Description

The software checks the status of a file or directory before accessing it, which produces a race condition in which the file can be replaced with a link before the access is performed, causing the software to access the wrong file.

Extended Description

While developers might expect that there is a very narrow time window between the time of check and time of use, there is still a race condition. An attacker could cause the software to slow down (e.g. with memory consumption), causing the time window to become larger. Alternately, in some situations, the attacker could win the race by performing a large number of attacks.

Applicable Platforms
Language Class: All

Time Of Introduction

• Architecture and Design
• Implementation

Related Attack Patterns

• CAPEC-26

Common Consequences

Detection Methods
None

Potential Mitigations
None

Relationships
This is already covered by the "Link Following" weakness (CWE-59). It is included here because so many people associate race conditions with link problems; however, not all link following issues involve race conditions.

Demonstrative Examples   (Details)

1. This code prints the contents of a file if a user has permission. (Demonstrative Example Id DX-49)

White Box Definitions
None

Black Box Definitions
None

Taxynomy Mappings

References:

1. Mark Dowd John McDonald Justin Schuh .The Art of Software Security Assessment 1st Edition. Addison Wesley. Section:'Chapter 9, "Race Conditions", Page 526.'. Published on 2006.