CVE-2016-2162

aka Language Switch XSS

CVE: CVE-2016-2162
CWE: 79
bugs: []
vccs:
- note: |
    It appears that this vulnerability has been around a long time, as the
    vulnerable code exists back to when the file first exists in the project
    when moved from xwork2. This is the first commit where the file exists in
    the repo, and the code is still present.
  commit: 0c543aef318341ca9bd482e15f1637497b8a4dfd
- note: Initial import of webwork
  commit: c01d3a92db7f71f751a0522912d24bcf4a94a1b0
fixes:
- note: |
    Here, the developer added logic to automatically set the Locale object
    built by the interceptor to the default locale for the system if the built
    locale was invalid. Before this commit, this check was not made and the
    locale built from the user's string was passed along regardless if it was
    a valid locale, as Java locales do not perform syntax checks by default.
  commit: 37842193ab33b7655c78a2d2c305f2e0a0e50355
- note: Allows I18N to work
  commit: f65e38bb815e98f65cb4ee987aba4ca360b408dd
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: 
    applies: 
  distrust_input:
    note: |
      Any parameters that can be modified by a user should be sanitized, and
      before the fix the I18NInterceptor allowed for unsanitized input to be
      taken from the user.
    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: 
mistakes:
  answer: |
    This seems like a design issue, as the developer did not account for the
    method contracts of Java's Locale library. Since Locale doesn't perform
    validation automatically, and the developers also did not do so themselves,
    the user input was left unchecked and carried through the rest of the
    program. This led any developer using Struts vulnerable to XSS if they
    access the Locale object directly for UI code.
  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 in the software
    engineering industry would find interesting.
nickname: Language Switch XSS
reported: '2016-03-11'
announced: '2016-03-11'
subsystem:
  name: 
  answer: interceptor
  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: 
  answer: |
    Found by Paolo Perliti. I looked through every link from the CVE tracker,
    and also searched for the reporter, the CVE, and for any timeline associated
    with it. Not much came up that was not already on the initial CVE page
    (or linked pages).
  apache: 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 Apache
    employee (you can tell from their email address). If it's clear that the
    vulnerability was discovered by a contest, fill in the name there.
    The "automated" flag can be true, false, or nil.
    The "apache" 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: 
description: |
  The Apache Struts framework uses I18NInterceptor to allow users and developers
  to switch language used in the framework and an application built on top of
  it. The problem is that the interceptor doesn't perform any validation of the
  user input while accepting arbitrary strings which can be used by a developer
  to display language selected by the user. However, the framework doesn't
  expose the value directly in UI. This means that the vulnerability is only
  exploitable if the developer explicitly puts the string from the Locale object
  onto the page.
unit_tested:
  fix: true
  code: true
  answer: |
    I18NInterceptor was unit tested both prior to and after the fix. However, it
    does not appear that they added another test for this issue specifically.
    They did update a few tests after the fix.
  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?
    Write the reasoning behind your answer in the "answer" field.
    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. Must be just "true" or "false".
    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.
    Must be just "true" or "false".
future_fixes:
- note: 
  commit: 
curation_level: 1
previous_fixes:
- note: 
  commit: 
- note: 
  commit: 
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!)
security_bulletin: S2-030
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 are no interesting commits that pertain to the file changed in the fix
    for this vulnerability. This is because the file only changed after the
    initial commit that allowed the vulnerability to occur in the fix commit
    itself.
  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: |
  Students: when initially writing this, ignore this upvotes number.
  Once this work is being reviewed, 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: |
  Nickname is optional. Provide a useful, professional, and catchy nickname for
  this vulnerability. Ideally fewer than 30 characters. This will be shown
  alongside its CVE to make it more easily distinguished from the rest.
reported_instructions: |
  Was there a date that this vulnerability was reported to the team? You can
  find this in changelogs, blogs, bug reports, or perhaps the CVE data.
  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 data.
  Please enter your date in YYYY-MM-DD format.
fixes_vcc_instructions: |
  Please put the SVN commit number in "commit" below, and any notes about how this
  was discovered in the "note" field.
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 Struts-specific
  stuff. Remove references to versions, specific filenames, and other jargon
  that outsiders to Struts would not understand. Technology like "regular
  expressions" is fine, and security phrases like "invalid write" are fine to
  keep too.
incomplete_fix_instructions: |
  Did the above "fixes" actually fix the vulnerability?
  Please list any fixes for the same issue before and after
  this CVE below.