CAPEC-30

Standard Abstraction Level
Meta — Very abstract, high-level category
Standard — Specific enough to understand
Detailed — Tied to specific technique Draft MITRE CAPEC Status
Stable — Fully reviewed and complete
Draft — Under development
Incomplete — Partially defined
Deprecated — No longer recommended
Obsolete — Replaced by another CAPEC Likelihood: Low Severity: Very High
Hijacking a Privileged Thread of Execution

Description

An adversary hijacks a privileged thread of execution by injecting malicious code into a running process. By using a privleged thread to do their bidding, adversaries can evade process-based detection that would stop an attack that creates a new process. This can lead to an adversary gaining access to the process's memory and can also enable elevated privileges. The most common way to perform this attack is by suspending an existing thread and manipulating its memory.

Prerequisites

The application in question employs a threaded model of execution with the threads operating at, or having the ability to switch to, a higher privilege level than normal users

In order to feasibly execute this class of attacks, the adversary must have the ability to hijack a privileged thread. This ability includes, but is not limited to, modifying environment variables that affect the process the thread belongs to, or calling native OS calls that can suspend and alter process memory. This does not preclude network-based attacks, but makes them conceptually more difficult to identify and execute.

Mitigations

Application Architects must be careful to design callback, signal, and similar asynchronous constructs such that they shed excess privilege prior to handing control to user-written (thus untrusted) code.

Application Architects must be careful to design privileged code blocks such that upon return (successful, failed, or unpredicted) that privilege is shed prior to leaving the block/scope.

Skills Required

[High] Hijacking a thread involves knowledge of how processes and threads function on the target platform, the design of the target application as well as the ability to identify the primitives to be used or manipulated to hijack the thread.