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ID

CWE-1259: Improper Protection of Security Identifiers

Weakness ID: 1259
Abstraction: Base
Structure: Simple
Status: Incomplete
Presentation Filter:
+ Description
The product implements a Security Identifier mechanism to differentiate what actions are allowed or disallowed when a transaction originates from an entity. However, the Security Identifiers are improperly protected.
+ Extended Description

Systems-On-Chip (Integrated circuits and hardware engines) implement Security Identifiers to differentiate/identify actions originated from various agents. These actions could be ‘read’, ‘write’, ‘program’, ‘reset’, ‘fetch’, ‘compute’, etc. Security identifiers are assigned to every agent in the System that is either capable of generating an action or receiving an action from other agent. Every agent could be assigned a unique Security Identifier based on its trust level or privileges. Since the Security Identifiers are very important to achieve security in SoC, they should be protected properly. A common weakness that can exist is that the Security Identifiers are improperly protected. Consequently, the Security Identifier can be programmed by a malicious agent (i.e., the Security Identifier is mutable) to spoof the action as if it originated from a trusted agent.

+ 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, 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
PeerOfBaseBase - 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.1254Incorrect Comparison Logic Granularity
PeerOfBaseBase - 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.1270Generation of Incorrect Security Identifiers
+ 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.1198Privilege Separation and Access Control Issues
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1199General Circuit and Logic Design Concerns
+ Modes Of Introduction

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.

PhaseNote
Architecture and DesignSuch issues could be introduced during hardware architecture and design phases.
ImplementationSuch issues could be introduced during implementation and identified later during testing or system configuration phases.
+ Applicable Platforms
The listings below show 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: Language-Independent (Undetermined Prevalence)

Operating Systems

Class: OS-Independent (Undetermined Prevalence)

Architectures

Class: Architecture-Independent (Undetermined Prevalence)

Technologies

Processor IP Class: Technology-Independent (Undetermined Prevalence)

Class: System on Chip (Undetermined Prevalence)

+ Common Consequences

The table below 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
Availability
Access Control

Technical Impact: Modify Files or Directories; Execute Unauthorized Code or Commands; Bypass Protection Mechanism; Gain Privileges or Assume Identity; Modify Memory; Modify Memory; DoS: Crash, Exit, or Restart

High
+ Demonstrative Examples

Example 1

For example, consider a system with a register for storing AES key for encryption or decryption. The key is of 128 bits implemented as a set of four 32-bit registers. The key registers are assets, and register, AES_KEY_ACCESS_POLICY, is defined to provide necessary, access controls. The access-policy register defines which agents with a security identifier in the transaction can access the AES-key registers. Each bit in this 32-bit register defines a security identifier. There could be a maximum of 32 security identifiers that are allowed access to the AES-key registers. The number of the bit when set (i.e., “1”) allows respective action from an agent whose identity matches the number of the bit and, if “0” (i.e., Clear), disallows the respective action to that corresponding agent.

Let’s assume the system has two agents: a Main-controller and an Aux-controller. The respective Security Identifiers are “1” and “2”.

Register Description Default
AES_ENC_DEC_KEY_0 AES key [0:31] for encryption or decryption 0x00000000
AES_ENC_DEC_KEY_1 AES key [32:63] for encryption or decryption 0x00000000
AES_ENC_DEC_KEY_2 AES key [64:95] for encryption or decryption 0x00000000
AES_ENC_DEC_KEY_3 AES key [96:127] for encryption or decryption 0x00000000
AES_KEY_ACCESS_POLICY AES key access register [31:0] 0x00000002

An agent with Security Identifier “1” has access to AES_ENC_DEC_KEY_0 through AES_ENC_DEC_KEY_3 registers. As per the above access policy, the AES-Key-access policy allows access to the AES-key registers if the security identifier is “1”.

(bad code)
Example Language: Other 
The Aux-controller could program its Security Identifier to “1” from “2”.

The SoC does not properly protect the Security Identifier of the agents, and, hence, the Aux-controller in the above example can spoof the transaction (i.e., send the transaction as if it is coming from the Main-controller to access the access-controlled, AES-Key registers) by programming its Security Identifier to that of an agent that has access to the asset.

(good code)
Example Language: Other 
The SoC should protect the Security Identifiers. None of the agents in the SoC should have the ability to change the Security Identifier.
+ Potential Mitigations

Phases: Architecture and Design; Implementation

  • Protection of Security Identifiers must be reviewed for design inconsistency and common weaknesses.
  • Security-Identifier definition and programming flow must be tested in pre-silicon and post-silicon testing.
+ Notes

Maintenance

This entry is still in under development and will continue to see updates and content improvements. Currently it is expressed as a general absence of a protection mechanism as opposed to a specific mistake, and the entry's name and description could be interpreted as applying to software.
+ Content History
+ Submissions
Submission DateSubmitterOrganization
2020-03-06Arun Kanuparthi, Hareesh Khattri, Parbati Kumar Manna, Narasimha Kumar V MangipudiIntel Corporation
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Page Last Updated: June 25, 2020