An attacker modifies content to make it contain something other than what
the original content producer intended while keeping the apparent source of
the content unchanged. The term content spoofing is most often used to
describe modification of web pages hosted by a target to display the
attacker's content instead of the owner's content. However, any content can
be spoofed, including the content of email messages, file transfers, or the
content of other network communication protocols. Content can be modified at
the source (e.g. modifying the source file for a web page) or in transit
(e.g. intercepting and modifying a message between the sender and
recipient). Usually, the attacker will attempt to hide the fact that the
content has been modified, but in some cases, such as with web site
defacement, this is not necessary. Content Spoofing can lead to malware
exposure, financial fraud if the content governs financial transactions,
privacy violations, and other results.
The target must provide content but fail to adequately protect it against
No special resources are required by the client for most forms of the attack.
If the content is to be modified in transit, the attacker must be able to
intercept the targeted messages. In some variants, the targeted content is
altered so that all or some of it is redirected towards content published by the
attacker (for example, images and frames in the target's web site might be
modified to be loaded from a source controlled by the attacker). In these cases,
the attacker must be able to host the replacement content.