6. Scan Modes

You can select between 6 different scan modes in THOR:

  • Default
    We recommend using the default scan mode for all sweeping activity. Scans take from 1 to 6 hours depending on the partition size and number of interesting files.
    In default mode, THOR automatically choses "Soft" mode if the system has only limited CPU and RAM resources.
    There's a special "Lab Scanning" (--lab) method described in section 9.1 that disables many limitations and allows to scan mounted images in a Lab scenario, even with multiple THOR instances on a single Workstation.
  • Quick (--quick)
    This mode is the fastest one and oriented on the "Pareto Principe", covering 80% of the modules and check in 20% of the normal scan time. In "quick" mode, THOR skips elements that have not been created or modified within the last 2 days in the "Eventlog", “Registry” and "Filescan" modules. A set of 40+ directories will still be checked completely (e.g. AppData, Recycler, System32). "Quick" mode is known to be the "preventive" scan mode – less intense and very fast.

Themed scan modes:

  • Soft (--soft / force disable with --nosoft)
    This mode disables all modules and checks that could be risky for system stability.
    It is automatically activated on (more details in chapter Automatic Soft Mode):
    - Systems with only a single CPU core
    - Systems with less than 1024 MB of RAM
  • Lab Scan (--lab)
    This mode scan only the filesystem and disable all other modules. (see chapter Special Scan Modes for more details and flags used in this scan mode)
    Example: ./thor64 --lab -p /mnt/image_c/
  • Intense (--intense)
    This mode is meant for system scanning in a non-productive or lab environment. It disables several speed optimizations and enables time-consuming extra checks for best detection results.
  • Difference (--diff)
    The Diff Mode looks for a last scan and last finished modules in the local THOR DB and scans only elements on disk that have been changed or created since the last scan start. This mode applies short-cuts to the “Filesystem”, “Eventlog” and “Registry” modules. Diff scans are typically the shortest scans but require a completed previous scan. This scan mode is also susceptible to the so-called “Timestomping”.

The following tables give an overview on the active modules and features in the different scan modes. The ‘modules’ section lists all available modules, whereas the ‘features’ section lists only features that are handled differently in the different scan modes.

6.1. Modules

6.1.1. OS Module Overview

Module

Windows

Linux

MacOS

File System Scan

Supported

Supported

Supported

Registry Scan

Supported

Not Supported

Not Supported

SHIM Cache Scan

Supported

Not Supported

Not Supported

Mutex Check

Supported

Not Supported

Not Supported

Named Pipes Check

Supported

Not Supported

Not Supported

DNS Cache Check

Supported

Supported

Supported

Hotfix Check

Supported

Not Supported

Not Supported

Hosts File Check

Supported

Supported

Supported

Firewall Config Check

Supported

Supported

Not Supported

Network Share Check

Supported

Not Supported

Not Supported

Logged In Check

Supported

Supported

Supported

Process Check

Supported

Supported*

Supported*

Service Check

Supported

Supported

Not Supported

Autoruns Check

Supported

Supported

Supported

Rootkit Check

Supported

Supported

Not Supported

LSA Sessions Analysis

Supported

Not Supported

Not Supported

User Account Check

Supported

Supported

Supported

User Profile Check

Supported

Supported

Supported

Network Sessions Check

Supported

Not Supported

Not Supported

Scheduled Tasks Analysis

Supported

Not Supported

Not Supported

WMI Startup Check

Supported

Not Supported

Not Supported

At Entries Check

Supported

Not Supported

Not Supported

MFT Analysis

Supported

Not Supported

Not Supported

Eventlog Analysis

Supported

Not Supported

Not Supported

KnowledgeDB Check

Not Supported

Not Supported

Supported

Environment Variables Check

Supported

Supported

Supported

Crontab Check

Not Supported

Supported

Not Supported

Integrity Check

Not Supported

Supported

Not Supported

Event Check

Supported

Not Supported

Not Supported

* = No process memory scan with YARA rules

6.1.2. Scan Mode Overview

Module

Normal

Quick

Soft

Intense

File System Scan

Reduced

Registry Scan

SHIM Cache Scan

Mutex Check

Disabled

Named Pipes Check

DNS Cache Check

Hotfix Check

Disabled

Hosts File Check

Disabled

Firewall Config Check

Disabled

Disabled

Network Share Check

Disabled

Logged In Check

Enabled*

Disabled

Process Check

Reduced**

Service Check

Autoruns Check

Rootkit Check

LSA Sessions Analysis

Disabled

User Account Check

Enabled*

User Profile Check

Enabled*

Disabled

Network Sessions Check

Enabled*

Disabled

Scheduled Tasks Analysis

WMI Startup Check

At Entries Check

MFT Analysis

Disabled

Disabled

Disabled

Enabled

Eventlog Analysis

Disabled

KnowledgeDB Check

Environment Variables Check

Crontab Check

Integrity Check

Event Check

* = Disabled on Domain Controllers
** = No process memory scan with YARA rules

6.2. Features

6.2.1. Feature Scan Mode Overview

Feature

Normal

Quick

Soft

Intense

Sigma Scan

Disabled

Disabled

Disabled

Enabled

EXE Decompression

Enabled**

Enabled

Disabled

Enabled

Archive Scan

Enabled

Enabled

Enabled

Enabled

Double Pulsar Check

Enabled**

Enabled

Disabled

Enabled

Groups XML Analysis

Enabled

Enabled

Enabled

Enabled

Vulnerability Check

Enabled

Enabled

Enabled

Enabled

Web Server Dir Scan

Enabled

Disabled

Enabled

Enabled

WMI Persistence

Enabled

Enabled

Enabled

Enabled

Registry Hive Scan

Enabled*

Enabled

Enabled

Enabled

AmCache Analysis

Enabled

Enabled

Enabled

Enabled

Process Handle Check

Enabled

Enabled

Enabled

Enabled

Process Connections Check

Enabled

Enabled

Enabled

Enabled

Windows Error Report (WER)

Enabled

Enabled

Enabled

Enabled

Windows At Job File Analysis

Enabled

Enabled

Enabled

Enabled

EVTX File Scanning

Enabled

Disabled

Enabled

Enabled

Prefetch Library Scanning

Enabled

Enabled

Enabled

Enabled

Memory Dump DeepDive

Disabled

Disabled

Disabled

Enabled

Text Log File Scanning

Enabled

Disabled

Enabled

Enabled

Shellbag Entry Analysis

Enabled

Enabled

Enabled

Enabled

Authorized Key File Analysis

Enabled

Enabled

Enabled

Enabled

Bifrost File Upload

Enabled

Enabled

Enabled

Enabled

Malicious Domain Check

Enabled

Enabled

Enabled

Enabled

File Scan

Enabled

Enabled

Enabled

Enabled

Cobalt Strike Beacon Parsing

Enabled

Enabled

Enabled

Enabled

Process Integrity Check

Disabled

Disabled

Disabled

Enabled**

SHIM Cache Analysis

Enabled

Enabled

Enabled

Enabled

* = Disabled on Domain Controllers
** = Only supported on Windows

6.2.2. Feature caller list

The following table gives an overview of THORs features and how they are called by the different modules and other features.

Feature

Callers

Sigma Scan

Eventlog, Log file scanning

EXE Decompression

File Scan

Archive Scan

File Scan

Double Pulsar Check

Rootkit Check

Groups XML Analysis

File Scan

Vulnerability Check

File Scan

Web Server Dir Scan

Process Check

WMI Persistence

File Scan

Registry Hive Scan

File Scan

AmCache Analysis

File Scan

Process Handle Check

Process Check

Process Memory Check

Process Check

Process Connections Check

Process Check

Windows Error Report (WER)

File Scan

Windows At Job File Analysis

File Scan

EVTX File Scanning

File Scan

Prefetch Library Scanning

File Scan

Memory Dump DeepDive

File Scan

Text Log File Scanning

File Scan

Shellbag Entry Analysis

Registry Hive Scan

Authorized Key File Analysis

File Scan

Bifrost File Upload

File Scan

Malicious Domain Check

File Scan

File Scan

Most modules and features

Cobalt Strike Beacon Parsing

File Scan, Process Check

Process Integrity Check

Process Check

SHIM Cache Analysis

SHIM Cache Scan, Registry Hive