An adversary, through a previously installed malicious application, impersonates an expected or routine task in an attempt to steal sensitive information or leverage a user's privileges. When impersonating an expected task, the adversary monitors the task list maintained by the operating system and waits for a specific legitimate task to become active. Once the task is detected, the malicious application launches a new task in the foreground that mimics the user interface of the legitimate task. At this point, the user thinks that they are interacting with the legitimate task that they started, but instead they are interacting with the malicious application. Once the adversary's goal is reached, the malicious application can exit, leaving the original trusted application visible and the appearance that nothing out of the ordinary has occurred. A second approach entails the adversary impersonating an unexpected task, but one that may often be spawned by legitimate background processes. For example, an adversary may randomly impersonate a system credential prompt, implying that a background process requires authentication for some purpose. The user, believing they are interacting with a legitimate task, enters their credentials or authorizes the use of their stored credentials, which the adversary then leverages for nefarious purposes. This type of attack is most often used to obtain sensitive information (e.g., credentials) from the user, but may also be used to ride the user's privileges.
Likelihood Of Attack
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.
Meta Attack Pattern - A meta level attack pattern in CAPEC is a decidedly abstract characterization of a specific methodology or technique used in an attack. A meta attack pattern is often void of a specific technology or implementation and is meant to provide an understanding of a high level approach. A meta level attack pattern is a generalization of related group of standard level attack patterns. Meta level attack patterns are particularly useful for architecture and design level threat modeling exercises.
Detailed Attack Pattern - A detailed level attack pattern in CAPEC provides a low level of detail, typically leveraging a specific technique and targeting a specific technology, and expresses a complete execution flow. Detailed attack patterns are more specific than meta attack patterns and standard attack patterns and often require a specific protection mechanism to mitigate actual attacks. A detailed level attack pattern often will leverage a number of different standard level attack patterns chained together to accomplish a goal.
Determine suitable tasks to exploit: Determine what tasks exist on the target system that may result in a user providing sensitive information.
Determine what tasks prompt a user for their credentials.
Determine what tasks may prompt a user to authorize a process to execute with elevated privileges.
Impersonate Task: Impersonate a legitimate task, either expected or unexpected, in an attempt to gain user credentials or to ride the user's privileges.
Prompt a user for their credentials, while making the user believe the credential request is legitimate.
Prompt a user to authorize a task to run with elevated privileges, while making the user believe the request is legitimate.
The adversary must already have access to the target system via some means.
A legitimate task must exist that an adversary can impersonate to glean credentials.
The user's privileges allow them to execute certain tasks with elevated privileges.
Once an adversary has gained access to the target system, impersonating a task is trivial.
Malware or some other means to initially comprise the target system.
Additional malware to impersonate a legitimate task.
Credential or permission elevation prompts that appear illegitimate or unexpected.
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.
The only known mitigation to this attack is to avoid installing the malicious application on the device. However, to impersonate a running task the malicious application does need the GET_TASKS permission to be able to query the task list, and being suspicious of applications with that permission can help.
An adversary monitors the system task list for Microsoft Outlook in an attempt to determine when the application may prompt the user to enter their credentials to view encrypted email. Once the task is executed, the adversary impersonates the credential prompt to obtain the user's Microsoft Outlook encryption credentials. These credentials can then be leveraged by the adversary to read a user's encrypted email.
An adversary prompts a user to authorize an elevation of privileges, implying that a background task needs additional permissions to execute. The user accepts the privilege elevation, allowing the adversary to execute additional malware or tasks with the user's privileges.
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.