angler-fishThe Vulnerability History Project

CVE-2003-0020

Certain terminals are susceptible to exploits in the form of harmful inputs. Take, for example, escape sequences. An escape sequence starts with the ASCII escape character and is followed by some arguments. This particular vulnerability was caused by a failure to filter escape sequences out of the terminal when outputting error logs. Attackers were able to intentionally inject escape sequences into terminals, which caused certain malicious behavior.


This vulnerability was caused by code written decades ago. In those years, software vulnerabilities were not as well known as they are today. It's easy to imagine that the original author of the code was simply unaware of the possibility of escape sequence injection through error logs. The most popular mitigation for this type of vulnerability is input validation. The recommended mitigation for CWE-150 is specifically whitelist input validation. However, the author who wrote the fix for this vulnerability chose to implement code more akin to a blacklist, rather than a whitelist, which was explicitly not recommended as a mitigation.
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CVE: CVE-2003-0020
CWE: 150
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: |-
    Initial commit for server/log.c

    Formerly 5430f8800f5fffd57e7421dee0ac9de8ca4f9573 before HTTPD rewrote Git history.
  commit: 6f96ad52275b5b35226cdb2ce66b3832e9dfb605
- note: |-
    Pass in different parameters when ap_snprintf is called

    Formerly b8a310a5969e4ce61e40d3270369866190809ee8 before HTTPD rewrote Git history.
  commit: de46b1035ba54be2877227157ec32484c3a0045e
fixes:
- note: |-
    Added input validation, including removal of escape sequences.

    Formerly 88f261355a83c28097a18f9b15d92196ec290def before HTTPD rewrote Git history.
  commit: a7db87b9add29f7543457f53863cee4ee13d58c9
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: |
      Due to the lack of filtering in error logs, attackers could inject escape
      sequences to exploit vulnerable terminals.
    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: 4
CWE_note: 
mistakes:
  answer: |
    This vulnerability was caused by code written decades ago. In those
    years, software vulnerabilities were not as well known as they are today. It's
    easy to imagine that the original author of the code was simply unaware of the
    possibility of escape sequence injection through error logs. The most popular
    mitigation for this type of vulnerability is input validation. The recommended
    mitigation for CWE-150 is specifically whitelist input validation. However,
    the author who wrote the fix for this vulnerability chose to implement code
    more akin to a blacklist, rather than a whitelist, which was explicitly not
    recommended as a mitigation.
  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: '2003-03-18'
published: 
subsystem:
  name: loggers
  answer: log
  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: 
  answer: |
    This vulnerability has many references linked to it. However, since the
    vulnerability is as old as it is, many of those links are no longer valid.
    With the few references that were still valid, no information could be found
    regarding how the vulnerability was discovered. One reference went so far
    as to say that it is unknown who discovered the vulnerability.
  google: 
  contest: 
  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: 
description: |
  Certain terminals are susceptible to exploits in the form of harmful inputs.
  Take, for example, escape sequences. An escape sequence starts with the ASCII
  escape character and is followed by some arguments. This particular vulnerability
  was caused by a failure to filter escape sequences out of the terminal when
  outputting error logs. Attackers were able to intentionally inject escape
  sequences into terminals, which caused certain malicious behavior.
unit_tested:
  fix: false
  code: false
  answer: |
    Although there were a few unit tests that tested code near the vulnerability-
    causing code, I couldn't identify any unit tests that specifically tested
    the section of the code relevant to 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.
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: |-
      Made changes to how the error log string is created. These changes

      played a minor part in the fix for the vulnerability.


      Formerly b8a310a5969e4ce61e40d3270369866190809ee8 before HTTPD rewrote Git history.
    commit: de46b1035ba54be2877227157ec32484c3a0045e
  - 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?
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: 
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: 
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.

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