The product receives a request, message, or directive from an upstream component, but the product does not sufficiently preserve the original source of the request before forwarding the request to an external actor that is outside of the product's control sphere. This causes the product to appear to be the source of the request, leading it to act as a proxy or other intermediary between the upstream component and the external actor.

If an attacker cannot directly contact a target, but the product has access to the target, then the attacker can send a request to the product and have it be forwarded to the target. The request would appear to be coming from the product's system, not the attacker's system. As a result, the attacker can bypass access controls (such as firewalls) or hide the source of malicious requests, since the requests would not be coming directly from the attacker.

Since proxy functionality and message-forwarding often serve a legitimate purpose, this issue only becomes a vulnerability when:

• The product runs with different privileges or on a different system, or otherwise has different levels of access than the upstream component;
• The attacker is prevented from making the request directly to the target; and
• The attacker can create a request that the proxy does not explicitly intend to be forwarded on the behalf of the requester. Such a request might point to an unexpected hostname, port number, hardware IP, or service. Or, the request might be sent to an allowed service, but the request could contain disallowed directives, commands, or resources.

Confused Deputy

This weakness is sometimes referred to as the "Confused deputy" problem, in which an attacker misuses the authority of one victim (the "confused deputy") to use that victim's legitimate (restricted) capabilities to target another victim.

This table specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. 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 weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.

Impact	Details
Gain Privileges or Assume Identity; Hide Activities; Execute Unauthorized Code or Commands	Scope: Non-Repudiation, Access Control

Phase(s)	Mitigation
Architecture and Design	Enforce the use of strong mutual authentication mechanism between the two parties.
Architecture and Design	Whenever a product is an intermediary or proxy for transactions between two other components, the proxy core should not drop the identity of the initiator of the transaction. The immutability of the identity of the initiator must be maintained and should be forwarded all the way to the target.

This table shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.

The different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.

Phase	Note
Architecture and Design	REALIZATION: This weakness is caused during implementation of an architectural security tactic.

This listing shows possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.

Languages	Class: Not Language-Specific (Undetermined Prevalence)
Operating Systems	Class: Not OS-Specific (Undetermined Prevalence)
Architectures	Class: Not Architecture-Specific (Undetermined Prevalence)
Technologies	Class: Not Technology-Specific (Undetermined Prevalence)

Example 1

A SoC contains a microcontroller (running ring-3 (least trusted ring) code), a Memory Mapped Input Output (MMIO) mapped IP core (containing design-house secrets), and a Direct Memory Access (DMA) controller, among several other compute elements and peripherals. The SoC implements access control to protect the registers in the IP core (which registers store the design-house secrets) from malicious, ring-3 (least trusted ring) code executing on the microcontroller. The DMA controller, however, is not blocked off from accessing the IP core for functional reasons.

The weakness here is that the intermediary or the proxy agent did not ensure the immutability of the identity of the microcontroller initiating the transaction.

Note: this is a curated list of examples for users to understand the variety of ways in which this weakness can be introduced. It is not a complete list of all CVEs that are related to this CWE entry.

Ordinality	Description
Primary	(where the weakness exists independent of other weaknesses)
Resultant	(where the weakness is typically related to the presence of some other weaknesses)