CWE-1282: Assumed-Immutable Data is Stored in Writable Memory
Weakness ID: 1282
Abstraction: Base Structure: Simple
Status: Incomplete
Presentation Filter:
Description
Immutable data, such as a first-stage bootloader, device identifiers, and "write-once" configuration settings are stored in writable memory that can be re-programmed or updated in the field.
Extended Description
Security services such as secure boot, authentication of code and data, and device attestation all require assets such as the first stage bootloader, public keys, golden hash digests, etc. which are implicitly trusted. Storing these assets in read-only memory (ROM), fuses, or one-time programmable (OTP) memory provides strong integrity guarantees and provides a root of trust for securing the rest of the system. Security is lost if assets assumed to be immutable can be modified.
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)
Nature
Type
ID
Name
ChildOf
Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.
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
Implementation
Keys, code, configuration settings, and other data should be programmed in write-once or read-only memory instead of writable memory.
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.
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.
Scope
Impact
Likelihood
Integrity
Technical Impact: Varies by Context
Demonstrative Examples
Example 1
Cryptographic hash functions are commonly used to create unique fixed-length digests used to ensure the integrity of code and keys. A golden digest is stored on the device and compared to the digest computed from the data to be verified. If the digests match, the data has not been maliciously modified. If an attacker can modify the golden digest they then have the ability to store arbitrary data that passes the verification check. Hash digests used to verify public keys and early stage boot code should be immutable, with the strongest protection offered by hardware immutability.
Potential Mitigations
Phase: Implementation
All immutable code or data should be programmed into ROM or write-once memory.
Notes
Maintenance
This entry is still in under development and will continue to see updates and content improvements, especially as it relates to CWE-1233.
Content History
Submissions
Submission Date
Submitter
Organization
2020-05-15
Nicole Fern
Tortuga Logic
Modifications
Modification Date
Modifier
Organization
2020-08-20
CWE Content Team
MITRE
updated Demonstrative_Examples, Description, Modes_of_Introduction, Name
Previous Entry Names
Change Date
Previous Entry Name
2020-08-20
Assumed-Immutable Data Stored in Writable Memory
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Description
