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CAPEC-32: XSS Through HTTP Query Strings

 
XSS Through HTTP Query Strings
Definition in a New Window Definition in a New Window
Attack Pattern ID: 32
Abstraction: Detailed
Status: Draft
Completeness: Complete
Presentation Filter:
+ Summary

An adversary embeds malicious script code in the parameters of an HTTP query string and convinces a victim to submit the HTTP request that contains the query string to a vulnerable web application. The web application then procedes to use the values parameters without properly validation them first and generates the HTML code that will be executed by the victim's browser.

+ Attack Steps
Explore
  1. Spider: Using a browser or an automated tool, an attacker follows all public links on a web site. He records all the links he finds.

    Use a spidering tool to follow and record all links. Make special note of any links that include parameters in the URL.

    Use a proxy tool to record all links visited during a manual traversal of the web application. Make special note of any links that include parameters in the URL. Manual traversal of this type is frequently necessary to identify forms that are GET method forms rather than POST forms.

    Use a browser to manually explore the website and analyze how it is constructed. Many browser's plugins are available to facilitate the analysis or automate the URL discovery.

Experiment
  1. Attempt variations on input parameters: Possibly using an automated tool, an attacker requests variations on the URLs he spidered before. He sends parameters that include variations of payloads. He records all the responses from the server that include unmodified versions of his script.

    Use a list of XSS probe strings to inject in parameters of known URLs. If possible, the probe strings contain a unique identifier.

    Use a proxy tool to record results of manual input of XSS probes in known URLs.

Exploit
  1. Steal session IDs, credentials, page content, etc.: As the attacker succeeds in exploiting the vulnerability, he can choose to steal user's credentials in order to reuse or to analyze them later on.

    Develop malicious JavaScript that is injected through vectors identified during the Experiment Phase and loaded by the victim's browser and sends document information to the attacker.

    Develop malicious JavaScript that injected through vectors identified during the Experiment Phase and takes commands from an attacker's server and then causes the browser to execute appropriately.

  2. Forceful browsing: When the attacker targets the current application or another one (through CSRF vulnerabilities), the user will then be the one who perform the attacks without being aware of it. These attacks are mostly targeting application logic flaws, but it can also be used to create a widespread attack against a particular website on the user's current network (Internet or not).

    Develop malicious JavaScript that is injected through vectors identified during the Experiment Phase and loaded by the victim's browser and performs actions on the same web site

    Develop malicious JavaScript that injected through vectors identified during the Experiment Phase and takes commands from an attacker's server and then causes the browser to execute request to other web sites (especially the web applications that have CSRF vulnerabilities).

  3. Content spoofing: By manipulating the content, the attacker targets the information that the user would like to get from the website.

    Develop malicious JavaScript that is injected through vectors identified during the Experiment Phase and loaded by the victim's browser and exposes attacker-modified invalid information to the user on the current web page.

+ Attack Prerequisites
  • Target client software must allow scripting such as JavaScript. Server software must allow display of remote generated HTML without sufficient input or output validation.

+ Typical Severity

High

+ Typical Likelihood of Exploit

Likelihood: High

+ Methods of Attack
  • Injection
  • Protocol Manipulation
+ Examples-Instances

Description

http://user:host@example.com:8080/oradb<script>alert('Hi')</script>

Description

Web applications that accept name value pairs in a HTTP Query string are inherently at risk to any value (or name for that matter) that an attacker would like to enter in the query string. This can be done manually via web browser or trivially scripted to post the query string to multiple sites. In the latter case, in the instance of many sites using similar infrastructure with predictable http queries being accepted and operated on (such as blogging software, Google applications, and so on), a single malicious payload can be scripted to target a wide variety of sites.

Web 2.0 type sites like Technorati and del.icio.us rely on user generated content like tags to build http links that are displayed to other users. del.icio.us allows users to identify sites, tag them with metadata and provide URL, descriptions and more data. This data is then echoed back to any other web browser that is interested in the link. If the data is not validated by the del.icio.us site properly then an arbitrary code can be added into the standard http string sent to del.icio.us by the attacker, for example formatted as normal content with a URL and description and tagged as Java, and available to be clicked on (and executed by) any user browsing for Java content that clicks on this trojaned content.

+ Attacker Skills or Knowledge Required

Skill or Knowledge Level: Low

To place malicious payload on server via HTTP

Skill or Knowledge Level: High

Exploiting any information gathered by HTTP Query on script host

+ Resources Required

Ability to send HTTP post to scripting host and collect output

+ Solutions and Mitigations

Design: Use browser technologies that do not allow client side scripting.

Design: Utilize strict type, character, and encoding enforcement

Design: Server side developers should not proxy content via XHR or other means, if a http proxy for remote content is setup on the server side, the client's browser has no way of discerning where the data is originating from.

Implementation: Ensure all content that is delivered to client is sanitized against an acceptable content specification.

Implementation: Perform input validation for all remote content, including remote and user-generated content

Implementation: Perform output validation for all remote content.

Implementation: Disable scripting languages such as JavaScript in browser

Implementation: Session tokens for specific host

Implementation: Patching software. There are many attack vectors for XSS on the client side and the server side. Many vulnerabilities are fixed in service packs for browser, web servers, and plug in technologies, staying current on patch release that deal with XSS countermeasures mitigates this.

Implementation: Privileges are constrained, if a script is loaded, ensure system runs in chroot jail or other limited authority mode

+ Attack Motivation-Consequences
ScopeTechnical ImpactNote
Confidentiality
Read application data
Confidentiality
Integrity
Availability
Execute unauthorized code or commands
Run Arbitrary Code
+ Injection Vector

Script delivered through standard web server, such as a web server with user-generated content.

+ Payload

HTTP Request Query String

+ Activation Zone

Client web browser where script is executed

+ Payload Activation Impact

Client web browser may be used to steal session data, passwords, cookies, and other tokens.

+ Purposes
  • Exploitation
+ CIA Impact
Confidentiality Impact: HighIntegrity Impact: HighAvailability Impact: Low
+ Technical Context
Architectural Paradigms
Client-Server
n-Tier
Frameworks
All
Platforms
All
Languages
All
+ References
[R.32.1] [REF-2] G. Hoglund and G. McGraw. "Exploiting Software: How to Break Code". Addison-Wesley. February 2004.
+ Content History
Submissions
SubmitterOrganizationDateSource
CAPEC Content TeamThe MITRE Corporation2014-06-23Internal_CAPEC_Team
Modifications
ModifierOrganizationDateCommentsSource
CAPEC Content TeamThe MITRE Corporation2015-11-09Updated Attack_PhasesInternal
CAPEC Content TeamThe MITRE Corporation2015-12-07Updated Attack_PhasesInternal
CAPEC Content TeamThe MITRE Corporation2017-01-09Updated Attack_PhasesInternal
CAPEC Content TeamThe MITRE Corporation2017-05-01Updated Attack_Phases, Description Summary, Related_Attack_Patterns, Related_WeaknessesInternal
CAPEC Content TeamThe MITRE Corporation2017-08-04Updated Attack_PhasesInternal
Previous Entry Names
DatePrevious Entry Name
2017-05-01Embedding Scripts in HTTP Query Strings

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Page Last Updated or Reviewed: July 31, 2017