The adversary modifies state information maintained by the target software or causes a state transition in hardware. If successful, the target will use this tainted state and execute in an unintended manner.
State management is an important function within a software 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 adversary to elevate privilege, conduct fraudulent transactions or otherwise modify the flow of the application to derive certain benefits.
If there is a hardware logic error in a finite state machine, the adversary can use this to put the system in an undefined state which could cause a denial of service or exposure of secure data.
Likelihood Of Attack
Medium
Typical Severity
High
Relationships
This table shows the other attack patterns and high level categories that are related to this attack pattern. These relationships are defined as ChildOf and ParentOf, and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as CanFollow, PeerOf, and CanAlsoBe are defined to show similar attack patterns that the user may want to explore.
Nature
Type
ID
Name
ParentOf
Standard Attack Pattern - A standard level attack pattern in CAPEC is focused on a specific methodology or technique used in an attack. It is often seen as a singular piece of a fully executed attack. A standard attack pattern is meant to provide sufficient details to understand the specific technique and how it attempts to accomplish a desired goal. A standard level attack pattern is a specific type of a more abstract meta level attack pattern.
Adversary determines the nature of state management employed by the target. This includes determining the location (client-side, server-side or both applications) and possibly the items stored as part of user state.
Experiment
The adversary now tries to modify the user state contents (possibly blindly if the contents are encrypted or otherwise obfuscated) or cause a state transition and observe the effects of this change on the target.
Exploit
Having determined how to manipulate the state, the adversary can perform illegitimate actions.
Prerequisites
User state is maintained at least in some way in user-controllable locations, such as cookies or URL parameters.
There is a faulty finite state machine in the hardware logic that can be exploited.
Skills Required
[Level: Medium]
The adversary 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
The adversary needs a data tampering tool capable of generating and creating custom inputs to aid in the attack, like Fiddler, Wireshark, or a similar in-browser plugin (e.g., Tamper Data for Firefox).
Consequences
This table specifies different individual consequences associated with the attack pattern. The Scope identifies the security property that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in their attack. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a pattern will be used to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.
Scope
Impact
Likelihood
Confidentiality
Access Control
Authorization
Gain Privileges
Integrity
Modify Data
Availability
Unreliable Execution
Mitigations
Do not rely solely on user-controllable locations, such as cookies or URL parameters, to maintain user state.
Avoid sensitive information, such as usernames or authentication and authorization information, in user-controllable locations.
Sensitive information that is part of the user state must be appropriately protected to ensure confidentiality and integrity at each request.
All possible states must be handled by hardware finite state machines.
Example Instances
During the authentication process, an application stores the authentication decision (auth=0/1) in unencrypted cookies. At every request, this cookie is checked to permit or deny a request.
An adversary 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.
Related Weaknesses
A Related Weakness relationship associates a weakness with this attack pattern. Each association implies a weakness that must exist for a given attack to be successful. If multiple weaknesses are associated with the attack pattern, then any of the weaknesses (but not necessarily all) may be present for the attack to be successful. Each related weakness is identified by a CWE identifier.
Description
This table shows the other attack patterns and high level categories that are related to this attack pattern. These relationships are defined as ChildOf and ParentOf, and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as CanFollow, PeerOf, and CanAlsoBe are defined to show similar attack patterns that the user may want to explore.
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