Full Report
Threat hunters have shed light on a "sophisticated and evolving malware toolkit" called Ragnar Loader that's used by various cybercrime and ransomware groups like Ragnar Locker (aka Monstrous Mantis), FIN7, FIN8, and Ruthless Mantis (ex-REvil). "Ragnar Loader plays a key role in keeping access to compromised systems, helping attackers stay in networks for long-term operations," Swiss
Analysis Summary
# Tool/Technique: Ragnar Loader (also known as Sardonic)
## Overview
Ragnar Loader is a sophisticated and evolving malware toolkit primarily used by various cybercrime and ransomware groups to establish persistent access within compromised networks for long-term operations. It functions as a complex backdoor capable of evading detection and supporting post-exploitation activities, including the delivery of ransomware payloads.
## Technical Details
- Type: Malware family (Loader/Backdoor)
- Platform: Windows (utilizes PowerShell, also has a Linux ELF component)
- Capabilities: Establishing persistent footholds, sophisticated process injection, strong encryption/encoding, lateral movement, remote command execution, file exfiltration, and running DLL plugins/shellcode.
- First Seen: Documented by Bitdefender in August 2021; believed to be in use since 2020.
## MITRE ATT&CK Mapping
This summary maps observed behaviors to potential ATT&CK T/S/Techniques based on the described capabilities:
- **TA0003 - Persistence**
- T1547 - Boot or Logon Autostart Execution: Implied by need for long-term access.
- T1053.005 - Scheduled Task/Job
- **TA0005 - Defense Evasion**
- T1027 - Obfuscated Files or Information (Use of RC4, Base64, obfuscation)
- T1055 - Process Injection (Specifically mentioned as dynamic process injection)
- T1071.001 - Application Layer Protocol: Web Protocols (Implied C2 communication)
- **TA0011 - Command and Control**
- T1071 - Application Layer Protocol (C2 panel communication)
- **TA0008 - Lateral Movement**
- T1550.002 - Use Alternate Authentication Material: Implied by token manipulation and lateral movement file.
## Functionality
### Core Capabilities
- **Initialization & Execution:** Delivered as an archive package containing multiple components, often executed using PowerShell.
- **Stealth & Evasion:** Employs strong encryption (RC4) and encoding (Base64) to conceal operations. Integrates anti-analysis techniques to resist detection.
- **Persistence:** Designed to establish long-term footholds within targeted environments.
- **Command Execution:** Allows remote actors to control the infected system via a Command-and-Control (C2) panel.
### Advanced Features
- **Process Manipulation:** Utilizes sophisticated and dynamic process injection strategies, including token manipulation.
- **Modular Operation:** Capable of running DLL plugins and shellcode for various backdoor operations.
- **Data Access:** Ability to read and exfiltrate the contents of arbitrary files.
- **Lateral Movement:** Uses a separate PowerShell-based pivoting file to move within the network.
- **Linux Component:** Includes a Linux executable ELF file named `bc` to facilitate remote connections and direct command-line execution on Linux systems.
## Indicators of Compromise
*Note: Specific, current IOCs were not listed in the provided text excerpt, thus this section is populated with expected placeholder or general types based on the description.*
- File Hashes: [Not Specified in text]
- File Names: `bc` (Linux ELF component), Archive package components.
- Registry Keys: [Not Specified in text]
- Network Indicators: C2 communications controlled via a C2 panel (defanged format: `hxxp://c2server[.]example`).
- Behavioral Indicators: Execution initiated via PowerShell, dynamic process injection, unusual token manipulation activity.
## Associated Threat Actors
- FIN7
- FIN8 (known to use modified versions, sometimes linking to Sardonic)
- Ragnar Locker (also known as Monstrous Mantis)
- Ruthless Mantis (ex-REvil)
## Detection Methods
- Signature-based detection: Signatures targeting known file hashes or strings related to RC4/Base64 decryption routines.
- Behavioral detection: Monitoring for dynamic process injection, unexpected use of PowerShell for execution/pivoting, and unusual token manipulation.
- YARA rules: Rules targeting the unique obfuscated logic or the `bc` ELF component.
## Mitigation Strategies
- Prevention measures: Strict application control policies; limiting PowerShell execution via AppLocker or similar controls.
- Hardening recommendations: Implementing network segmentation to contain lateral movement; regular auditing of scheduled tasks and persistent mechanisms.
## Related Tools/Techniques
- Ragnar Locker (Ransomware frequently deployed after initial compromise)
- Sardonic (Alias for Ragnar Loader)
- BlackCat (Ransomware previously deployed by FIN8 using this loader)