An attack of this type involves an attacker inserting malicious characters
(such as a XSS redirection) into a filename, directly or indirectly that is
then used by the target software to generate HTML text or other potentially
executable content. Many websites rely on user-generated content and
dynamically build resources like files, filenames, and URL links directly
from user supplied data. In this attack pattern, the attacker uploads code
that can execute in the client browser and/or redirect the client browser to
a site that the attacker owns. All XSS attack payload variants can be used
to pass and exploit these vulnerabilities.
Attack Prerequisites
The victim must trust the name and locale of user controlled
filenames.
Typical Likelihood of Exploit
Likelihood: High
Methods of Attack
Modification of Resources
Examples-Instances
Description
Phishing attacks rely on a user clicking on links on that are supplied
to them by attackers masquerading as a trusted resource such as a bank
or online auction site. The end user's email client hosts the supplid
resource name in this case via email. The resource name, however may
either 1) direct the client browser to a malicious site to steal
credentical and/or 2) execute code on the client machine to probe the
victim's host system and network environment.
Attacker Skills or Knowledge Required
Skill or Knowledge Level: Low
To achieve a redirection and use of less trusted source, an attacker
can simply edit data that the host uses to build the filename
Skill or Knowledge Level: Medium
Deploying a malicious "look a like" site (such as a site masquerading
as a bank or online auction site) that the user enters their
authentication data into.
Skill or Knowledge Level: High
Exploiting a client side vulnerability to inject malicious scripts
into the browser's executable process.
Solutions and Mitigations
Design: Use browser technologies that do not allow client side
scripting.
Implementation: Ensure all content that is delivered to client is
sanitized against an acceptable content specification.
Implementation: Perform input validation for all remote content.
Implementation: Perform output validation for all remote content.
Implementation: Disable scripting languages such as Javascript in
browser
Implementation: Scan dynamically generated content against validation
specification
Attack Motivation-Consequences
Scope
Technical Impact
Note
Confidentiality
Access_Control
Authorization
Gain privileges / assume
identity
Confidentiality
Integrity
Availability
Execute unauthorized code or
commands
Availability
Alter execution
logic
Confidentiality
Read application
data
Injection Vector
Payload delivered through user controlled filename.
Payload
Command(s) executed directly on host
Activation Zone
Client machine and client network
Payload Activation Impact
Description
Enables attacker to execute server side code with any commands that the
program owner has privileges to.
Description
