CWE - CWE-656: Reliance on Security Through Obscurity (4.4)

Weakness ID: 656

Abstraction: Base
Structure: Simple

Status: Draft

Presentation Filter:

Description

The software uses a protection mechanism whose strength depends heavily on its obscurity, such that knowledge of its algorithms or key data is sufficient to defeat the mechanism.

Extended Description

This reliance on "security through obscurity" can produce resultant weaknesses if an attacker is able to reverse engineer the inner workings of the mechanism. Note that obscurity can be one small part of defense in depth, since it can create more work for an attacker; however, it is a significant risk if used as the primary means of protection.

Alternate Terms

Never Assuming your secrets are safe

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	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.	693	Protection Mechanism Failure
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.	657	Violation of Secure Design Principles
PeerOf	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.	603	Use of Client-Side Authentication
CanPrecede	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	259	Use of Hard-coded Password
CanPrecede	Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.	321	Use of Hard-coded Cryptographic Key
CanPrecede	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.	472	External Control of Assumed-Immutable Web Parameter

Relevant to the view "Architectural Concepts" (CWE-1008)

Nature	Type	ID	Name
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1011	Authorize Actors

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.

Phase	Note
Architecture and Design
Implementation	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

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)

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.

Scope	Impact	Likelihood
Confidentiality Integrity Availability Other	Technical Impact: Other The security mechanism can be bypassed easily.

Demonstrative Examples

Example 1

The design of TCP relies on the secrecy of Initial Sequence Numbers (ISNs), as originally covered in CVE-1999-0077. If ISNs can be guessed (due to predictability, CWE-330) or sniffed (due to lack of encryption, CWE-311), then an attacker can hijack or spoof connections. Many TCP implementations have had variations of this problem over the years, including CVE-2004-0641, CVE-2002-1463, CVE-2001-0751, CVE-2001-0328, CVE-2001-0288, CVE-2001-0163, CVE-2001-0162, CVE-2000-0916, and CVE-2000-0328.

Example 1 References:

[REF-542] Jon Postel, Editor. "RFC: 793, TRANSMISSION CONTROL PROTOCOL". Information Sciences Institute. 1981-09. <http://www.ietf.org/rfc/rfc0793.txt>.

Observed Examples

Reference	Description
CVE-2006-6588	Reliance on hidden form fields in a web application. Many web application vulnerabilities exist because the developer did not consider that "hidden" form fields can be processed using a modified client.
CVE-2006-7142	Hard-coded cryptographic key stored in executable program.
CVE-2005-4002	Hard-coded cryptographic key stored in executable program.
CVE-2006-4068	Hard-coded hashed values for username and password contained in client-side script, allowing brute-force offline attacks.

Potential Mitigations

Phase: Architecture and Design

Always consider whether knowledge of your code or design is sufficient to break it. Reverse engineering is a highly successful discipline, and financially feasible for motivated adversaries. Black-box techniques are established for binary analysis of executables that use obfuscation, runtime analysis of proprietary protocols, inferring file formats, and others.

Phase: Architecture and Design

When available, use publicly-vetted algorithms and procedures, as these are more likely to undergo more extensive security analysis and testing. This is especially the case with encryption and authentication.

Weakness Ordinalities

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)

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.	975	SFP Secondary Cluster: Architecture

Notes

Relationship

Note that there is a close relationship between this weakness and CWE-603 (Use of Client-Side Authentication). If developers do not believe that a user can reverse engineer a client, then they are more likely to choose client-side authentication in the belief that it is safe.

References

[REF-196] Jerome H. Saltzer and Michael D. Schroeder. "The Protection of Information in Computer Systems". Proceedings of the IEEE 63. 1975-09. <http://web.mit.edu/Saltzer/www/publications/protection/>.

[REF-544] Sean Barnum and Michael Gegick. "Never Assuming that Your Secrets Are Safe". 2005-09-14. <https://buildsecurityin.us-cert.gov/daisy/bsi/articles/knowledge/principles/352.html>.

Content History

Submissions
Submission Date	Submitter	Organization
2008-01-18	Pascal Meunier	Purdue University
2008-01-18
Modifications
Modification Date	Modifier	Organization
2008-07-01	Eric Dalci	Cigital
2008-07-01	updated Time_of_Introduction
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Common_Consequences, Description, Relationships, Other_Notes, Weakness_Ordinalities
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Description, Name
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Related_Attack_Patterns
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Common_Consequences
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated Relationships
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Other_Notes, Relationship_Notes
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Relationships
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Applicable_Platforms, Causal_Nature, Modes_of_Introduction, Relationships
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Relationships, Time_of_Introduction
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated Relationships
Previous Entry Names
Change Date	Previous Entry Name
2009-01-12	Design Principle Violation: Reliance on Security through Obscurity


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Common Weakness Enumeration

CWE-656: Reliance on Security Through Obscurity