CWE-757 Detail

CWE-757

Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')
Incomplete
2009-03-10
00h00 +00:00
2023-06-29
00h00 +00:00
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Name: Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')

A protocol or its implementation supports interaction between multiple actors and allows those actors to negotiate which algorithm should be used as a protection mechanism such as encryption or authentication, but it does not select the strongest algorithm that is available to both parties.

CWE Description

When a security mechanism can be forced to downgrade to use a less secure algorithm, this can make it easier for attackers to compromise the product by exploiting weaker algorithm. The victim might not be aware that the less secure algorithm is being used. For example, if an attacker can force a communications channel to use cleartext instead of strongly-encrypted data, then the attacker could read the channel by sniffing, instead of going through extra effort of trying to decrypt the data using brute force techniques.

General Informations

Modes Of Introduction

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

Common Consequences

Scope Impact Likelihood
Access ControlBypass Protection Mechanism

Observed Examples

References Description

CVE-2006-4302

Attacker can select an older version of the software to exploit its vulnerabilities.

CVE-2006-4407

Improper prioritization of encryption ciphers during negotiation leads to use of a weaker cipher.

CVE-2005-2969

chain: SSL/TLS implementation disables a verification step (CWE-325) that enables a downgrade attack to a weaker protocol.

CVE-2001-1444

Telnet protocol implementation allows downgrade to weaker authentication and encryption using an Adversary-in-the-Middle AITM attack.

CVE-2002-1646

SSH server implementation allows override of configuration setting to use weaker authentication schemes. This may be a composite with CWE-642.

Detection Methods

Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
Effectiveness : High

Vulnerability Mapping Notes

Justification : This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Comment : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Related Attack Patterns

CAPEC-ID Attack Pattern Name
CAPEC-220 Client-Server Protocol Manipulation
An adversary takes advantage of weaknesses in the protocol by which a client and server are communicating to perform unexpected actions. Communication protocols are necessary to transfer messages between client and server applications. Moreover, different protocols may be used for different types of interactions.
CAPEC-606 Weakening of Cellular Encryption
An attacker, with control of a Cellular Rogue Base Station or through cooperation with a Malicious Mobile Network Operator can force the mobile device (e.g., the retransmission device) to use no encryption (A5/0 mode) or to use easily breakable encryption (A5/1 or A5/2 mode).
CAPEC-620 Drop Encryption Level
An attacker forces the encryption level to be lowered, thus enabling a successful attack against the encrypted data.

NotesNotes

This is related to CWE-300, although not all downgrade attacks necessarily require an entity that redirects or interferes with the network. See examples.

Submission

Name Organization Date Date release Version
CWE Content Team MITRE 2009-03-03 +00:00 2009-03-10 +00:00 1.3

Modifications

Name Organization Date Comment
CWE Content Team MITRE 2010-04-05 +00:00 updated Related_Attack_Patterns
CWE Content Team MITRE 2011-06-01 +00:00 updated Common_Consequences
CWE Content Team MITRE 2012-05-11 +00:00 updated Relationships
CWE Content Team MITRE 2014-07-30 +00:00 updated Relationships
CWE Content Team MITRE 2017-01-19 +00:00 updated Related_Attack_Patterns, Relationships
CWE Content Team MITRE 2017-11-08 +00:00 updated Modes_of_Introduction, Relationships
CWE Content Team MITRE 2019-06-20 +00:00 updated Type
CWE Content Team MITRE 2020-02-24 +00:00 updated Observed_Examples, Relationship_Notes, Relationships
CWE Content Team MITRE 2020-12-10 +00:00 updated Relationships
CWE Content Team MITRE 2021-07-20 +00:00 updated Observed_Examples
CWE Content Team MITRE 2021-10-28 +00:00 updated Relationships
CWE Content Team MITRE 2023-01-31 +00:00 updated Description
CWE Content Team MITRE 2023-04-27 +00:00 updated Detection_Factors, Relationships
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes