|
Threats to Security Models and Architectures
Covert Channels:
Is a way for an entity to receive information in an unauthorized manner. It is an information flow that is not controlled by a security mechanism.
Covert timing channel - One process relays information to another by modulating its use of system resources.
Covert storage channel - When a process writes data to a storage location and another process directly or indirectly reads it. The problem occurs when the processes are at different security levels, and therefore not supposed to be sharing sensitive data.
- Countermeasures:
There is not much a user can do to countermeasure these channels.
For trojan horses that uses HTTP, intrusion detection and auditing may detect a covert channel.
Back Doors:
Also called maintenance hooks.
Are instructions within software that only the developer knows about and can invoke.
- Countermeasures:
Code reviews and unit and integration testing should always be looking out for back doors.
Preventative measures against back doors -
Host intrusion detection system
Use File system permissions to protect configuration files and sensitive information from being modified.
Strict access control.
File system encryption.
Auditing
Timing Issues:
Also called asynchronous attack.
Deals with the timing difference of the sequences of steps a system uses to complete a task.
A time-of-check versus time-of-use attack, also called race conditions, could replace autoexec.bat.
- Countermeasures:
Host intrusion detection system
File system permissions and encryption
Strict access control measures
Auditing
Buffer Overflows:
Sometimes referred to "smashing the stack"
When programs do not check the length of data that is inputted into a program and then processed by the CPU.
- Countermeasures
Proper programming and good coding practices.
Host intrusion detection system
File system permission and encryption
Strict access control
Auditing
|
|
