CWE

Common Weakness Enumeration

A Community-Developed List of Software Weakness Types

CWE/SANS Top 25 Most Dangerous Software Errors
Home > CWE List > CWE- Individual Dictionary Definition (2.10)  
ID

CWE-650: Trusting HTTP Permission Methods on the Server Side

Weakness ID: 650
Abstraction: Variant
Status: Incomplete
Presentation Filter:
+ Description

Description Summary

The server contains a protection mechanism that assumes that any URI that is accessed using HTTP GET will not cause a state change to the associated resource. This might allow attackers to bypass intended access restrictions and conduct resource modification and deletion attacks, since some applications allow GET to modify state.

Extended Description

An application may disallow the HTTP requests to perform DELETE, PUT and POST operations on the resource representation, believing that it will be enough to prevent unintended resource alterations. Even though the HTTP GET specification requires that GET requests should not have side effects, there is nothing in the HTTP protocol itself that prevents the HTTP GET method from performing more than just query of the data. For instance, it is a common practice with REST based Web Services to have HTTP GET requests modifying resources on the server side. Whenever that happens however, the access control needs to be properly enforced in the application. No assumptions should be made that only HTTP DELETE, PUT, and POST methods have the power to alter the representation of the resource being accessed in the request.

+ Time of Introduction
  • Architecture and Design
  • Implementation
  • Operation
+ Applicable Platforms

Languages

All

+ Common Consequences
ScopeEffect
Access Control

Technical Impact: Gain privileges / assume identity

An attacker could escalate privileges.

Integrity

Technical Impact: Modify application data

An attacker could modify resources.

Confidentiality

Technical Impact: Read application data

An attacker could obtain sensitive information.

+ Likelihood of Exploit

High

+ Enabling Factors for Exploitation

The application allows HTTP access to resources.

The application is not properly configured to enforce access controls around the resources accessible via HTTP.

+ Observed Examples
ReferenceDescription
The HTTP GET method is designed to retrieve resources and not to alter the state of the application or resources on the server side. However, developers can easily code programs that accept a HTTP GET request that do in fact create, update or delete data on the server. Both Flickr (http://www.flickr.com/services/api/flickr.photosets.delete.html) and del.icio.us (http://del.icio.us/api/posts/delete) have implemented delete operations using standard HTTP GET requests. These HTTP GET methods do delete data on the server side, despite being called from GET, which is not supposed to alter state.
+ Potential Mitigations

Phase: System Configuration

Configure ACLs on the server side to ensure that proper level of access control is defined for each accessible resource representation.

+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfWeakness ClassWeakness Class227Improper Fulfillment of API Contract ('API Abuse')
Development Concepts699
Research Concepts1000
ChildOfWeakness BaseWeakness Base436Interpretation Conflict
Development Concepts (primary)699
Research Concepts (primary)1000
ChildOfCategoryCategory945SFP Secondary Cluster: Insecure Resource Access
Software Fault Pattern (SFP) Clusters (primary)888
+ Content History
Submissions
Submission DateSubmitterOrganizationSource
2008-01-30Evgeny LebanidzeCigitalExternal Submission
Modifications
Modification DateModifierOrganizationSource
2008-09-08CWE Content TeamMITREInternal
updated Common_Consequences, Relationships
2008-10-14CWE Content TeamMITREInternal
updated Description, Enabling_Factors_for_Exploitation
2009-10-29CWE Content TeamMITREInternal
updated Common_Consequences
2011-03-29CWE Content TeamMITREInternal
updated Common_Consequences
2011-06-01CWE Content TeamMITREInternal
updated Common_Consequences
2012-05-11CWE Content TeamMITREInternal
updated Relationships
2012-10-30CWE Content TeamMITREInternal
updated Potential_Mitigations
2014-07-30CWE Content TeamMITREInternal
updated Relationships
2017-01-19CWE Content TeamMITREInternal
updated Relationships

More information is available — Please select a different filter.
Page Last Updated: January 18, 2017