CWE

Partial Comparison

ID: 187		Date: (C)2012-05-14   (M)2022-10-10
Type: weakness		Status: INCOMPLETE
Abstraction Type: Base

Description

The software performs a comparison that only examines a portion of a factor before determining whether there is a match, such as a substring, leading to resultant weaknesses.

Extended Description

For example, an attacker might succeed in authentication by providing a small password that matches the associated portion of the larger, correct password.

Applicable Platforms
Language Class: All

Time Of Introduction

• Implementation

Common Consequences

Scope	Technical Impact	Notes
Integrity Access_Control	Alter execution logic Bypass protection mechanism

Detection Methods
None

Potential Mitigations

Phase	Strategy	Description	Effectiveness	Notes
Testing		Thoroughly test the comparison scheme before deploying code into production. Perform positive testing as well as negative testing.

Relationships
This is conceptually similar to other weaknesses, such as insufficient verification and regular expression errors. It is primary to some weaknesses.

Related CWE	Type	View	Chain
CWE-187 ChildOf CWE-907	Category	CWE-888

Demonstrative Examples   (Details)

1. This example defines a fixed username and password. The AuthenticateUser() function is intended to accept a username and a password from an untrusted user, and check to ensure that it matches the username and password. If the username and password match, AuthenticateUser() is intended to indicate that authentication succeeded.

Observed Examples

1. CVE-2004-1012 : Argument parser of an IMAP server treats a partial command "body[p" as if it is "body.peek", leading to index error and out-of-bounds corruption.
2. CVE-2004-0765 : Web browser only checks the hostname portion of a certificate when the hostname portion of the URI is not a fully qualified domain name (FQDN), which allows remote attackers to spoof trusted certificates.
3. CVE-2002-1374 : One-character password by attacker checks only against first character of real password.
4. CVE-2000-0979 : One-character password by attacker checks only against first character of real password.

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

White Box Definitions
None

Black Box Definitions
None

Taxynomy Mappings

Taxynomy	Id	Name	Fit
PLOVER		Partial Comparison

References:
None