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Common Weakness Enumeration

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Home > CWE List > CWE- Individual Dictionary Definition (4.14)  
ID

CWE-1316: Fabric-Address Map Allows Programming of Unwarranted Overlaps of Protected and Unprotected Ranges

Weakness ID: 1316
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 address map of the on-chip fabric has protected and unprotected regions overlapping, allowing an attacker to bypass access control to the overlapping portion of the protected region.
+ Extended Description

Various ranges can be defined in the system-address map, either in the memory or in Memory-Mapped-IO (MMIO) space. These ranges are usually defined using special range registers that contain information, such as base address and size. Address decoding is the process of determining for which range the incoming transaction is destined. To ensure isolation, ranges containing secret data are access-control protected.

Occasionally, these ranges could overlap. The overlap could either be intentional (e.g. due to a limited number of range registers or limited choice in choosing size of the range) or unintentional (e.g. introduced by errors). Some hardware designs allow dynamic remapping of address ranges assigned to peripheral MMIO ranges. In such designs, intentional address overlaps can be created through misconfiguration by malicious software. When protected and unprotected ranges overlap, an attacker could send a transaction and potentially compromise the protections in place, violating the principle of least privilege.

+ Relationships
Section HelpThis 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)
NatureTypeIDName
ChildOfPillarPillar - 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.284Improper Access Control
Section HelpThis 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)
NatureTypeIDName
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1203Peripherals, On-chip Fabric, and Interface/IO Problems
+ Modes Of Introduction
Section HelpThe 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.
PhaseNote
Architecture and Design
Implementation
+ Applicable Platforms
Section HelpThis 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

Bus/Interface Hardware (Undetermined Prevalence)

Class: Not Technology-Specific (Undetermined Prevalence)

+ Common Consequences
Section HelpThis 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.
ScopeImpactLikelihood
Confidentiality
Integrity
Access Control
Authorization

Technical Impact: Bypass Protection Mechanism; Read Memory; Modify Memory

Medium
+ Demonstrative Examples

Example 1

An on-chip fabric supports a 64KB address space that is memory-mapped. The fabric has two range registers that support creation of two protected ranges with specific size constraints--4KB, 8KB, 16KB or 32KB. Assets that belong to user A require 4KB, and those of user B require 20KB. Registers and other assets that are not security-sensitive require 40KB. One range register is configured to program 4KB to protect user A's assets. Since a 20KB range cannot be created with the given size constraints, the range register for user B's assets is configured as 32KB. The rest of the address space is left as open. As a result, some part of untrusted and open-address space overlaps with user B range.

The fabric does not support least privilege, and an attacker can send a transaction to the overlapping region to tamper with user B data.

Since range B only requires 20KB but is allotted 32KB, there is 12KB of reserved space. Overlapping this region of user B data, where there are no assets, with the untrusted space will prevent an attacker from tampering with user B data.

+ Observed Examples
ReferenceDescription
Attacker can modify MCHBAR register to overlap with an attacker-controlled region, which modification prevents the SENTER instruction from properly applying VT-d protection while a Measured Launch Environment is being launched.
+ Potential Mitigations

Phase: Architecture and Design

When architecting the address map of the chip, ensure that protected and unprotected ranges are isolated and do not overlap. When designing, ensure that ranges hardcoded in Register-Transfer Level (RTL) do not overlap.

Phase: Implementation

Ranges configured by firmware should not overlap. If overlaps are mandatory because of constraints such as a limited number of registers, then ensure that no assets are present in the overlapped portion.

Phase: Testing

Validate mitigation actions with robust testing.
+ Detection Methods

Automated Dynamic Analysis

Review address map in specification to see if there are any overlapping ranges.

Effectiveness: High

Manual Static Analysis

Negative testing of access control on overlapped ranges.

Effectiveness: High

+ Memberships
Section HelpThis 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.
NatureTypeIDName
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1396Comprehensive Categorization: Access Control
+ Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID could 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.
+ Notes

Maintenance

As of CWE 4.6, CWE-1260 and CWE-1316 are siblings under view 1000, but CWE-1260 might be a parent of CWE-1316. More analysis is warranted.
+ References
[REF-1137] Yuriy Bulygin, Oleksandr Bazhaniuk, Andrew Furtak, John Loucaides, Mikhail Gorobets. "BARing the System - New vulnerabilities in Coreboot & UEFI-based Systems". 2017. <https://www.c7zero.info/stuff/REConBrussels2017_BARing_the_system.pdf>.
+ Content History
+ Submissions
Submission DateSubmitterOrganization
2020-06-01
(CWE 4.3, 2020-12-10)
Arun Kanuparthi, Hareesh Khattri, Parbati Kumar MannaIntel Corporation
+ Modifications
Modification DateModifierOrganization
2021-10-28CWE Content TeamMITRE
updated Maintenance_Notes
2022-04-28CWE Content TeamMITRE
updated Applicable_Platforms, Related_Attack_Patterns
2022-06-28CWE Content TeamMITRE
updated Applicable_Platforms
2022-10-13CWE Content TeamMITRE
updated References
2023-01-31CWE Content TeamMITRE
updated Related_Attack_Patterns
2023-04-27CWE Content TeamMITRE
updated Relationships
2023-06-29CWE Content TeamMITRE
updated Mapping_Notes
Page Last Updated: February 29, 2024