Manipulating User State
Attack Pattern ID: 74 (Standard Attack Pattern Completeness: Complete)Typical Severity: HighStatus: Draft
+ Description

Summary

An attacker modifies state information maintained by the target software in user-accessible locations. If successful, the target software will use this tainted state information and execute in an unintended manner.

State management is an important function within an application. User state maintained by the application can include usernames, payment information, browsing history as well as application-specific contents such as items in a shopping cart.

Manipulating user state can be employed by an attacker to elevate privilege, conduct fraudulent transactions or otherwise modify the flow of the application to derive certain benefits.

Attack Execution Flow

  1. Attacker determines the nature of state management employed by the application. This includes determining the location (client-side, server-side or both) and possibly the items stored as part of user state

  2. The attacker now tries to modify the user state contents (possibly blindly if the contents are encrypted or otherwise obfuscated) and observe the effects of this change on the application.

  3. Having determined the information stored in the user state and the possible ways to modify it, the attacker can violate it in order to perform illegitimate actions.

+ Typical Likelihood of Exploit

Likelihood: Medium

+ Methods of Attack
  • Analysis
  • Modification of Resources
+ Examples-Instances

Description

Upon authenticating a user, an application stores the authentication decision (auth=0/1) in a cookies unencrypted. At every request, this cookie is checked to permit or deny a request.

An attacker can easily violate this representation of user state and set auth=1 at every request in order to gain illegitimate access and elevated privilege in the application.

+ Attacker Skills or Knowledge Required

Skill or Knowledge Level: Medium

The attacker needs to have knowledge of state management as employed by the target application, and also the ability to manipulate the state in a meaningful way.

+ Resources Required

No special resources are required. An attacker can choose to use a data tampering tool to aid in the attack.

+ Probing Techniques

Analysis: The attacker observes contents of client-side user state variables, stored in coookies or hidden fields or query strings, and modifies them in order to observe their effect on the application.

+ Solutions and Mitigations

Do not rely solely on user-controllable locations, such as cookies or URL parameters, to maintain user state

Do not store sensitive information, such as usernames or authentication and authorization information, in user-controllable locations.

At all times sensitive information that is part of the user state must be appropriately protected to ensure confidentiality and integrity at each request

+ Attack Motivation-Consequences
  • Privilege Escalation
  • Data Modification
+ Injection Vector

User-controllable user state variables

+ Payload

Modified or injected user state variables

+ Activation Zone

State management mechanism of the application

+ Payload Activation Impact

Altered user state leading to information leak or elevated privilege

+ Related Weaknesses
CWE-IDWeakness NameWeakness Relationship Type
372Incomplete Internal State DistinctionSecondary
371State IssuesTargeted
315Plaintext Storage in a CookieTargeted
353Failure to Add Integrity Check ValueTargeted
693Protection Mechanism FailureTargeted
+ Related Vulnerabilities
Vulnerability IDRelationship Description
CVE-2005-4448

FlatNuke 2.5.6 verifies authentication credentials based on an MD5 checksum of the admin name and the hashed password rather than the plaintext password, which allows attackers to gain privileges by obtaining the password hash (possibly via CVE-2005-2813), then calculating the credentials and including them in the secid cookie.

+ Related Attack Patterns
NatureTypeIDNameDescriptionView(s) this relationship pertains toView\(s\)
ChildOfCategoryCategory172Time and State Attacks 
Mechanism of Attack (primary)1000
ParentOfAttack PatternAttack Pattern140Bypassing of Intermediate Forms in Multiple-Form Sets 
Mechanism of Attack (primary)1000
+ Relevant Security Requirements

Protect user state that is stored client-side with integrity checks to ensure that a malicious user cannot gain unauthroized access to parts of the application

Authenticate every request to ensure that it is coming from a legitimate user and that the request is a valid one in the current context.

+ Related Security Principles

  • Reluctance To Trust

  • Never Assuming That Your Secrets Are Safe

+ Related Guidelines

  • Treat the Entire Inherited Process Context as Unvalidated Input

  • Use Well-Known Cryptography Appropriately and Correctly

+ Purposes
  • Exploitation
+ CIA Impact
Confidentiality Impact: HighIntegrity Impact: HighAvailability Impact: Medium
+ Technical Context
Architectural Paradigms
Client-Server
SOA
Frameworks
All
Platforms
All
Languages
All
+ Content History
Submissions
SubmitterOrganizationDateComments
Chiradeep B ChhayaCigital, Inc2007-03-08Taken over from Eric Dalci
Modifications
ModifierOrganizationDateComments
Sean BarnumCigital, Inc2007-03-08Review and revise
Richard StruseVOXEM, Inc2007-03-26Review and feedback leading to changes in Name and Description
Sean BarnumCigital, Inc2007-04-16Modified pattern content according to review and feedback
Back to top