Scanner for Simple Indicators of Compromise

Detection is based on four detection methods:

1. File Name IOC
   Regex match on full file path/name

2. Yara Rule Check
   Yara signature match on file data and process memory

3. Hash Check
   Compares known malicious hashes (MD5, SHA1, SHA256) with scanned files
   
4. C2 Back Connect Check
   Compares process connection endpoints with C2 IOCs (new since version v.10)

Additional Checks:

1. Regin filesystem check (via --reginfs)
2. Process anomaly check (based on [Sysforensics](http://goo.gl/P99QZQ)
3. SWF decompressed scan (new since version v0.8)
4. SAM dump check

The Windows binary is compiled with PyInstaller and should run as x86 application on both x86 and x64 based systems.

• Download the newest version of LOKI from the releases section
• Extract the program package
• Run loki-upgrader.exe on system with Internet access to retrieve the newest signatures
• Bring the program folder to a target system that should be scanned: removable media, network share, folder on target system
• Open a command line "cmd.exe" as Administrator and run it from there (you can also run LOKI without administrative privileges but some checks will be disabled and relevant objects on disk will not be accessible)

• The resulting report will show a GREEN, YELLOW or RED result line.
• Please analyse the findings yourself by:
  1. uploading non-confidential samples to Virustotal.com
  2. Search the web for the filename
  3. Search the web for keywords from the rule name (e.g. EQUATIONGroupMalware_1 > search for "Equation Group")
  4. Search the web for the MD5 hash of the sample
• Please report back false positives via the "Issues" section, which is accessible via the right sidebar (mention the false positive indicator like a hash and/or filename and the rule name that triggered)

No requirements if you use the compiled EXE.

If you want to build it yourself:

• yara : It's recommended to use the most recent version of the compiled packages for Windows (x86) - Download it from here: https://github.com/VirusTotal/yara-python/releases
• colorama : to color it up
• psutil : process checks
• pywin32 : path conversions (PyInstaller issue; Windows only)

usage: loki.exe [-h] [-p path] [-s kilobyte] [-l log-file] [--printAll]
                [--noprocscan] [--nofilescan] [--noindicator] [--reginfs]
                [--dontwait] [--intense] [--csv] [--onlyrelevant] [--nolog]
                [--update] [--debug]

Loki - Simple IOC Scanner

optional arguments:
  -h, --help      show this help message and exit
  -p path         Path to scan
  -s kilobyte     Maximum file size to check in KB (default 2048 KB)
  -l log-file     Log file
  --printAll      Print all files that are scanned
  --noprocscan    Skip the process scan
  --nofilescan    Skip the file scan
  --noindicator   Do not show a progress indicator
  --reginfs       Do check for Regin virtual file system
  --dontwait      Do not wait on exit
  --intense       Intense scan mode (also scan unknown file types and all
                  extensions)
  --csv           Write CSV log format to STDOUT (machine processing)
  --onlyrelevant  Only print warnings or alerts
  --nolog         Don't write a local log file
  --update        Update the signatures from the "signature-base" sub
                  repository
  --debug         Debug output

Since version 0.15 the Yara signatures reside in the sub-repository signature-base. You will not get the sub-repository by downloading the LOKI as ZIP file. It will be included when you clone the repository.

The IOC files for hashes and filenames are stored in the './signature-base/iocs' folder. All '.yar' files placed in the './signature-base/yara' folder will be initialized together with the rule set that is already included. Use the 'score' value to define the level of the message upon a signature match.

You can add hash, c2 and filename IOCs by adding files to the './signature-base/iocs' subfolder. All hash IOCs and filename IOC files must be in the format used by LOKI (see the default files). The files must have the strings "hash", "filename" or "c2" in their name to get pulled during initialization.

For Hash IOCs (divided by newline; hash type is detected automatically)

Hash;Description [Reference]

For Filename IOCs (divided by newline)

Filename as Regex;Description [Reference]

Since version v0.16.2 LOKI supports the definition of user-defined excludes via "excludes.cfg" in the new "./config" folder. Each line represents a regular expression that gets applied to the full file path during the directory walk. This way you can exclude certain directories regardless of their drive name, file extensions in certain folders and all files and directories that belong to a product that is sensitive to antivirus scanning.

The '''exclude.cfg''' looks like this:

# Excluded directories
#
# - add directories you want to exclude from the scan
# - double escape back slashes
# - values are case-insensitive
# - remember to use back slashes on Windows and slashes on Linux / Unix / OSX
# - each line contains a regex that matches somewhere in the full path (case insensitive)
#   e.g.:
#   Regex: \\System32\\
#   Matches C:\Windows\System32\cmd.exe
#
#   Regex: /var/log/[^/]+\.log
#   Matches: /var/log/test.log
#   Not Matches: /var/log/test.gz
#

# Useful examples
\\Ntfrs\\
\\Ntds\\
\\EDB[^\.]+\.log
Sysvol\\Staging\\Nntfrs_cmp
\\System Volume Information\\DFSR

Since version v0.10 LOKI includes various threat intel receivers using the public APIs of these services to retrieve and store the IOCs in a format that LOKI understands. It is no problem if these indicators overlap with the ones already included. Loki uses a filename regex or hash only once. (no performance impact)

The threat intel receivers have also been moved to the signature-base sub repository with version 0.15 and can be found in "./signature-base/threatintel".

Provide your API key via -k APIKEY or set it in the script header.

It's a simple script that downloads your subscribed events/iocs from Alienvault OTX and stores them in the correct format in the './iocs' subfolder. The script is located in the "./threatintel" folder and is named "get-otx-iocs.py". (see requirements above)

usage: get-otx-iocs.py [-h] [-k APIKEY] [-o dir] [--verifycert] [--debug]

OTX IOC Receiver

optional arguments:
  -h, --help    show this help message and exit
  -k APIKEY     OTX API key
  -o dir        Output directory
  --verifycert  Verify the server certificate
  --debug       Debug output

A simple script that downloads your subscribed events/iocs from a custom MISP instance and stores them in the correct format in the './iocs' subfolder. YARA rules stored in MISP will be written to the './iocs/yara' subfolder and automatically initialized during startup. The script is located in the "./threatintel" folder and is named "get-misp-iocs.py". (see requirements above)

usage: get-misp-iocs.py [-h] [-u URL] [-k APIKEY] [-l tframe] [-o dir]
                        [-y yara-dir] [--verifycert] [--debug]

MISP IOC Receiver

optional arguments:
  -h, --help    show this help message and exit
  -u URL        MISP URL
  -k APIKEY     MISP API key
  -l tframe     Time frame (e.g. 2d, 12h - default=30d)
  -o dir        Output directory
  -y yara-dir   YARA rule output directory
  --verifycert  Verify the server certificate
  --debug       Debug output

Loki Scan

Regin Matches

Regin False Positives

Hash based IOCs

File Name based IOCs

Generated log file

LOKI scanner on our company homepage https://www.nextron-systems.com/loki/

Twitter @cyb3rOps @thor_scanner

If you are interested in a corporate solution for APT scanning, check out Loki's big brother THOR.

Download PyInstaller, switch to the pyinstaller program directory and execute:

python ./pyinstaller.py -F C:\path\to\loki.py

This will create a loki.exe in the subfolder ./loki/dist.

To include the msvcr100.dll to improve the target os compatibility change the line in the file ./loki/loki.spec that contains a.binaries, to the following:

a.binaries + [('msvcr100.dll', 'C:\Windows\System32\msvcr100.dll', 'BINARY')],

• Download Yara sources from here
• Change to folder yara-python
• Run python setup.py install
• Also install the requirement mentioned above by sudo pip install colorama

The compiled scanner may be detected by antivirus engines. This is caused by the fact that the scanner is a compiled python script that implement some file system and process scanning features that are also used in compiled malware code.

If you don't trust the compiled executable, please compile it yourself.

Loki - Simple IOC Scanner Copyright (c) 2015 Florian Roth

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/