CyLR — Live Response Collection tool by Alan Orlikoski and Jason Yegge

Open Letter to the users of Skadi, CyLR, and CDQR

• OSDFCON 2017 Slides: Walk-through different techniques that are required to provide forensics results for Windows and *nix environments (Including CyLR and CDQR)

The CyLR tool collects forensic artifacts from hosts with NTFS file systems quickly, securely and minimizes impact to the host.

The main features are:

• Quick collection (it's really fast)
• Raw file collection process does not use Windows API
• Collection of key artifacts by default.
• Ability to specify custom targets for collection.
• Acquisition of special and in-use files, including alternate data streams, system files, and hidden files.
• Glob and regular expression patterns are available to specify custom targets.
• Data is collected into a zip file, allowing the user to modify the compression level, set an archive password, and file name.
• Specification of a SFTP destination for the file archive.

CyLR uses .NET Core and runs natively on Windows, Linux, and MacOS. Self contained applications for the following are included in releases for version 2.0 and higher.

• Windows x86
• Windows x64
• Linux x64
• MacOS x64

Below is the output of CyLR:

$ CyLR -h
CyLR Version 2.2.0.0

Usage: CyLR [Options]... [Files]...

The CyLR tool collects forensic artifacts from hosts with NTFS file systems
quickly, securely and minimizes impact to the host.

The available options are:
-od
        Defines the directory that the zip archive will be created in.
        Defaults to current working directory.
        Usage: -od <directory path>
-of
        Defines the name of the zip archive will be created. Defaults to
        host machine's name.
        Usage: -of <archive name>
-c
        Optional argument to provide custom list of artifact files and
        directories (one entry per line). NOTE: Please see
        CUSTOM_PATH_TEMPLATE.txt for sample.
        Usage: -c <path to config file>
-d
        Same as '-c' but will collect default paths included in CyLR in
        addition to those specified in the provided config file.
        Usage: -d <path to config file>
-u
        SFTP username
        Usage: -u <sftp-username>
-p
        SFTP password
        Usage: -p <password>
-s
        SFTP Server resolvable hostname or IP address and port. If no port
        is given then 22 is used by default.  Format is <server name>:<port>
        Usage: -s <ip>:<port>
-os
        Defines the output directory on the SFTP server, as it may be a
        different location than the ZIP generate on disk. Can be full or
        relative path.
        Usage: -os <directory path>
-zp
        If specified, the resulting zip file will be password protected
        with this password.
        Usage: -zp <password>
-zl
        Uses a number between 1-9 to change the compression level
        of the archive file. Defaults to 3
        Usage: -zl <0-9>
--no-sftpcleanup
        Disables the removal of the .zip file used for collection after
        uploading to the SFTP server. Only applies if SFTP option is enabled.
        Usage: --no-sftpcleanup
--dry-run
        Collect artifacts to a virtual zip archive, but does not send
        or write to disk.
--force-native
        Uses the native file system instead of a raw NTFS read. Unix-like
        environments always use this option.
--usnjrnl
        Enables collecting $UsnJrnl
-l
        Sets the file path to write log messages to. Defaults to ./CyLR.log
        Usage: -l CyLR_run.log
-q
        Disables logging to the console and file.
        Usage: -q
-v
        Increases verbosity of the console log. By default the console
        only shows information or greater events and the file log shows
        all entries. Disabled when `-q` is used.
        Usage: -v

CyLR tool collects forensic artifacts from hosts with NTFS file systems quickly, securely and minimizes impact to the host. All collection paths are case-insensitive.

Note: See CollectionPaths.cs for a full list of default files collected and for the underlying patterns used for collection. You can easily extend this list through the use of patterns as shown in CUSTOM_PATH_TEMPLATE.txt or by opening a pull request.

The standard list of collected artifacts are as follows.

System Root (ie C:\Windows):

• %SYSTEMROOT%\Tasks\**
• %SYSTEMROOT%\Prefetch\**
• %SYSTEMROOT%\System32\sru\**
• %SYSTEMROOT%\System32\winevt\Logs\**
• %SYSTEMROOT%\System32\Tasks\**
• %SYSTEMROOT%\System32\Logfiles\W3SVC1\**
• %SYSTEMROOT%\Appcompat\Programs\**
• %SYSTEMROOT%\SchedLgU.txt
• %SYSTEMROOT%\inf\setupapi.dev.log
• %SYSTEMROOT%\System32\drivers\etc\hosts
• %SYSTEMROOT%\System32\config\SAM
• %SYSTEMROOT%\System32\config\SOFTWARE
• %SYSTEMROOT%\System32\config\SECURITY
• %SYSTEMROOT%\System32\config\SOFTWARE
• %SYSTEMROOT%\System32\config\SAM.LOG1
• %SYSTEMROOT%\System32\config\SOFTWARE.LOG1
• %SYSTEMROOT%\System32\config\SECURITY.LOG1
• %SYSTEMROOT%\System32\config\SOFTWARE.LOG1
• %SYSTEMROOT%\System32\config\SAM.LOG2
• %SYSTEMROOT%\System32\config\SOFTWARE.LOG2
• %SYSTEMROOT%\System32\config\SECURITY.LOG2
• %SYSTEMROOT%\System32\config\SOFTWARE.LOG2

Program Data (ie C:\ProgramData):

• %PROGRAMDATA%\Microsoft\Windows\Start Menu\Programs\Startup\**

Drive Root (ie C:\)

• %SYSTEMDRIVE%\$Recycle.Bin\**\$I*
• %SYSTEMDRIVE%\$Recycle.Bin\$I*
• %SYSTEMDRIVE%\$LogFile
• %SYSTEMDRIVE%\$MFT

User Profiles (ie C:\Users\*):

• C:\Users\*\NTUser.DAT
• C:\Users\*\NTUser.DAT.LOG1
• C:\Users\*\NTUser.DAT.LOG2
• C:\Users\*\AppData\Roaming\Microsoft\Windows\Recent\**
• C:\Users\*\AppData\Roaming\Microsoft\Windows\PowerShell\PSReadline\ConsoleHost_history.txt
• C:\Users\*\AppData\Roaming\Mozilla\Firefox\Profiles\**
• C:\Users\*\AppData\Local\Microsoft\Windows\WebCache\**
• C:\Users\*\AppData\Local\Microsoft\Windows\Explorer\**
• C:\Users\*\AppData\Local\Microsoft\Windows\UsrClass.dat
• C:\Users\*\AppData\Local\Microsoft\Windows\UsrClass.dat.LOG1
• C:\Users\*\AppData\Local\Microsoft\Windows\UsrClass.dat.LOG2
• C:\Users\*\AppData\Local\ConnectedDevicesPlatform\**
• C:\Users\*\AppData\Local\Google\Chrome\User Data\Default\History\**
• C:\Users\*\AppData\Local\Microsoft\Edge\User Data\Default\History\**

Note: Modern macOS systems have functionality that will prompt the user to approve on a per-application basis, access to sensitive locations on a system. This can be overridden through modifying the System Preferences to give the CyLR binary and it's parent process (such as Terminal) full disk access.

System paths:

• /etc/hosts.allow
• /etc/hosts.deny
• /etc/hosts
• /etc/passwd
• /etc/group
• /etc/rc.d/**
• /var/log/**
• /private/etc/rc.d/**
• /private/etc/hosts.allow
• /private/etc/hosts.deny
• /private/etc/hosts
• /private/etc/passwd
• /private/etc/group
• /private/var/log/**
• /System/Library/StartupItems/**
• /System/Library/LaunchAgents/**
• /System/Library/LaunchDaemons/**
• /Library/StartupItems/**
• /Library/LaunchAgents/**
• /Library/LaunchDaemons/**
• /.fseventsd/**

Libraries paths:

• **/Library/*Support/Google/Chrome/Default/*
• **/Library/*Support/Google/Chrome/Default/History*
• **/Library/*Support/Google/Chrome/Default/Cookies*
• **/Library/*Support/Google/Chrome/Default/Bookmarks*
• **/Library/*Support/Google/Chrome/Default/Extensions/**
• **/Library/*Support/Google/Chrome/Default/Extensions/Last*
• **/Library/*Support/Google/Chrome/Default/Extensions/Shortcuts*
• **/Library/*Support/Google/Chrome/Default/Extensions/Top*
• **/Library/*Support/Google/Chrome/Default/Extensions/Visited*

User paths:

• /root/.*history
• /Users/*/.*history

Other Paths:

• **/places.sqlite*
• **/downloads.sqlite*

System Paths:

• /etc/hosts.allow
• /etc/hosts.deny
• /etc/hosts
• /etc/passwd
• /etc/group
• /etc/crontab
• /etc/cron.allow
• /etc/cron.deny
• /etc/anacrontab
• /etc/apt/sources.list
• /etc/apt/trusted.gpg
• /etc/apt/trustdb.gpg
• /etc/resolv.conf
• /etc/fstab
• /etc/issues
• /etc/issues.net
• /etc/insserv.conf
• /etc/localtime
• /etc/timezone
• /etc/pam.conf
• /etc/rsyslog.conf
• /etc/xinetd.conf
• /etc/netgroup
• /etc/nsswitch.conf
• /etc/ntp.conf
• /etc/yum.conf
• /etc/chrony.conf
• /etc/chrony
• /etc/sudoers
• /etc/logrotate.conf
• /etc/environment
• /etc/hostname
• /etc/host.conf
• /etc/fstab
• /etc/machine-id
• /etc/screen-rc
• /etc/rc.d/**
• /etc/cron.daily/**
• /etc/cron.hourly/**
• /etc/cron.weekly/**
• /etc/cron.monthly/**
• /etc/modprobe.d/**
• /etc/modprobe-load.d/**
• /etc/*-release
• /etc/pam.d/**
• /etc/rsyslog.d/**
• /etc/yum.repos.d/**
• /etc/init.d/**
• /etc/systemd.d/**
• /etc/default/**
• /var/log/**
• /var/spool/at/**
• /var/spool/cron/**
• /var/spool/anacron/cron.daily
• /var/spool/anacron/cron.hourly
• /var/spool/anacron/cron.weekly
• /var/spool/anacron/cron.monthly
• /boot/grub/grub.cfg
• /boot/grub2/grub.cfg
• /sys/firmware/acpi/tables/DSDT

User paths:

• /root/.*history
• /root/.*rc
• /root/.*_logout
• /root/.ssh/config
• /root/.ssh/known_hosts
• /root/.ssh/authorized_keys
• /root/.selected_editor
• /root/.viminfo
• /root/.lesshist
• /root/.profile
• /root/.selected_editor
• /home/*/.*history
• /home/*/.ssh/known_hosts
• /home/*/.ssh/config
• /home/*/.ssh/autorized_keys
• /home/*/.viminfo
• /home/*/.profile
• /home/*/.*rc
• /home/*/.*_logout
• /home/*/.selected_editor
• /home/*/.wget-hsts
• /home/*/.gitconfig
• /home/*/.mozilla/firefox/*.default*/**/*.sqlite*
• /home/*/.mozilla/firefox/*.default*/**/*.json
• /home/*/.mozilla/firefox/*.default*/**/*.txt
• /home/*/.mozilla/firefox/*.default*/**/*.db*
• /home/*/.config/google-chrome/Default/History*
• /home/*/.config/google-chrome/Default/Cookies*
• /home/*/.config/google-chrome/Default/Bookmarks*
• /home/*/.config/google-chrome/Default/Extensions/**
• /home/*/.config/google-chrome/Default/Last*
• /home/*/.config/google-chrome/Default/Shortcuts*
• /home/*/.config/google-chrome/Default/Top*
• /home/*/.config/google-chrome/Default/Visited*
• /home/*/.config/google-chrome/Default/Preferences*
• /home/*/.config/google-chrome/Default/Login Data*
• /home/*/.config/google-chrome/Default/Web Data*

In general: some kind of administrative rights on the target (root, sudo, administrator,...).

CyLR now uses .NET Core and now runs natively on Windows, Linux, and MacOS as a .NET Core app or a self contained executable through the warp packer As a note, the package script will download the warp packer to generate a single binary with the CyLR resources and full CLR runtime for portability. This means that the binary will unpack in a temporary location for execution. According to the warp documentation, these locations are:

Packages cache location:

• Linux: $HOME/.local/share/warp/packages
• macOS: $HOME/Library/Application Support/warp/packages
• Windows: %LOCALAPPDATA%\warp\packages

Runners cache location:

• Linux: $HOME/.local/share/warp/runners
• macOS: $HOME/Library/Application Support/warp/runners
• Windows: %LOCALAPPDATA%\warp\runners

These caches are only created on first execution or when the packed binary is updated.

CyLR.exe

./CyLR

CyLR.exe -od "C:\Temp\LRData"

CyLR.exe -od LRData

CyLR.exe -q

CyLR.exe -u username -p password -s 8.8.8.8

CyLR -od data -of important-data.zip

CyLR --usnjrnl

The sample custom.txt, requires a tab delimiter between pattern definition and pattern. Lines starting with # will be ignored:

# Static paths are fixed, case-insensitive paths to compare
# against files found on a system. This is the fastest search
# method available, please use when possible.
#
static  C:\Windows\System32\Config\SAM
#
# Glob paths leverage glob patterns specified at
# `https://github.com/dazinator/DotNet.Glob`. This is faster than RegEx and
# should be favored unless more complex patterns are required. Useful for
# scanning for files by name or extension recursively. Also useful for
# collecting a folder recursively.
#
glob    **\malware.exe
#
# Regex paths leverage the .NET Regex capabilities and will search for
# specified patterns across accessible files. This is the slowest option and
# should be saved for unique use cases that are not supported by globbing.
#
regex   .*\Windows\Temp\[a-z]{8}\+*

This can then be supplied to CyLR for a custom collection of just these paths:

CyLR.exe -c custom.txt

CyLR -d custom.txt

CyLR allows for the specification of custom collection paths with the use of a configuration file provided after -c or -d at the command line. A brief summary of the format is below, though full details are available within the CUSTOM_PATH_TEMPLATE.txt provided in the repository.

The custom collection path file allows for the specification of files to collect from a target system. The format is tab delimited, where the first field is a pattern type indicator and the second field is the pattern to collect.

• NOTE: As previously mentioned, all collection paths are case-insensitive.
• NOTE: The path specifier needs to match the platform you are collecting from. For Windows, it must be \ and / for macOS and Linux.
• NOTE: You must use tabs to delimit the patterns. Spaces will not work. This means that spaces are allowed in the second field containing pattern content

There are 4 pattern types, summarized below:

• static
  • This format allows for the specification of a specific file at a known path.
  • This is the fastest pattern type, as it is performing a string comparison.
  • Example: static C:\Windows\System32\config\SAM
• glob
  • This format allows the specification of basic patterns. Most commonly used to collect the contents of a folder, even recursively. Has a few common implementations, demonstrated in the examples below.
  • While not as fast as static paths, it allows for some common pattern matching and is faster than leveraging regular expressions.
  • Example: glob C:\Users\*\ntuser.dat - collects the NTUser.dat from each user.
  • Example: glob C:\**\malware.exe - collects files named malware.exe regardless of what folder they are in, recursively.
  • Example: glob C:\Users\*\AppData\Microsoft\Windows\Recent\*.lnk - collects all files ending with .lnk
  • Example: glob **\*malware* - collects all files recursively.
  • More details at github.com/dazinator/DotNet.Glob
• regex
  • Allows the specification of advanced patterns through .NET's regular expression implementation.
  • Example: regex C:\[0-9]+.exe - collect all numeric-only executables in the root of the C:\ drive.
• force
  • Same as the static option, though will attempt collection even if the file is not identified in the file enumeration process.
  • This is useful in the collection of alternate data streams and special files not generally exposed to directory traversal functions.
  • Example: force C:\$Extend\$UsnJrnl:$J

CyLR binaries are available for download, prebuilt for use on macOS, Linux, and Windows operating systems. The following operating systems were tested against:

• Windows 10, build 1909
• macOS 10.14.16
• Debian 10
• Ubuntu 18.04
• CentOS 8.1
• RedHat 8.1

To build CyLR yourself, follow the below steps:

1. Install dotnet core on your platform
2. Clone this repository
3. Run the following scripts in order:
   1. Linux/macOS: ./scripts/test.sh or Windows: .\scripts\test_win.ps1
   2. Linux/macOS: ./scripts/build.sh or Windows: .\scripts\build_win.ps1
   3. Linux/macOS: ./scripts/package.sh or Windows: .\scripts\package_win.ps1

As a note, the package script will download the warp packer to generate a single binary with the CyLR resources and full CLR runtime for portability. This means that the binary will unpack in a temporary location for execution. According to the warp documentation, these locations are:

Packages cache location:

• Linux: $HOME/.local/share/warp/packages
• macOS: $HOME/Library/Application Support/warp/packages
• Windows: %LOCALAPPDATA%\warp\packages

Runners cache location:

• Linux: $HOME/.local/share/warp/runners
• macOS: $HOME/Library/Application Support/warp/runners
• Windows: %LOCALAPPDATA%\warp\runners

These caches are only created on first execution or when the packed binary is updated.

• Jason Yegge
• Alan Orlikoski