Difference between revisions of "Custom Special Character Injection"

Revision as of 12:38, 16 February 2009

This is an Attack. To view all attacks, please see the Attack Category page.

ASDR Table of Contents

Description

The software does not properly filter or quote special characters or reserved words that are used in a custom or proprietary language or representation that is used by the product. That allows attackers to modify the syntax, content, or commands before they are processed by the end system.

Risk Factors

TBD

Examples

Example1

A simple example is an application which executes almost everything which is passed to it from the current terminal by the user without sanitazing and blocking user input. If the application doesn't implement appropriate signals handling, we may interrupt or suspend program execution by sending respectively Ctrl+C (^C) or Ctrl+Z (^Z) combinations. These combinations are sending signals to the application. In the first case it's SIGINT and in the second it's SIGSTOP signal.

Example2

The classic example, often used by the IRC warriors/bandits, was disconnecting modem users by sending to them a special sequence of characters. Sending via any protocol (IP) "+++ATH0" sequence caused some modems to interpret this sequence as a disconnect command. So all that had to be done was to send the sequence on an IRC channel, which in effect forced vulnerable modems to disconnect.

Related Threat Agents

• Logic/time bomb

Related Attacks

• Log forging

Related Vulnerabilities

• TBD

Related Controls

• Category:Input Validation
• Output Validation
• Canonicalization

References

TBD