Adversaries may establish persistence by executing malicious content triggered by an interrupt signal. The <code>trap</code> command allows programs and shells to specify commands that will be executed upon receiving interrupt signals. A common situation is a script allowing for graceful termination and handling of common keyboard interrupts like <code>ctrl+c</code> and <code>ctrl+d</code>.
Adversaries can use this to register code to be executed when the shell encounters specific interrupts as a persistence mechanism. Trap commands are of the following format <code>trap 'command list' signals</code> where "command list" will be executed when "signals" are received.(Citation: Trap Manual)(Citation: Cyberciti Trap Statements)
View in MITRE ATT&CK®| Capability ID | Capability Description | Mapping Type | ATT&CK ID | ATT&CK Name |
|---|---|---|---|---|
| attribute.integrity.variety.Alter behavior | Influence or alter human behavior | related-to | T1546.005 | Event Triggered Execution: Trap |