T1562.003
Impair Defenses: Impair Command History Logging
Description from ATT&CK
Adversaries may impair command history logging to hide commands they run on a compromised system. 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, 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 HISTCONTROL environment variable keeps track of what should be saved by the history command and eventually into the ~/.bash_history file when a user logs out. HISTCONTROL does not exist by default on macOS, but can be set by the user and will be respected.
Adversaries may clear the history environment variable (unset HISTFILE) or set the command history size to zero (export HISTFILESIZE=0) to prevent logging of commands. Additionally, HISTCONTROL can be configured to ignore commands that start with a space by simply setting it to "ignorespace". HISTCONTROL can also be set to ignore duplicate commands by setting it to "ignoredups". In some Linux systems, this is set by default to "ignoreboth" which covers both of the previous examples. This means that “ ls” will not be saved, but “ls” would be saved by history. Adversaries can abuse this to operate without leaving traces by simply prepending a space to all of their terminal commands.
On Windows systems, the PSReadLine module tracks commands used in all PowerShell sessions and writes them to a file ($env:APPDATA\Microsoft\Windows\PowerShell\PSReadLine\ConsoleHost_history.txt by default). Adversaries may change where these logs are saved using Set-PSReadLineOption -HistorySavePath {File Path}. This will cause ConsoleHost_history.txt to stop receiving logs. Additionally, it is possible to turn off logging to this file using the PowerShell command Set-PSReadlineOption -HistorySaveStyle SaveNothing.(Citation: Microsoft PowerShell Command History)(Citation: Sophos PowerShell command audit)(Citation: Sophos PowerShell Command History Forensics)
Adversaries may also leverage a Network Device CLI on network devices to disable historical command logging (e.g. no logging).
Atomic Tests
Atomic Test #1 - Disable history collection
Disables history collection in shells
Supported Platforms: linux,macos
auto_generated_guid: 4eafdb45-0f79-4d66-aa86-a3e2c08791f5
Inputs:
Name | Description | Type | Default Value |
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evil_command | Command to run after shell history collection is disabled | string | whoami |
Attack Commands: Run with sh!
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export HISTCONTROL=ignoreboth
#{evil_command}
Atomic Test #2 - Disable history collection (freebsd)
Disables history collection in shells
Supported Platforms: linux
auto_generated_guid: cada55b4-8251-4c60-819e-8ec1b33c9306
Inputs:
Name | Description | Type | Default Value |
---|---|---|---|
evil_command | Command to run after shell history collection is disabled | string | whoami |
Attack Commands: Run with sh!
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export HISTSIZE=0
#{evil_command}
Atomic Test #3 - Mac HISTCONTROL
The HISTCONTROL variable is set to ignore (not write to the history file) command that are a duplicate of something already in the history and commands that start with a space. This atomic sets this variable in the current session and also writes it to the current user's ~/.bash_profile so that it will apply to all future settings as well. https://www.linuxjournal.com/content/using-bash-history-more-efficiently-histcontrol
Supported Platforms: macos,linux
auto_generated_guid: 468566d5-83e5-40c1-b338-511e1659628d
Inputs:
None
Run it with these steps!
- export HISTCONTROL=ignoreboth
- echo export "HISTCONTROL=ignoreboth" >> ~/.bash_profile
- ls
- whoami > recon.txt
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Atomic Test #4 - Clear bash history
An attacker may clear the bash history cache and the history file as their last act before logging off to remove the record of their command line activities.
In this test we use the $HISTFILE variable throughout to 1. confirms the $HISTFILE variable is set 2. echo "" into it 3..5 confirm the file is empty 6 clear the history cache 7. confirm the history cache is empty. This is when the attacker would logoff.
Supported Platforms: linux
auto_generated_guid: 878794f7-c511-4199-a950-8c28b3ed8e5b
Inputs:
None
Attack Commands: Run with bash!
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cp $HISTFILE $HISTFILE.OLD
if ((${#HISTFILE[@]})); then echo $HISTFILE; fi
echo "" > $HISTFILE
if [ $(wc -c <$HISTFILE) -gt 1 ]; then echo "$HISTFILE is larger than 1k"; fi
ls -la $HISTFILE
cat $HISTFILE
history -c
if [ $(history |wc -l) -eq 1 ]; then echo "History cache cleared"; fi
Cleanup Commands:
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mv -f $HISTFILE.OLD $HISTFILE
Atomic Test #5 - Setting the HISTCONTROL environment variable
An attacker may exploit the space before a command (e.g. " ls") or the duplicate command suppression feature in Bash history to prevent their commands from being recorded in the history file or to obscure the order of commands used.
In this test we 1. sets $HISTCONTROL to ignoreboth 2. clears the history cache 3. executes ls -la with a space in-front of it 4. confirms that ls -la is not in the history cache 5. sets $HISTCONTROL to erasedups 6. clears the history cache 7..9 executes ls -la $HISTFILE 3 times 10. confirms that their is only one command in history
Supported Platforms: linux
auto_generated_guid: 10ab786a-028e-4465-96f6-9e83ca6c5f24
Inputs:
None
Attack Commands: Run with bash!
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TEST=$(echo $HISTCONTROL)
if [ "$HISTCONTROL" != "ignoreboth" ]; then export HISTCONTROL="ignoreboth"; fi
history -c
ls -la $HISTFILE # " ls -la $HISTFILE"
if [ $(history |wc -l) -eq 1 ]; then echo "ls -la is not in history cache"; fi
# -> ls -la is not in history cache
if [ "$HISTCONTROL" != "erasedups" ]; then export HISTCONTROL="erasedups"; fi
history -c
ls -la $HISTFILE
ls -la $HISTFILE
ls -la $HISTFILE
if [ $(history |wc -l) -eq 2 ]; then echo "Their is only one entry for ls -la $HISTFILE"; fi
Cleanup Commands:
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export HISTCONTROL=$(echo $TEST)
Atomic Test #6 - Setting the HISTFILESIZE environment variable
An Adversary may set the bash history files size environment variable (HISTFILESIZE) to zero to prevent the logging of commands to the history file after they log out of the system.
Note: we don't wish to log out, so we are just confirming the value of HISTFILESIZE. In this test we 1. echo HISTFILESIZE 2. set it to zero 3. confirm that HISTFILESIZE is set to zero.
Supported Platforms: linux
auto_generated_guid: 5cafd6c1-2f43-46eb-ac47-a5301ba0a618
Inputs:
None
Attack Commands: Run with bash!
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TEST=$(echo $HISTFILESIZE)
echo $HISTFILESIZE
export HISTFILESIZE=0
if [ $(echo $HISTFILESIZE) -eq 0 ]; then echo "\$HISTFILESIZE is zero"; fi
# -> $HISTFILESIZE is zero
Cleanup Commands:
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export HISTCONTROL=$(echo $TEST)
Atomic Test #7 - Setting the HISTSIZE environment variable
An Adversary may set the sh history files size environment variable (HISTSIZE) to zero to prevent the logging of commands to the history file after they log out of the system.
Note: we don't wish to log out, so we are just confirming the value of HISTSIZE. In this test we 1. echo HISTSIZE 2. set it to zero 3. confirm that HISTSIZE is set to zero.
Supported Platforms: linux
auto_generated_guid: 386d3850-2ce7-4508-b56b-c0558922c814
Inputs:
None
Attack Commands: Run with sh!
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echo $HISTSIZE
export HISTSIZE=0
if [ $(echo $HISTSIZE) -eq 0 ]; then echo "\$HISTSIZE is zero"; fi
# -> $HISTSIZE is zero
Cleanup Commands:
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export HISTSIZE=100
Atomic Test #8 - Setting the HISTFILE environment variable
An Adversary may clear, unset or redirect the history environment variable HISTFILE to prevent logging of commands to the history file after they log out of the system.
Note: we don't wish to log out, so we are just confirming the value of HISTFILE. In this test we 1. echo HISTFILE 2. set it to /dev/null 3. confirm that HISTFILE is set to /dev/null.
Supported Platforms: linux
auto_generated_guid: b3dacb6c-a9e3-44ec-bf87-38db60c5cad1
Inputs:
None
Attack Commands: Run with bash!
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TEST=$(echo $HISTFILE)
echo $HISTFILE
export HISTFILE="/dev/null"
if [ $(echo $HISTFILE) == "/dev/null" ]; then echo "\$HISTFILE is /dev/null"; fi
# -> $HISTFILE is /dev/null
Cleanup Commands:
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export HISTFILE=$(echo $TEST)
Atomic Test #9 - Setting the HISTFILE environment variable (freebsd)
An Adversary may clear, unset or redirect the history environment variable HISTFILE to prevent logging of commands to the history file after they log out of the system.
Note: we don't wish to log out, so we are just confirming the value of HISTFILE. In this test we 1. echo HISTFILE 2. set it to /dev/null 3. confirm that HISTFILE is set to /dev/null.
Supported Platforms: linux
auto_generated_guid: f7308845-6da8-468e-99f2-4271f2f5bb67
Inputs:
None
Attack Commands: Run with sh!
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echo $HISTFILE
export HISTFILE="/dev/null"
if [ $(echo $HISTFILE) == "/dev/null" ]; then echo "\$HISTFILE is /dev/null"; fi
# -> $HISTFILE is /dev/null
Cleanup Commands:
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export HISTFILE=~/.sh_history
Atomic Test #10 - Setting the HISTIGNORE environment variable
An Adversary may take advantage of the HISTIGNORE environment variable either to ignore particular commands or all commands.
In this test we 1. set HISTIGNORE to ignore ls, rm and ssh commands 2. clear this history cache 3..4 execute ls commands 5. confirm that the ls commands are not in the history cache 6. unset HISTIGNORE variable 7.. same again, but ignoring ALL commands.
Supported Platforms: linux
auto_generated_guid: f12acddb-7502-4ce6-a146-5b62c59592f1
Inputs:
None
Attack Commands: Run with bash!
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if ((${#HISTIGNORE[@]})); then echo "\$HISTIGNORE = $HISTIGNORE"; else export HISTIGNORE='ls*:rm*:ssh*'; echo "\$HISTIGNORE = $HISTIGNORE"; fi
history -c
ls -la $HISTFILE
ls -la ~/.bash_logout
if [ $(history |wc -l) -eq 1 ]; then echo "ls commands are not in history"; fi
unset HISTIGNORE
if ((${#HISTIGNORE[@]})); then echo "\$HISTIGNORE = $HISTIGNORE"; else export HISTIGNORE='*'; echo "\$HISTIGNORE = $HISTIGNORE"; fi
history -c
whoami
groups
if [ $(history |wc -l) -eq 0 ]; then echo "History cache is empty"; fi
Cleanup Commands:
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unset HISTIGNORE
Atomic Test #11 - Disable Windows Command Line Auditing using reg.exe
In Windows operating systems, command line auditing is controlled through the following registry value:
Registry Path: HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\Audit
Registry Value: ProcessCreationIncludeCmdLine_Enabled
When command line auditing is enabled, the system records detailed information about command execution, including the command executed, the user account responsible for executing the command, and the timestamp of the execution. This information is crucial for security monitoring and forensic analysis, as it helps organizations detect and investigate unauthorized or malicious activities within their systems. By default, command line auditing may not be enabled in Windows systems, and administrators must manually configure the appropriate registry settings to activate it. Conversely, attackers may attempt to tamper with these registry keys to disable command line auditing, as part of their efforts to evade detection and cover their tracks while perpetrating malicious activities.
Because this attack executes reg.exe using a command prompt, this attack can be detected by monitoring both: Process Creation events for reg.exe (Windows Event ID 4688, Sysmon Event ID 1) Registry events (Windows Event ID 4657, Sysmon Event ID 13)
Read more here: https://securitydatasets.com/notebooks/atomic/windows/defense_evasion/SDWIN-220703123711.html
Supported Platforms: windows
auto_generated_guid: 1329d5ab-e10e-4e5e-93d1-4d907eb656e5
Inputs:
None
Attack Commands: Run with command_prompt! Elevation Required (e.g. root or admin)
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reg add HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\Audit /v ProcessCreationIncludeCmdLine_Enabled /t REG_DWORD /d 0 /f
Cleanup Commands:
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reg add HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\Audit /v ProcessCreationIncludeCmdLine_Enabled /t REG_DWORD /d 1 /f
Atomic Test #12 - Disable Windows Command Line Auditing using Powershell Cmdlet
In Windows operating systems, command line auditing is controlled through the following registry value:
Registry Path: HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\Audit
Registry Value: ProcessCreationIncludeCmdLine_Enabled
When command line auditing is enabled, the system records detailed information about command execution, including the command executed, the user account responsible for executing the command, and the timestamp of the execution. This information is crucial for security monitoring and forensic analysis, as it helps organizations detect and investigate unauthorized or malicious activities within their systems. By default, command line auditing may not be enabled in Windows systems, and administrators must manually configure the appropriate registry settings to activate it. Conversely, attackers may attempt to tamper with these registry keys to disable command line auditing, as part of their efforts to evade detection and cover their tracks while perpetrating malicious activities.
Because this attack runs a Powershell cmdlet, this attack can be detected by monitoring both: Powershell Logging (Windows Powershell Event ID 400, 800, 4103, 4104) Registry events (Windows Event ID 4657, Sysmon Event ID 13)
Read more here: https://securitydatasets.com/notebooks/atomic/windows/defense_evasion/SDWIN-220703123711.html https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.management/new-itemproperty?view=powershell-7.4#example-2-add-a-registry-entry-to-a-key
Supported Platforms: windows
auto_generated_guid: 95f5c72f-6dfe-45f3-a8c1-d8faa07176fa
Inputs:
None
Attack Commands: Run with powershell! Elevation Required (e.g. root or admin)
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New-ItemProperty -Path "HKLM:Software\Microsoft\Windows\CurrentVersion\Policies\System\Audit" -Name "ProcessCreationIncludeCmdLine_Enabled" -Value 0 -PropertyType DWORD -Force -ErrorAction Ignore
Cleanup Commands:
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New-ItemProperty -Path "HKLM:Software\Microsoft\Windows\CurrentVersion\Policies\System\Audit" -Name "ProcessCreationIncludeCmdLine_Enabled" -Value 1 -PropertyType DWORD -Force -ErrorAction Ignore