Sub-technique of T1070 Indicator Removal.View on attack.mitre.org
In addition to clearing system logs, an adversary may clear the command history of a compromised account to conceal the actions undertaken during an intrusion. Various command interpreters keep track of the commands users type in their terminal so that users can retrace what they've done.
On Linux and macOS, these command histories can be accessed in a few different ways. While logged in, this command history is tracked in a file pointed to by the environment variable HISTFILE. When a user logs off a system, this information is flushed to a file in the user's home directory called ~/.bash_history. The benefit of this is that it allows users to go back to commands they've used before in different sessions. Adversaries may delete their commands from these logs by manually clearing the history (history -c) or deleting the bash history file rm ~/.bash_history.
Adversaries may also leverage a Network Device CLI on network devices to clear command history data (clear logging and/or clear history). On ESXi servers, command history may be manually removed from the `/var/log/shell.log` file.
On Windows hosts, PowerShell has two different command history providers: the built-in history and the command history managed by the PSReadLine module. The built-in history only tracks the commands used in the current session. This command history is not available to other sessions and is deleted when the session ends.
The PSReadLine command history tracks the commands used in all PowerShell sessions and writes them to a file ($env:APPDATA\Microsoft\Windows\PowerShell\PSReadLine\ConsoleHost_history.txt by default). This history file is available to all sessions and contains all past history since the file is not deleted when the session ends.
Adversaries may run the PowerShell command Clear-History to flush the entire command history from a current PowerShell session. This, however, will not delete/flush the ConsoleHost_history.txt file. Adversaries may also delete the ConsoleHost_history.txt file or edit its contents to hide PowerShell commands they have run.
Rules on DetectionCode tagged with T1070.003.
| Rule | Level | Log source |
|---|---|---|
| Cisco Clear Logs | high | cisco / NULL |
| Clearing Windows Console History | high | windows / ps_script |
| Disable Powershell Command History | high | windows / ps_script |
| Linux Command History Tampering | high | linux / NULL |
| RunMRU Registry Key Deletion | high | windows / process_creation |
| RunMRU Registry Key Deletion - Registry | high | windows / registry_delete |
| Clear PowerShell History - PowerShell | medium | windows / ps_script |
| Clear PowerShell History - PowerShell Module | medium | windows / ps_module |
| Suspicious IO.FileStream | medium | windows / ps_script |
| Rule | Type | Risk | Data source |
|---|---|---|---|
| Windows ConsoleHost History File Deletion | Anomaly | NULL | Sysmon EventID 23, Sysmon EventID 26 |
| Windows Powershell History File Deletion | Anomaly | NULL | Powershell Script Block Logging 4104 |
None recorded.
| Used by | Procedure example |
|---|---|
| GroupAPT41 | APT41 attempted to remove evidence of some of its activity by deleting Bash histories. |
| GroupAPT5 | APT5 has cleared the command history on targeted ESXi servers. |
| GroupAquatic Panda | Aquatic Panda cleared command history in Linux environments to remove traces of activity after operations. |
| GroupLazarus Group | Lazarus Group has routinely deleted log files on a compromised router, including automatic log deletion through the use of the logrotate utility. |
| GroupMagic Hound | Magic Hound has removed mailbox export requests from compromised Exchange servers. |
| GroupMedusa Group | Medusa Group has cleared command history by running the PowerShell command `Remove-Item (Get-PSReadlineOption).HistorySavePath`. |
| GroupmenuPass | menuPass has used Wevtutil to remove PowerShell execution logs. |
| GroupTeamTNT | TeamTNT has cleared command history with |
Data from MITRE ATT&CK® (Enterprise). ATT&CK® is a registered trademark of The MITRE Corporation.
