Is there mention of a violation of a specification? For example,
    an RFC specification, a protocol specification, 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.
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!)
autodiscoverable:
  answer: 
  answer_note: 
  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

    Examples for false: RFC violations, permissions issues, anything
    that requires the 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.
yaml_instructions: 
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: |-
      Revert refactor of read_request_line.

      Formerly 70188dee86bb700c271e69149bf991ed3a76ea7b before HTTPD rewrote Git history.
    commit: 761ef9ee176aef1a236f7f747ee9360acdcadeaf
  - note: |-
      Refactor of read_request_line.

      Formerly be3a35e2417013e4d7e343660c40ff7df14f183f before HTTPD rewrote Git history.
    commit: 0aece3ad6c7a67f88810e05e8032da836cb12e27
  - note: |-
      Revert move of read_request_line.

      Formerly cbfc4cad68442bf9a65345981a0e1fceceaf2ec4 before HTTPD rewrote Git history.
    commit: 4647e5f71a4b2d1d62238b9bce854a501b5477fb
  - note: |-
      Move read_request_line to different file.

      Formerly deb7ee64ad5e4dccbc2f4a5241690782df58d241 before HTTPD rewrote Git history.
    commit: 429614604301d118d5fd7231f452a7cef7c9f7b3
  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?
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.
nickname_instructions: |
  A catchy name for this vulnerability that would draw attention it. If the
  report mentions a nickname, use that. Must be under 30 characters.
  Optional.
reported_instructions: |
  What date was the vulnerability reported to the security team? Look at the
  security bulletins and bug reports. It is not necessarily the same day that the
  CVE was created.  Leave blank if no date is given.
  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 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.
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 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.