Key Exchange without Entity Authentication
Weakness ID: 322 (Weakness Base)Status: Draft
+ Description

Description Summary

The software performs a key exchange with an actor without verifying the identity of that actor.

Extended Description

Performing a key exchange will preserve the integrity of the information sent between two entities, but this will not guarantee that the entities are who they claim they are. This may enable a set of "man-in-the-middle" attacks. Typically, this involves a victim client that contacts a malicious server that is impersonating a trusted server. If the client skips authentication or ignores an authentication failure, the malicious server may request authentication information from the user. The malicious server can then use this authentication information to log in to the trusted server using the victim's credentials, sniff traffic between the victim and trusted server, etc.

+ Time of Introduction
  • Architecture and Design
+ Applicable Platforms



+ Common Consequences

No authentication takes place in this process, bypassing an assumed protection of encryption.


The encrypted communication between a user and a trusted host may be subject to a "man-in-the-middle" sniffing attack.

+ Likelihood of Exploit


+ Demonstrative Examples

Example 1

Many systems have used Diffie-Hellman key exchange without authenticating the entities exchanging keys, leading to man-in-the-middle attacks. Many people using SSL/TLS skip the authentication (often unknowingly).

+ Potential Mitigations

Phase: Architecture and Design

Ensure that proper authentication is included in the system design.

Phase: Implementation

Understand and properly implement all checks necessary to ensure the identity of entities involved in encrypted communications.

+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfWeakness ClassWeakness Class287Improper Authentication
Research Concepts (primary)1000
ChildOfCategoryCategory320Key Management Errors
Development Concepts (primary)699
ChildOfWeakness ClassWeakness Class345Insufficient Verification of Data Authenticity
Research Concepts1000
PeerOfWeakness BaseWeakness Base296Improper Following of Chain of Trust for Certificate Validation
Research Concepts1000
PeerOfWeakness BaseWeakness Base298Improper Validation of Certificate Expiration
Research Concepts1000
PeerOfWeakness BaseWeakness Base299Improper Check for Certificate Revocation
Research Concepts1000
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
CLASPKey exchange without entity authentication
+ Content History
Submission DateSubmitterOrganizationSource
CLASPExternally Mined
Modification DateModifierOrganizationSource
2008-07-01Eric DalciCigitalExternal
updated Time of Introduction
2008-09-08CWE Content TeamMITREInternal
updated Common Consequences, Relationships, Other Notes, Taxonomy Mappings
2008-10-10CWE Content TeamMITREInternal
clarified the description
2008-10-14CWE Content TeamMITREInternal
updated Description, Other Notes
2009-07-27CWE Content TeamMITREInternal
updated Relationships