CWE-1312: Missing Protection for Mirrored Regions in On-Chip Fabric Firewall
Weakness ID: 1312
Vulnerability Mapping:ALLOWEDThis CWE ID may be used to map to real-world vulnerabilities Abstraction:
BaseBase - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
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Description
The firewall in an on-chip fabric protects the main addressed region, but it does not protect any mirrored memory or memory-mapped-IO (MMIO) regions.
Extended Description
Few fabrics mirror memory and address ranges, where mirrored regions contain copies of the original data. This redundancy is used to achieve fault tolerance. Whatever protections the fabric firewall implements for the original region should also apply to the mirrored regions. If not, an attacker could bypass existing read/write protections by reading from/writing to the mirrored regions to leak or corrupt the original data.
Common Consequences
This table specifies different individual consequences
associated with the weakness. The Scope identifies the application security area that is
violated, while the Impact describes the negative technical impact that arises if an
adversary succeeds in exploiting this weakness. The Likelihood provides information about
how likely the specific consequence is expected to be seen relative to the other
consequences in the list. For example, there may be high likelihood that a weakness will be
exploited to achieve a certain impact, but a low likelihood that it will be exploited to
achieve a different impact.
The fabric firewall should apply the same protections as the original region to the mirrored regions.
Phase: Implementation
The fabric firewall should apply the same protections as the original region to the mirrored regions.
Relationships
This table shows the weaknesses and high level categories that are related to this
weakness. These relationships are defined as ChildOf, ParentOf, MemberOf 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 the user
may want to explore.
Relevant to the view "Research Concepts" (CWE-1000)
Nature
Type
ID
Name
ChildOf
Pillar - a weakness that is the most abstract type of weakness and represents a theme for all class/base/variant weaknesses related to it. A Pillar is different from a Category as a Pillar is still technically a type of weakness that describes a mistake, while a Category represents a common characteristic used to group related things.
This table shows the weaknesses and high level categories that are related to this
weakness. These relationships are defined as ChildOf, ParentOf, MemberOf 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 the user
may want to explore.
Relevant to the view "Hardware Design" (CWE-1194)
Nature
Type
ID
Name
MemberOf
Category - a CWE entry that contains a set of other entries that share a common characteristic.
Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
The different Modes of Introduction provide information
about how and when this
weakness may be introduced. The Phase identifies a point in the life cycle at which
introduction
may occur, while the Note provides a typical scenario related to introduction during the
given
phase.
Phase
Note
Architecture and Design
Implementation
Applicable Platforms
This listing shows possible areas for which the given
weakness could appear. These
may be for specific named Languages, Operating Systems, Architectures, Paradigms,
Technologies,
or a class of such platforms. The platform is listed along with how frequently the given
weakness appears for that instance.
Languages
Class: Not Language-Specific
(Undetermined Prevalence)
Operating Systems
Class: Not OS-Specific
(Undetermined Prevalence)
Architectures
Class: Not Architecture-Specific
(Undetermined Prevalence)
Technologies
Class: Not Technology-Specific
(Undetermined Prevalence)
Demonstrative Examples
Example 1
A memory-controller IP block is connected to the on-chip fabric in a System on Chip (SoC). The memory controller is configured to divide the memory into four parts: one original and three mirrored regions inside the memory. The upper two bits of the address indicate which region is being addressed. 00 indicates the original region and 01, 10, and 11 are used to address the mirrored regions. All four regions operate in a lock-step manner and are always synchronized. The firewall in the on-chip fabric is programmed to protect the assets in the memory.
The firewall only protects the original range but not the mirrored regions.
The attacker (as an unprivileged user) sends a write transaction to the mirrored region. The mirrored region has an address with the upper two bits set to "10" and the remaining bits of the address pointing to an asset. The firewall does not block this write transaction. Once the write is successful, contents in the protected-memory region are also updated. Thus, the attacker can bypass existing, memory protections.
Firewall should protect mirrored regions.
Detection
Methods
Manual Dynamic Analysis
Using an external debugger, send write transactions to mirrored regions to test if original, write-protected regions are modified. Similarly, send read transactions to mirrored regions to test if the original, read-protected signals can be read.
Effectiveness: High
Memberships
This MemberOf Relationships table shows additional CWE Categories and Views that
reference this weakness as a member. This information is often useful in understanding where a
weakness fits within the context of external information sources.
Nature
Type
ID
Name
MemberOf
Category - a CWE entry that contains a set of other entries that share a common characteristic.
(this CWE ID may be used to map to real-world vulnerabilities)
Reason:
Acceptable-Use
Rationale:
This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comments:
Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.