MITRE ATT&CK  /  T1156

T1156

Malicious Shell Modification

Description

Adversaries may establish persistence through executing malicious commands triggered by a user’s shell. User shells execute several configuration scripts at different points throughout the session based on events. For example, when a user opens a command line interface or remotely logs in (such as SSH) a login shell is initiated. The login shell executes scripts from the system (/etc) and the user’s home directory (~/) to configure the environment. All login shells on a system use <code>/etc/profile</code> when initiated. These configuration scripts run at the permission level of their directory and are often used to set environment variables, create aliases, and customize the user’s environment. When the shell exits or terminates, additional shell scripts are executed to ensure the shell exits appropriately.Adversaries may attempt to establish persistence by inserting commands into scripts automatically executed by shells. Using bash as an example, the default shell for most GNU/Linux systems, adversaries may add commands that launch malicious binaries into the <code>/etc/profile</code> and <code>/etc/profile.d</code> files (Citation: intezer-kaiji-malware). These files require root permissions and are executed each time any shell on a system launches. For user level permissions, adversaries can insert malicious commands into <code>~/.bash_profile</code>, <code>~/.bash_login</code>, or <code>~/.profile</code> (Rocke) which are sourced when a user opens a command line inte…

Platforms

Source: MITRE ATT&CK Enterprise matrix. View on attack.mitre.org →