1980
CWE-1191: On-Chip Debug and Test Interface With Improper Access Control
Weakness ID : 1191
Structure : Simple
Abstraction : Base
Description
The chip does not implement or does not correctly perform access control to check whether
users are authorized to access internal registers and test modes through the physical debug/test
interface.
Extended Description
A device's internal information may be accessed through a scan chain of interconnected internal
registers, usually through a JTAG interface. The JTAG interface provides access to these registers
in a serial fashion in the form of a scan chain for the purposes of debugging programs running on a
device. Since almost all information contained within a device may be accessed over this interface,
device manufacturers typically insert some form of authentication and authorization to prevent
unintended use of this sensitive information. This mechanism is implemented in addition to on-chip
protections that are already present.
If authorization, authentication, or some other form of access control is not implemented or not
implemented correctly, a user may be able to bypass on-chip protection mechanisms through the
debug interface.
Sometimes, designers choose not to expose the debug pins on the motherboard. Instead,
they choose to hide these pins in the intermediate layers of the board. This is primarily done to
work around the lack of debug authorization inside the chip. In such a scenario (without debug
authorization), when the debug interface is exposed, chip internals are accessible to an attacker.
Relationships
The table(s) below shows the weaknesses and high level categories that are related to this
weakness. These relationships are defined as ChildOf, ParentOf, MemberOr and give insight to
similar items that may exist at higher and lower levels of abstraction. In addition, relationships such
as PeerOf and CanAlsoBe are defined to show similar weaknesses that may want to be explored.
Relevant to the view "Research Concepts" (CWE-1000)
Nature Type ID Name Page
ChildOf 284 Improper Access Control 680
PeerOf 1263 Improper Physical Access Control 2085
Relevant to the view "Hardware Design" (CWE-1194)
Nature Type ID Name Page
PeerOf 1299 Missing Protection Mechanism for Alternate Hardware
Interface