Home > CAPEC List > CAPEC-58: Restful Privilege Elevation (Version 2.11)  

CAPEC-58: Restful Privilege Elevation

 
Restful Privilege Elevation
Definition in a New Window Definition in a New Window
Attack Pattern ID: 58
Abstraction: Detailed
Status: Draft
Completeness: Complete
Presentation Filter:
+ Summary

Rest uses standard HTTP (Get, Put, Delete) style permissions methods, but these are not necessarily correlated generally with back end programs. Strict interpretation of HTTP get methods means that these HTTP Get services should not be used to delete information on the server, but there is no access control mechanism to back up this logic. This means that unless the services are properly ACL'd and the application's service implementation are following these guidelines then an HTTP request can easily execute a delete or update on the server side.

The attacker identifies a HTTP Get URL such as http://victimsite/updateOrder, which calls out to a program to update orders on a database or other resource. The URL is not idempotent so the request can be submitted multiple times by the attacker, additionally, the attacker may be able to exploit the URL published as a Get method that actually performs updates (instead of merely retrieving data). This may result in malicious or inadvertent altering of data on the server.

+ Attack Prerequisites
  • The attacker needs to be able to identify HTTP Get URLs. The Get methods must be set to call applications that perform operations other than get such as update and delete.

+ Typical Severity

High

+ Typical Likelihood of Exploit

Likelihood: High

+ Methods of Attack
  • Injection
+ Examples-Instances

Description

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.

+ Attacker Skills or Knowledge Required

Skill or Knowledge Level: Low

It is relatively straightforward to identify an HTTP Get method that changes state on the server side and executes against an over-privileged system interface

+ Probing Techniques

Attacker may enumerate URLs to identify vulnerable services.

+ Solutions and Mitigations

Design: Enforce principle of least privilege

Implementation: Ensure that HTTP Get methods only retrieve state and do not alter state on the server side

Implementation: Ensure that HTTP methods have proper ACLs based on what the functionality they expose

+ Attack Motivation-Consequences
ScopeTechnical ImpactNote
Integrity
Modify application data
Confidentiality
Access_Control
Authorization
Gain privileges / assume identity
+ Injection Vector

Payload delivered through standard communication protocols. In the Flickr and del.icio.us examples above, this is done through a normal web browser

+ Payload

Command(s) executed directly on host

+ Activation Zone

Client machine and client network

+ Payload Activation Impact

Enables attacker to execute server side code with any commands that the program owner has privileges to.

+ Purposes
  • Penetration
  • Exploitation
+ CIA Impact
Confidentiality Impact: HighIntegrity Impact: HighAvailability Impact: Low
+ Technical Context
Architectural Paradigms
SOA
Frameworks
All
Platforms
All
Languages
All
+ References
[R.58.1] Mark O'Neill. "Security for REST Web Services". Vprde;. <http://www.vordel.com/downloads/rsa_conf_2006.pdf>.
+ Content History
Submissions
SubmitterOrganizationDateSource
CAPEC Content TeamThe MITRE Corporation2014-06-23Internal_CAPEC_Team
Modifications
ModifierOrganizationDateCommentsSource
CAPEC Content TeamThe MITRE Corporation2015-12-07Updated Related_Attack_PatternsInternal

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Page Last Updated or Reviewed: July 31, 2017