The web server must limit the character set used for data entry.
Overview
Finding ID
Version
Rule ID
IA Controls
Severity
V-206410
SRG-APP-000251-WSR-000157
SV-206410r961158_rule
Medium
Description
Invalid user input occurs when a user inserts data or characters into a hosted application's data entry field and the hosted application is unprepared to process that data. This results in unanticipated application behavior, potentially leading to an application compromise. Invalid user input is one of the primary methods employed when attempting to compromise an application.
An attacker can also enter Unicode into hosted applications in an effort to break out of the document home or root home directory or to bypass security checks.
The web server, by defining the character set available for data entry, can trap efforts to bypass security checks or to compromise an application.