THOR v10.2 Changes

New Module “Events”

This module checks registered Events in the system environment as they are used by advanced malware and rootkits. 

We have checked for malicious Events before, in the Rootkit module, but these checks were hardcoded. We’ve spun out that section and can now provide regular updates in a separate signature file. 

The “Events” module extends our set of rootkit related modules that already include the “Mutex” and “Named Pipe” modules.

THOR DB with Timing Statistics

THOR v10.2 features an unencrypted table in THOR DB that shows timing information for the scanned elements. This could help you identifying elements that lengthen scans significantly and determine a time range in which certain elements have been scanned. 

Reduced Output

A new switch “–reduced” allows to limit events to “Warning” and “Alert” types only. 

Other Changes

  • Upgrade to YARA 3.11
  • Improved module messages (better description)
  • Bugfix: Golden ticket detection module reported far too many Kerberos tickets with too long lifetime, message: “Kerberos ticket with very long life time detected – likely a Golden Ticket”. The issue has been fixed. Please make sure that you haven’t filtered / base-lined that event type. 
  • Added ExecFlag to SHIMCache output
  • Apply YARA rules on WMI Event Filters
  • Passing new external YARA variables ‘timezone’ and ‘language’ to registry rule set
  • More robust custom YARA signature initialisation (syntax check and tests before compilation)

New Feature in THOR v10.1 – Remote Scanning

THOR v10.1 features a mode of operation that is especially helpful in incident response or compromise assessment scenarios – remote scanning. 

Imagine that you’re in a firefighting scenario – a breach has been confirmed and management wants to have quick results on the extent of the compromise. 

The new remote scanning feature called “THOR Remote” allows you to perform triage scans on hundreds of remote systems from a single admin workstation. You can think of it as an integrated PsExec. 

No scripting, no agents, no hustle.  

Benefits

  • No agent
  • No scripting
  • Painless scans of many remote systems

Requirements

  • Available on Windows only
  • Accessible remote ports (135/tcp, 445/tcp)
  • Account with local admin rights

All you need is the new version 10.1 of THOR and a command line of an admin user with the required privileges and open Windows ports (135/tcp, 445/tcp) on the remote systems.

THOR will then switch into a new mode of operation and present a command line interface showing scan information and a scrollable pane for each log file. (see screenshot)

THOR writes the log files to a local folder on the admin workstation or sends them via SYSLOG to your SIEM system.  

You can also define a number of concurrent scans (workers) and delay the scan starts to distribute the load evenly among the target systems. This is beneficial when you scan numerous virtual machines running on a few host systems. 

A complete triage scan of your internal domain can’t be more comfortable. 

THOR 10 Fusion Released

THOR 10 Fusion has arrived. 

It replaces our successful scanners THOR 8 and SPARK and combines the best of both worlds. It is a completely new code base that features all modules of our 4 year old compromise assessment flagship THOR 8 and the speed and extra features of our triage scanner SPARK.

You can find an overview of the major changes in this article.

Download

All customers with an active contract (rental license) and license pack users can download THOR 10 from the “downloads” section in the customer portal.

You can find the new manual as PDF in that section and the ‘./docs’ folder of the downloaded program package. 

 

Updates

Please note that signatures updates will be much more frequent due to the decoupling of program and signature files. Make sure to use thor-util version 1.8 or higher. 

We plan to release new signature packs every 1-3 days and new program binaries about once a month. 

The old scanners will receive updates until mid-2019. However, these updates will be less frequent. 

 

ASGARD

After upgrading to ASGARD version 1.10 you’ll immediately see the new scanner in all menus. 

THOR 10 will be the new default for newly scheduled scan jobs. Old scan jobs will not be touched.

Updates of program binaries and signatures can now be managed separately from the “Updates” section. 

 

Changes to Consider

All the old command line options stayed the same as in THOR 8. However, we’d like to bring some addition features and changes to your attention. 

  • The THOR 10 program package now also contains a 64-bit executable (thor-x64.exe), which should produce much better process memory detection results. (ASGARD automatically selects the right binary)
  • Custom settings are now configured via ./conf/thor.yml and not ./conf/thor.cfg.
  • The active modules per scan mode and the log contents have been reworked. You can’t make a comparison with previous THOR 8 scan data. The log format (default) stayed the same, so that old field extractions should still work. 
  • The log contents are more detailed and more consistent (e.g. timestamp format).
  • THOR has more output options (SYSLOG formats and JSON log file output, see manual).
  • Scan durations will change. The scanner is faster but has more active features like “archive YARA scanning” (better detection for Office document macro droppers).
  • Sigma scanning is available, but has to be activated with “–sigma”. It uses all rules from the public rule repository.

See the already mentioned article for more changes. 

 

Get THOR

Check our license packs for many DFIR and SOC scenarios or request a trial of our new scanner.

Questions

If you have any questions, please contact via the support link in the customer portal. 

THOR 10 Fusion – Major Changes

In anticipation of our new scanner THOR 10 Fusion, we would like to show you some of the exciting new features and upcoming changes. 

Modes and Feature Cleanup

We’ve reviewed and reworked all scan modes in order to clarify the overview of active modules and features for the user. 

In the past, it wasn’t always clear which module and feature has been auto-deactivated and auto-activated during the scan runs. 

We’ve dropped the “–fast” mode, which was rarely used intentionally but auto-activated on Workstations.

Most of the modules have been completely rewritten. 

Due to higher scan speeds we didn’t have to make many compromises. The “default” scan should take roughly as long as with THOR 8 but is much more intensive. 

Modules like the “Rootkit” module have been split up in two different sections, one with important and less dangerous checks and one with less relevant checks that could lead to an Antivirus intervention (e.g. Double Pulsar check).

This refactoring allows us to activate the module in “Soft” scan mode and set e.g. “Double Pulsar” as extra feature for that module, which is activated in “Default”, “Quick” and “Intense” scan mode. 

Separate Program and Signature Updates

Former versions of THOR have been shipped and upgraded as a complete package.

The new thor-util allows you to upgrade program files and signatures separately.

We’ll try to publish new signature packs as fast as new YARA signatures get published in VALHALLA 

Time Stamp Harmonization

The timestamps in all the different modules have been harmonized to ANSIC standard.

This was an important step to allow the creation of meaningful timelines of the discovered events. 

Configuration Files Become Scan Templates

THOR 10 uses so-called scan templates in YAML format, instead of the old config file format.

The parameters in these scan templates reflect 1:1 the command line parameters. With these new scan templates it is easy to define a set of parameters for your scan and ship them as the default scan template. 

You can even mix the configurations from multiple scan templates, e.g. define a default template and separate templates with different syslog targets for each branch office.  

 

JSON and Key/Value Output

You can choose from multiple options to influence the output format of the log files and SYSLOG messages sent to  remote servers. 

We handle log messages internally as objects and can easily render JSON or Key/Value pair outputs. 

This greatly simplifies the SIEM integration of all output streams. 

 

Difference Scan

The difference scan makes use of the THOR DB and checks only elements on disk that have been created or changed since the last scan start.

This is a new ultra fast scan mode, albeit susceptible to timestomping attacks. 

Sigma Scanning

THOR 10 inherits the Sigma scanning feature from SPARK and can now apply Sigma rules to local Eventlog entries (Windows) or log files (Windows, Linux and macOS). 

Find more information on the Sigma scanning feature in this older blog post

 

Better Process Memory Matches

Process memory matches now show the matching strings or code sequences found in the memory of scanned processes. 

Tagged Matches

Since our YARA rules are tagged during the integration into VALHALLA, all of them have tags including the MITRE ATT&CK tags, that help your analysts putting matches into context. 

ASGARD Integration

THOR 10 integrates seamlessly with ASGARD and shows up as third scanner next to THOR 8 and SPARK. 

The “Updates” section will show separate update settings for the scanner’s program components and signatures. 

The ASGARD menu to create new THOR 10 hunts contains all command line options dynamically extracted from the current executable.

This way it adapts to all future features and command line options that will be integrated into THOR 10 over time. 

These are only some of the changes coming with THOR 10 Fusion.

We are in schedule and excited to release it in July.

Upcoming : THOR 10 “Fusion”

We are proud to announce the upcoming release of THOR 10 code named “Fusion”.

It will replace our scanners THOR 8 and SPARK before the end of this year. Both of the current scanners will still receive updates until the end of this year. 

THOR 10 “Fusion” combines the advantages of our current scanners, the intensive analysis capabilities of THOR with the unmatched flexibility and speed of SPARK.

It features all modules of THOR 8, including Registry, SHIM Cache, Eventlog, Mutex, WMI, Service and Autoruns analysis.   

It runs on all major operating systems – Windows, Linux and macOS.

With THOR 10 “Fusion” you will not have to decide between an intense or fast scan anymore. THOR 10 provides the best of both worlds. 

We plan to release THOR 10 in July this year. Follow us on twitter or subscribe to the newsletter for updates.

Customers will get a separate notification with changes and instructions for an upgrade.  

THOR 8.53 Feature: Diff Mode

With the upcoming version 8.53 of THOR, we’re testing a new feature called “Difference” or “Diff” mode (–diff).

The idea behind “Diff” mode is that a scan could be much faster, if it would only consider elements that have been created or changed since the last scan on that system. We can apply this principle to various modules and increase scan speed massively.

Diff mode is currently supported in the long running modules

  • Filesystem – files with MAC timestamps older than the last scan (start) will be skipped
  • Registry – registry keys with last modification dates older than the last scan (start) will be skipped
  • Eventlog – runs until it reaches eventlog entries with timestamps older than the last scan (start)

Diff mode requires the use of THOR DB, which is the default but could have been disabled with “–nothordb”. This is necessary to determine information from the last scan, e.g. “when did it start” but also “which modules were used in the last scan”.

The main advantage is an incredible fast scan. Our tests showed that scans in “Diff” mode complete within 5 and 15 minutes. In “Diff” mode, the longest running module is “ProcessCheck” with run times between 3 and 6 minutes.

The main disadvantage of “Diff” mode is the inability to detect Timestomping attacks, in which attackers or malware changes the timestamps of files and other elements.

Important Update Process Changes

As we have announced in May, the old “thor-upgrade.exe” is already out-of-support and the old update servers accessed by “thor-upgrade.exe” will be decommissioned at the end of October.

The new all-round utility “thor-util.exe” now supports all of the features provided by the old “thor-upgrade.exe” including NTLM Authentication with corporate proxy servers.

You can use “thor-util.exe upgrade –help” to see all options of the “upgrade” feature.

Also note that “thor-util” has an “encrypt” feature that allows you to encrypt custom signature files and the “report” feature that creates HTML reports from plain text log files. 

The only valid update servers that should be accessible to get updates from November onward are:

  • update1.nextron-systems.com
  • update2.nextron-systems.com

The “thor-util” utility is part of the THOR and SPARK packages and can also be downloaded from the Customer Portal in the “Downloads” section.

If you are a customer and don’t have access to the Customer Portal yet, please contact us or the respective partner.

New Feature: THOR-util and SPARK-Core-util Signature Encryption

The new THOR-util version 1.2.4 supports the encryption of your custom signatures so that you can deploy your own IOC files and YARA rules in an encrypted form.

We use a public key in the utilities to encrypt the files for our scanners so that admins, Antivirus engines and attackers won’t be able to read the contents of the files.

 

The feature is also available in SPARK Core, our free scanner.

After encryption, place the encrypted IOC files in the “./custom-signatures” directory and the encrypted YARA rules in the “./custom-signatures/yara” directory.

The use of the function is simple. Just point it to a file, a list of files or use wildcards to select a set of files for encryption. The extension of the output file depends on the extension of the input file.

  • IOC Files: .txt > .dat
  • YARA Rules: .yar > .yas
  • Sigma Rules: .yml > .yms

Examples:

thor-util.exe encrypt case44.yar
thor-util.exe encrypt case44-hashes.txt
thor-util.exe encrypt case44-hashes.txt case44.yar
thor-util.exe encrypt case44.*

You can use the “upgrade” feature in both tools to get the newest version of the utility.

thor-util upgrade

ASGARD IOC Management

The upcoming ASGARD version 1.5 comes with a IOC management section in which you can manage your own set of IOCs in text files, YARA and Sigma rules.

You can then select each of the folders when creating a new scan run with THOR or SPARK. Selecting one of these folders will not include the sub folders.

You can schedule and run scans with different IOC, Sigma and YARA rule sets. You can review the included custom signatures in the scan details. 

The following features are not yet implemented in v1.5 but on the roadmap for ASGARD v1.6:

  • Signature verification
  • Exclude the standard rule set (shipped with THOR and SPARK)