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ID

CWE-593: Authentication Bypass: OpenSSL CTX Object Modified after SSL Objects are Created

Weakness ID: 593
Abstraction: Variant
Status: Draft
Presentation Filter:
+ Description

Description Summary

The software modifies the SSL context after connection creation has begun.

Extended Description

If the program modifies the SSL_CTX object after creating SSL objects from it, there is the possibility that older SSL objects created from the original context could all be affected by that change.

+ Time of Introduction
  • Architecture and Design
  • Implementation
+ Common Consequences
ScopeEffect
Access Control

Technical Impact: Bypass protection mechanism

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

Confidentiality

Technical Impact: Read application data

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

+ Demonstrative Examples

Example 1

(Bad Code)
Example Language:
#define CERT "secret.pem"
#define CERT2 "secret2.pem"

int main(){
SSL_CTX *ctx;
SSL *ssl;
init_OpenSSL();
seed_prng();

ctx = SSL_CTX_new(SSLv23_method());

if (SSL_CTX_use_certificate_chain_file(ctx, CERT) != 1)
int_error("Error loading certificate from file");

if (SSL_CTX_use_PrivateKey_file(ctx, CERT, SSL_FILETYPE_PEM) != 1)
int_error("Error loading private key from file");

if (!(ssl = SSL_new(ctx)))
int_error("Error creating an SSL context");

if ( SSL_CTX_set_default_passwd_cb(ctx, "new default password" != 1))
int_error("Doing something which is dangerous to do anyways");

if (!(ssl2 = SSL_new(ctx)))
int_error("Error creating an SSL context");
}
+ Potential Mitigations

Phase: Architecture and Design

Use a language or a library that provides a cryptography framework at a higher level of abstraction.

Phase: Implementation

Most SSL_CTX functions have SSL counterparts that act on SSL-type objects.

Phase: Implementation

Applications should set up an SSL_CTX completely, before creating SSL objects from it.

+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfWeakness ClassWeakness Class287Improper Authentication
Development Concepts (primary)699
Research Concepts1000
ChildOfWeakness BaseWeakness Base666Operation on Resource in Wrong Phase of Lifetime
Research Concepts (primary)1000
ChildOfCategoryCategory948SFP Secondary Cluster: Digital Certificate
Software Fault Pattern (SFP) Clusters (primary)888
+ Content History
Modifications
Modification DateModifierOrganizationSource
2008-07-01Eric DalciCigitalExternal
updated Time_of_Introduction
2008-09-08CWE Content TeamMITREInternal
updated Common_Consequences, Relationships, Other_Notes
2009-07-27CWE Content TeamMITREInternal
updated Description, Other_Notes, Potential_Mitigations
2011-06-01CWE Content TeamMITREInternal
updated Common_Consequences
2011-06-27CWE Content TeamMITREInternal
updated Common_Consequences
2012-05-11CWE Content TeamMITREInternal
updated Relationships
2014-07-30CWE Content TeamMITREInternal
updated Relationships
2017-05-03CWE Content TeamMITREInternal
updated Potential_Mitigations, Relationships

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Page Last Updated: May 05, 2017