CWE-641: Insufficient Filtering of File and Other Resource Names for Executable Content
Insufficient Filtering of File and Other Resource Names for Executable Content
Weakness ID: 641 (Weakness Variant)
Status: Incomplete
Description
Description Summary
When an application does not restrict the valid names of
resources (e.g. files) supplied by the user, various problems may arise down the
line when these resources are used.
Extended Description
For instance, if the names of these resources contain scripting
characters, it is possible that a script may get executed in the client's
browser if the application ever displays the name of the resource on a
dynamically generated webpage. Or if the resources are consumed by some
application parser, a specially crafted name can exploit some vulnerability
internal to the parser, potentially resulting in execution of arbitrary code
on the server machine. The problems will vary based on the context of usage
of such malformed resource names and whether vulnerabilities are present in
or assumptions are made by the targeted technology that would make code
execution possible.
Time of Introduction
Architecture and Design
Implementation
Applicable Platforms
Languages
All
Common Consequences
Scope
Effect
Integrity
Execution of arbitrary code in the context of usage of the resources
with dangerous names
Availability
Crash of the consumer code of these resources resulting in information
leakage or denial of service
Likelihood of Exploit
Low
Enabling Factors for Exploitation
Resource names are controllable by the user.
No sufficient validation of resource names at entry points or before
consumption by other processes.
Context where the resources are consumed makes execution of code possible
based on the names of the supplied resources.
Observed Examples
Reference
Description
Format string vulnerability in Dia 0.94 allows
user-assisted attackers to cause a denial of service (crash) and possibly
execute arbitrary code by triggering errors or warnings, as demonstrated via
format string specifiers in a .bmp filename. [CVE-2006-2480 available at:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-2480
]
Potential Mitigations
Phase
Description
Do not allow users to control names of resources used on the server
side.
Perform white list input validation at entry points and also before
consuming the resources. Reject bad file names rather than trying to
cleanse them.
Make sure that technologies consuming the resources are not vulnerable
(e.g. buffer overflow, format string, etc.) in a way that would allow
code execution if the name of the resource is malformed.
Description
