CWE - CWE-327: Use of a Broken or Risky Cryptographic Algorithm (4.5)

Weakness ID: 327

Abstraction: Class
Structure: Simple

Status: Draft

Presentation Filter:

Description

The use of a broken or risky cryptographic algorithm is an unnecessary risk that may result in the exposure of sensitive information.

Extended Description

The use of a non-standard algorithm is dangerous because a determined attacker may be able to break the algorithm and compromise whatever data has been protected. Well-known techniques may exist to break the algorithm.

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.	693	Protection Mechanism Failure
ParentOf	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.	328	Reversible One-Way Hash
ParentOf	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.	780	Use of RSA Algorithm without OAEP
ParentOf	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.	916	Use of Password Hash With Insufficient Computational Effort
ParentOf	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.	1240	Use of a Risky Cryptographic Primitive
PeerOf	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.	311	Missing Encryption of Sensitive Data
PeerOf	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.	301	Reflection Attack in an Authentication Protocol
CanFollow	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.	208	Observable Timing Discrepancy

Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (CWE-1003)

Nature	Type	ID	Name
ParentOf	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.	916	Use of Password Hash With Insufficient Computational Effort

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.	1013	Encrypt Data

Background Details

Cryptographic algorithms are the methods by which data is scrambled. There are a small number of well-understood and heavily studied algorithms that should be used by most applications. It is quite difficult to produce a secure algorithm, and even high profile algorithms by accomplished cryptographic experts have been broken.

Since the state of cryptography advances so rapidly, it is common for an algorithm to be considered "unsafe" even if it was once thought to be strong. This can happen when new attacks against the algorithm are discovered, or if computing power increases so much that the cryptographic algorithm no longer provides the amount of protection that was originally thought.

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	COMMISSION: This weakness refers to an incorrect design related to an architectural security tactic.

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: Language-Independent (Undetermined Prevalence)

Technologies

Class: Technology-Independent (Undetermined Prevalence)

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.

Scope	Impact	Likelihood
Confidentiality	Technical Impact: Read Application Data The confidentiality of sensitive data may be compromised by the use of a broken or risky cryptographic algorithm.
Integrity	Technical Impact: Modify Application Data The integrity of sensitive data may be compromised by the use of a broken or risky cryptographic algorithm.
Accountability Non-Repudiation	Technical Impact: Hide Activities If the cryptographic algorithm is used to ensure the identity of the source of the data (such as digital signatures), then a broken algorithm will compromise this scheme and the source of the data cannot be proven.

Likelihood Of Exploit

High

Demonstrative Examples

Example 1

These code examples use the Data Encryption Standard (DES).

(bad code)

Example Language: C

EVP_des_ecb();

(bad code)

Example Language: Java

Cipher des=Cipher.getInstance("DES...");
des.initEncrypt(key2);

(bad code)

Example Language: PHP

function encryptPassword($password){

$iv_size = mcrypt_get_iv_size(MCRYPT_DES, MCRYPT_MODE_ECB);
$iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
$key = "This is a password encryption key";
$encryptedPassword = mcrypt_encrypt(MCRYPT_DES, $key, $password, MCRYPT_MODE_ECB, $iv);
return $encryptedPassword;

}

Once considered a strong algorithm, DES now regarded as insufficient for many applications. It has been replaced by Advanced Encryption Standard (AES).

Observed Examples

Reference	Description
CVE-2008-3775	Product uses "ROT-25" to obfuscate the password in the registry.
CVE-2007-4150	product only uses "XOR" to obfuscate sensitive data
CVE-2007-5460	product only uses "XOR" and a fixed key to obfuscate sensitive data
CVE-2005-4860	Product substitutes characters with other characters in a fixed way, and also leaves certain input characters unchanged.
CVE-2002-2058	Attackers can infer private IP addresses by dividing each octet by the MD5 hash of '20'.
CVE-2008-3188	Product uses DES when MD5 has been specified in the configuration, resulting in weaker-than-expected password hashes.
CVE-2005-2946	Default configuration of product uses MD5 instead of stronger algorithms that are available, simplifying forgery of certificates.
CVE-2007-6013	Product uses the hash of a hash for authentication, allowing attackers to gain privileges if they can obtain the original hash.

Potential Mitigations

Phase: Architecture and Design

Strategy: Libraries or Frameworks

When there is a need to store or transmit sensitive data, use strong, up-to-date cryptographic algorithms to encrypt that data. Select a well-vetted algorithm that is currently considered to be strong by experts in the field, and use well-tested implementations. As with all cryptographic mechanisms, the source code should be available for analysis.

For example, US government systems require FIPS 140-2 certification.

Do not develop custom or private cryptographic algorithms. They will likely be exposed to attacks that are well-understood by cryptographers. Reverse engineering techniques are mature. If the algorithm can be compromised if attackers find out how it works, then it is especially weak.

Periodically ensure that the cryptography has not become obsolete. Some older algorithms, once thought to require a billion years of computing time, can now be broken in days or hours. This includes MD4, MD5, SHA1, DES, and other algorithms that were once regarded as strong. [REF-267]

Phase: Architecture and Design

Design the software so that one cryptographic algorithm can be replaced with another. This will make it easier to upgrade to stronger algorithms.

Phase: Architecture and Design

Carefully manage and protect cryptographic keys (see CWE-320). If the keys can be guessed or stolen, then the strength of the cryptography itself is irrelevant.

Phase: Architecture and Design

Strategy: Libraries or Frameworks

Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.

Industry-standard implementations will save development time and may be more likely to avoid errors that can occur during implementation of cryptographic algorithms. Consider the ESAPI Encryption feature.

Phases: Implementation; Architecture and Design

When using industry-approved techniques, use them correctly. Don't cut corners by skipping resource-intensive steps (CWE-325). These steps are often essential for preventing common attacks.

Detection Methods

Automated Analysis

Automated methods may be useful for recognizing commonly-used libraries or features that have become obsolete.

Effectiveness: Moderate

Note: False negatives may occur if the tool is not aware of the cryptographic libraries in use, or if custom cryptography is being used.

Manual Analysis

This weakness can be detected using tools and techniques that require manual (human) analysis, such as penetration testing, threat modeling, and interactive tools that allow the tester to record and modify an active session.

Note: These may be more effective than strictly automated techniques. This is especially the case with weaknesses that are related to design and business rules.

Automated Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Bytecode Weakness Analysis - including disassembler + source code weakness analysis

Binary Weakness Analysis - including disassembler + source code weakness analysis

Binary / Bytecode simple extractor - strings, ELF readers, etc.

Effectiveness: SOAR Partial

Manual Static Analysis - Binary or Bytecode

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Binary / Bytecode disassembler - then use manual analysis for vulnerabilities & anomalies

Effectiveness: SOAR Partial

Dynamic Analysis with Automated Results Interpretation

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Web Application Scanner

Web Services Scanner

Database Scanners

Effectiveness: SOAR Partial

Dynamic Analysis with Manual Results Interpretation

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Man-in-the-middle attack tool

Cost effective for partial coverage:

Framework-based Fuzzer

Automated Monitored Execution

Monitored Virtual Environment - run potentially malicious code in sandbox / wrapper / virtual machine, see if it does anything suspicious

Effectiveness: High

Manual Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Manual Source Code Review (not inspections)

Cost effective for partial coverage:

Focused Manual Spotcheck - Focused manual analysis of source

Effectiveness: High

Automated Static Analysis - Source Code

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Source code Weakness Analyzer

Context-configured Source Code Weakness Analyzer

Effectiveness: High

Automated Static Analysis

According to SOAR, the following detection techniques may be useful:

Cost effective for partial coverage:

Configuration Checker

Effectiveness: SOAR Partial

Architecture or Design Review

According to SOAR, the following detection techniques may be useful:

Highly cost effective:

Formal Methods / Correct-By-Construction

Cost effective for partial coverage:

Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

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.	729	OWASP Top Ten 2004 Category A8 - Insecure Storage
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	753	2009 Top 25 - Porous Defenses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	803	2010 Top 25 - Porous Defenses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	816	OWASP Top Ten 2010 Category A7 - Insecure Cryptographic Storage
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	866	2011 Top 25 - Porous Defenses
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	883	CERT C++ Secure Coding Section 49 - Miscellaneous (MSC)
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	884	CWE Cross-section
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	934	OWASP Top Ten 2013 Category A6 - Sensitive Data Exposure
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	958	SFP Secondary Cluster: Broken Cryptography
MemberOf	View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).	1003	Weaknesses for Simplified Mapping of Published Vulnerabilities
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1029	OWASP Top Ten 2017 Category A3 - Sensitive Data Exposure
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1131	CISQ Quality Measures (2016) - Security
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1152	SEI CERT Oracle Secure Coding Standard for Java - Guidelines 49. Miscellaneous (MSC)
MemberOf	Category - a CWE entry that contains a set of other entries that share a common characteristic.	1170	SEI CERT C Coding Standard - Guidelines 48. Miscellaneous (MSC)

Taxonomy Mappings

Mapped Taxonomy Name	Node ID	Fit	Mapped Node Name
CLASP			Using a broken or risky cryptographic algorithm
OWASP Top Ten 2004	A8	CWE More Specific	Insecure Storage
CERT C Secure Coding	MSC30-C	CWE More Abstract	Do not use the rand() function for generating pseudorandom numbers
CERT C Secure Coding	MSC32-C	CWE More Abstract	Properly seed pseudorandom number generators
The CERT Oracle Secure Coding Standard for Java (2011)	MSC02-J		Generate strong random numbers
OMG ASCSM	ASCSM-CWE-327

Related Attack Patterns

CAPEC-ID	Attack Pattern Name
CAPEC-20	Encryption Brute Forcing
CAPEC-459	Creating a Rogue Certification Authority Certificate
CAPEC-473	Signature Spoof
CAPEC-475	Signature Spoofing by Improper Validation
CAPEC-608	Cryptanalysis of Cellular Encryption
CAPEC-614	Rooting SIM Cards
CAPEC-97	Cryptanalysis

References

[REF-280] Bruce Schneier. "Applied Cryptography". John Wiley & Sons. 1996. <http://www.schneier.com/book-applied.html>.

[REF-281] Alfred J. Menezes, Paul C. van Oorschot and Scott A. Vanstone. "Handbook of Applied Cryptography". 1996-10. <http://www.cacr.math.uwaterloo.ca/hac/>.

[REF-282] C Matthew Curtin. "Avoiding bogus encryption products: Snake Oil FAQ". 1998-04-10. <http://www.faqs.org/faqs/cryptography-faq/snake-oil/>.

[REF-267] Information Technology Laboratory, National Institute of Standards and Technology. "SECURITY REQUIREMENTS FOR CRYPTOGRAPHIC MODULES". 2001-05-25. <http://csrc.nist.gov/publications/fips/fips140-2/fips1402.pdf>.

[REF-284] Paul F. Roberts. "Microsoft Scraps Old Encryption in New Code". 2005-09-15. <http://www.eweek.com/c/a/Security/Microsoft-Scraps-Old-Encryption-in-New-Code/>.

[REF-7] Michael Howard and David LeBlanc. "Writing Secure Code". Chapter 8, "Cryptographic Foibles" Page 259. 2nd Edition. Microsoft Press. 2002-12-04. <https://www.microsoftpressstore.com/store/writing-secure-code-9780735617223>.

[REF-44] Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 21: Using the Wrong Cryptography." Page 315. McGraw-Hill. 2010.

[REF-287] Johannes Ullrich. "Top 25 Series - Rank 24 - Use of a Broken or Risky Cryptographic Algorithm". SANS Software Security Institute. 2010-03-25. <http://blogs.sans.org/appsecstreetfighter/2010/03/25/top-25-series-rank-24-use-of-a-broken-or-risky-cryptographic-algorithm/>.

[REF-62] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 2, "Insufficient or Obsolete Encryption", Page 44. 1st Edition. Addison Wesley. 2006.

[REF-962] Object Management Group (OMG). "Automated Source Code Security Measure (ASCSM)". ASCSM-CWE-327. 2016-01. <http://www.omg.org/spec/ASCSM/1.0/>.

[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>.

Content History

Submissions
Submission Date	Submitter	Organization
2006-07-19	CLASP
2006-07-19
Modifications
Modification Date	Modifier	Organization
2008-08-15		Veracode
2008-08-15	Suggested OWASP Top Ten 2004 mapping
2008-09-08	CWE Content Team	MITRE
2008-09-08	updated Background_Details, Common_Consequences, Description, Relationships, Taxonomy_Mappings
2009-01-12	CWE Content Team	MITRE
2009-01-12	updated Demonstrative_Examples, Description, Observed_Examples, Potential_Mitigations, References, Relationships
2009-03-10	CWE Content Team	MITRE
2009-03-10	updated Potential_Mitigations
2009-07-27	CWE Content Team	MITRE
2009-07-27	updated Maintenance_Notes, Relationships
2009-10-29	CWE Content Team	MITRE
2009-10-29	updated Relationships
2009-12-28	CWE Content Team	MITRE
2009-12-28	updated References
2010-02-16	CWE Content Team	MITRE
2010-02-16	updated Detection_Factors, References, Relationships
2010-04-05	CWE Content Team	MITRE
2010-04-05	updated Applicable_Platforms, Potential_Mitigations, Related_Attack_Patterns
2010-06-21	CWE Content Team	MITRE
2010-06-21	updated Common_Consequences, Detection_Factors, Potential_Mitigations, References, Relationships
2010-09-27	CWE Content Team	MITRE
2010-09-27	updated Potential_Mitigations, Relationships
2011-03-29	CWE Content Team	MITRE
2011-03-29	updated Demonstrative_Examples, Description
2011-06-01	CWE Content Team	MITRE
2011-06-01	updated Relationships, Taxonomy_Mappings
2011-06-27	CWE Content Team	MITRE
2011-06-27	updated Relationships
2011-09-13	CWE Content Team	MITRE
2011-09-13	updated Potential_Mitigations, Relationships, Taxonomy_Mappings
2012-05-11	CWE Content Team	MITRE
2012-05-11	updated References, Related_Attack_Patterns, Relationships, Taxonomy_Mappings
2012-10-30	CWE Content Team	MITRE
2012-10-30	updated Potential_Mitigations
2013-02-21	CWE Content Team	MITRE
2013-02-21	updated Relationships
2014-02-18	CWE Content Team	MITRE
2014-02-18	updated Related_Attack_Patterns
2014-06-23	CWE Content Team	MITRE
2014-06-23	updated Relationships
2014-07-30	CWE Content Team	MITRE
2014-07-30	updated Demonstrative_Examples, Detection_Factors, Relationships
2015-12-07	CWE Content Team	MITRE
2015-12-07	updated Relationships
2017-01-19	CWE Content Team	MITRE
2017-01-19	updated Related_Attack_Patterns
2017-11-08	CWE Content Team	MITRE
2017-11-08	updated Demonstrative_Examples, Likelihood_of_Exploit, Modes_of_Introduction, References, Relationships, Taxonomy_Mappings
2018-03-27	CWE Content Team	MITRE
2018-03-27	updated References, Relationships
2019-01-03	CWE Content Team	MITRE
2019-01-03	updated References, Relationships, Taxonomy_Mappings
2019-06-20	CWE Content Team	MITRE
2019-06-20	updated Related_Attack_Patterns, Relationships, Type
2020-02-24	CWE Content Team	MITRE
2020-02-24	updated Applicable_Platforms, Detection_Factors, Maintenance_Notes, Relationships
2021-03-15	CWE Content Team	MITRE
2021-03-15	updated References
Previous Entry Names
Change Date	Previous Entry Name
2008-04-11	Using a Broken or Risky Cryptographic Algorithm


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Common Weakness Enumeration

CWE-327: Use of a Broken or Risky Cryptographic Algorithm