Detailed attack pattern

Draft

CAPEC-32: XSS Through HTTP Query Strings

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.

High

Typical severity

Per MITRE

High

Likelihood of attack

Per MITRE

Related weaknesses

CWEs this targets

Detailed

Abstraction

MITRE classification

Overview

CAPEC-32 (XSS Through HTTP Query Strings) is a detailed-level attack pattern catalogued by MITRE in the Common Attack Pattern Enumeration and Classification (CAPEC). It describes a recurring method attackers use to exploit software weaknesses.

How the attack works

The phases an attacker typically follows to carry out this attack.

Step 1
Explore
[Survey the application for public links] Using a browser or an automated tool, an adversary follows all public links on a web site. They record all the links they find.
- 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.
Step 2
Experiment
[Probe public links for XSS vulnerability] The adversary uses the public links gathered in the "Explore" phase as a target list and requests variations on the URLs they spidered before. They send parameters that include variations of payloads. They record all the responses from the server that include unmodified versions of their 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.
Step 3
Experiment
[Craft malicious XSS URL] Once the adversary has determined which parameters are vulnerable to XSS, they will craft a malicious URL containing the XSS exploit. The adversary can have many goals, from stealing session IDs, cookies, credentials, and page content from the victim.
- Change a URL parameter to include a malicious script tag.
- Send information gathered from the malicious script to a remote endpoint.
Step 4
Exploit
[Get victim to click URL] In order for the attack to be successful, the victim needs to access the malicious URL.
- Send a phishing email to the victim containing the malicious URL. This can be hidden in a hyperlink as to not show the full URL, which might draw suspicion.
- Put the malicious URL on a public forum, where many victims might accidentally click the link.

CAPEC-32: XSS Through HTTP Query Strings

Overview

How the attack works

What the attacker needs

Prerequisites

Skills required

Resources required

Consequences

How to mitigate it

Examples

Frequently asked questions

What is CAPEC-32?

How does a XSS Through HTTP Query Strings attack work?

How do you prevent CAPEC-32?

What weaknesses does CAPEC-32 target?

How severe is CAPEC-32?

References

Defend against CAPEC-32

Overview

How the attack works

What the attacker needs

Prerequisites

Skills required

Resources required

Consequences

How to mitigate it

Examples

Related weaknesses

Related attack patterns

Parent

Frequently asked questions

What is CAPEC-32?

How does a XSS Through HTTP Query Strings attack work?

How do you prevent CAPEC-32?

What weaknesses does CAPEC-32 target?

How severe is CAPEC-32?

References

Defend against CAPEC-32