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

Weakness ID: 593
Abstraction: Variant
Structure: Simple
Status: Draft
Presentation Filter:
+ Description
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.
+ 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)
+ Relevant to the view "Architectural Concepts" (CWE-1008)
MemberOfCategoryCategory1010Authenticate Actors
+ Relevant to the view "Development Concepts" (CWE-699)
ChildOfClassClass287Improper Authentication
+ 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 software life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.

Architecture and Design
ImplementationREALIZATION: This weakness is caused during implementation of an architectural security tactic.
+ 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.

Access Control

Technical Impact: Bypass Protection Mechanism

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

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

The following example demonstrates the weakness.

(bad code)
Example Language:
#define CERT "secret.pem"
#define CERT2 "secret2.pem"

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

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.
+ 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.
MemberOfCategoryCategory948SFP Secondary Cluster: Digital Certificate
+ Content History
Modification DateModifierOrganization
2008-07-01Eric DalciCigital
updated Time_of_Introduction
2008-09-08CWE Content TeamMITRE
updated Common_Consequences, Relationships, Other_Notes
2009-07-27CWE Content TeamMITRE
updated Description, Other_Notes, Potential_Mitigations
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2011-06-27CWE Content TeamMITRE
updated Common_Consequences
2012-05-11CWE Content TeamMITRE
updated Relationships
2014-07-30CWE Content TeamMITRE
updated Relationships
2017-05-03CWE Content TeamMITRE
updated Potential_Mitigations, Relationships
2017-11-08CWE Content TeamMITRE
updated Demonstrative_Examples, Modes_of_Introduction, Relationships

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Page Last Updated: January 18, 2018