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CWE
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Use of a Broken or Risky Cryptographic Algorithm

ID: 327Date: (C)2012-05-14   (M)2017-11-14
Type: weaknessStatus: DRAFT
Abstraction Type: Base





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.

Likelihood of Exploit: Medium to High

Applicable Platforms
Language Class: Language-independent

Time Of Introduction

  • Architecture and Design

Related Attack Patterns

Common Consequences

ScopeTechnical ImpactNotes
Confidentiality
 
Read application data
 
The confidentiality of sensitive data may be compromised by the use of a broken or risky cryptographic algorithm.
 
Integrity
 
Modify application data
 
The integrity of sensitive data may be compromised by the use of a broken or risky cryptographic algorithm.
 
Accountability
Non-Repudiation
 
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.
 

Detection Methods

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

Potential Mitigations

PhaseStrategyDescriptionEffectivenessNotes
Architecture and Design
 
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. [R.327.4]
 
  
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.
 
  
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.
 
  
Architecture and Design
 
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.
 
  
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.
 
  

Relationships

Related CWETypeViewChain
CWE-327 ChildOf CWE-903 Category CWE-888  

Demonstrative Examples   (Details)

  1. These code examples use the Data Encryption Standard (DES). Once considered a strong algorithm, it is now regarded as insufficient for many applications. It has been replaced by Advanced Encryption Standard (AES).

Observed Examples

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

For more examples, refer to CVE relations in the bottom box.

White Box Definitions
None

Black Box Definitions
None

Taxynomy Mappings

TaxynomyIdNameFit
CLASP  Using a broken or risky cryptographic algorithm
 
 
OWASP Top Ten 2004 A8
 
Insecure Storage
 
CWE_More_Specific
 
CERT Java Secure Coding MSC02-J
 
Generate strong random numbers
 
 
CERT C++ Secure Coding MSC30-CPP
 
Do not use the rand() function for generating pseudorandom numbers
 
 
CERT C++ Secure Coding MSC32-CPP
 
Ensure your random number generator is properly seeded
 
 

References:

  1. Bruce Schneier .Applied Cryptography. John Wiley & Sons. Published on 1996.
  2. Alfred J. Menezes Paul C. van Oorschot Scott A. Vanstone .Handbook of Applied Cryptography. Published on October 1996.
  3. C Matthew Curtin .Avoiding bogus encryption products: Snake Oil FAQ. 1998-04-10.
  4. Information Technology Laboratory, National Institute of Standards and Technology .SECURITY REQUIREMENTS FOR CRYPTOGRAPHIC MODULES. 2001-05-25.
  5. Paul F. Roberts .Microsoft Scraps Old Encryption in New Code. 2005-09-15.
  6. M. Howard D. LeBlanc .Writing Secure Code 2nd Edition. Microsoft. Section:'Chapter 8, "Cryptographic Foibles" Page 259'. Published on 2002.
  7. Michael Howard David LeBlanc John Viega .24 Deadly Sins of Software Security. McGraw-Hill. Section:'"Sin 21: Using the Wrong Cryptography." Page 315'. Published on 2010.
  8. Johannes Ullrich .Top 25 Series - Rank 24 - Use of a Broken or Risky Cryptographic Algorithm. SANS Software Security Institute. 2010-03-25.
  9. Mark Dowd John McDonald Justin Schuh .The Art of Software Security Assessment 1st Edition. Addison Wesley. Section:'Chapter 2, "Insufficient or Obsolete Encryption", Page 44.'. Published on 2006.

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