Trigona Ransomware: Custom CLI Data Exfiltration Tool — Detection and Mitigation | Security Arsenal

The Trigona ransomware operation has evolved its tactics to bypass traditional signature-based defenses. According to intelligence from March 2026, threat actors have replaced off-the-shelf utilities like Rclone and MegaSync with a custom-built command-line tool for data exfiltration. This shift allows attackers to steal data faster and evade detection mechanisms calibrated to flag standard file-sync binaries. For defenders, this means relying solely on static indicators for known utilities is no longer sufficient. We must pivot to behavioral analysis to identify the execution of unsigned, custom tools masquerading as legitimate system processes within user directories.

Technical Analysis

Affected Products/Platforms: Primarily Windows-based environments where Trigona gains initial access (often via exposed RDP or valid credentials).
CVE Identifiers: N/A (This is a TTP shift, not a vulnerability exploitation).
Attack Mechanism: The attack chain typically follows a pattern of initial access -> privilege escalation -> discovery. In this new iteration, instead of deploying a signed utility like rclone.exe to move data to cloud storage, the actors execute a custom, unsigned command-line interface (CLI) tool. This tool is likely dropped in a user-writable directory (e.g., AppData or Temp) and executed directly. It establishes outbound connections to attacker-controlled infrastructure, exfiltrating large volumes of data without triggering signatures associated with legitimate sync software.
Exploitation Status: Confirmed active exploitation. Symantec researchers have observed this tool in-the-wild during recent Trigona incidents.

Detection & Response

Detecting custom tooling requires identifying anomalies in process lineage and code signing. Since the binary is custom, it will likely lack a valid digital signature and originate from suspicious paths.

SIGMA Rules

YAML

---
title: Trigona Custom Tool - Unsigned Process Network Connection
id: a1b2c3d4-5678-90ab-cdef-1234567890ab
status: experimental
description: Detects unsigned processes originating from user directories initiating network connections, indicative of custom exfiltration tools like Trigona's new utility.
references:
 - https://securityaffairs.com/191294/cyber-crime/trigona-ransomware-adopts-custom-tool-to-steal-data-and-evade-detection.html
author: Security Arsenal
date: 2026/03/17
tags:
 - attack.exfiltration
 - attack.t1041
logsource:
 category: network_connection
 product: windows
detection:
 selection:
   Initiated: 'true'
   Image|contains:
     - '\AppData\'
     - '\Temp\'
   SignatureStatus:
     - 'Untrusted'
     - 'Unsigned'
     - 'Unknown'
 filter:
   Image|contains:
     - '\Program Files\'
     - '\Program Files (x86)\'
     - '\Windows\System32\'
     - '\Windows\SysWOW64\'
falsepositives:
  - Legitimate unsigned internal tools (rare)
level: high
---
title: Suspicious CLI Parameters with Network Destination
id: b2c3d4e5-6789-01ab-cdef-234567890bcd
status: experimental
description: Detects processes using command-line arguments typical of data exfiltration (upload, send, host) combined with an IP address or domain, targeting behavior of custom tools.
references:
 - https://attack.mitre.org/techniques/T1059/
author: Security Arsenal
date: 2026/03/17
tags:
  - attack.execution
  - attack.t1059.003
logsource:
  category: process_creation
  product: windows
detection:
  selection_cli:
    CommandLine|contains:
      - '-upload'
      - '--put'
      - '--send'
      - '--host'
      - '--server'
  selection_network:
    CommandLine|contains:
      - 'http://'
      - 'https://'
      - 'ftp://'
      - '192.168.'
      - '10.'
  filter_legit:
    Image|contains:
      - '\Program Files\'
      - '\Program Files (x86)\'
falsepositives:
  - Administrators using specific CLI tools for backups
level: medium

KQL (Microsoft Sentinel / Defender)

KQL — Microsoft Sentinel / Defender

// Hunt for unsigned processes establishing network connections from user directories
DeviceNetworkEvents
| where InitiatingProcessFolderPath contains "AppData" or InitiatingProcessFolderPath contains "Temp"
| where InitiatingProcessVersionInfo is not null
| extend IsSigned = InitiatingProcessVersionInfo.CompanyName != ""
| where isempty(InitiatingProcessVersionInfo.CompanyName) or InitiatingProcessVersionInfo.FileVersion == "Unknown"
| project Timestamp, DeviceName, InitiatingProcessFileName, InitiatingProcessFolderPath, RemoteUrl, RemoteIP, RemotePort
| order by Timestamp desc

Velociraptor VQL

VQL — Velociraptor

-- Hunt for unsigned executables in user directories that have active network connections
SELECT Pid, Name, Exe, CommandLine, Username,
       Sig.Signer, Sig.Status
FROM pslist()
WHERE Exe =~ 'C:\\Users\\.*\\AppData\\.*\\.exe'
  AND (Sig.Status != "VALID" OR Sig.Status IS NULL)

Remediation Script (PowerShell)

PowerShell

<#
.SYNOPSIS
    Detects and isolates potential custom exfiltration tools.
.DESCRIPTION
    Scans user profiles for unsigned executables modified in the last 7 days 
    originating from AppData or Temp directories.
#>

$DateThreshold = (Get-Date).AddDays(-7)
$UserProfiles = Get-ChildItem "C:\Users\" -Directory

Foreach ($Profile in $UserProfiles) {
    $Paths = @(
        "$($Profile.FullName)\AppData\Local\Temp\",
        "$($Profile.FullName)\AppData\Roaming\",
        "$($Profile.FullName)\AppData\Local\"
    )
    
    Foreach ($Path in $Paths) {
        if (Test-Path $Path) {
            Get-ChildItem -Path $Path -Filter *.exe -Recurse -ErrorAction SilentlyContinue | 
            Where-Object { $_.LastWriteTime -gt $DateThreshold } | 
            ForEach-Object {
                $Signature = Get-AuthenticodeSignature $_.FullName
                if ($Signature.Status -ne "Valid") {
                    Write-Host "WARNING: Unsigned executable found: $($_.FullName)" -ForegroundColor Red
                    # Optional: Quarantine logic here
                }
            }
        }
    }
}

Remediation

Immediate containment is critical upon detection of Trigona activity:

Isolate Hosts: Immediately disconnect infected endpoints from the network to prevent further data exfiltration via the custom tool.
Block Artifacts: If the custom tool's hash (SHA256) or IP addresses/C2 domains are identified during the investigation, block them at the perimeter and on endpoints.
Credential Reset: Assume the attacker has credentials. Force a password reset for all accounts, specifically focusing on domain and local administrator accounts used on the affected machines.
Policy Enforcement: Implement Application Control (AppLocker or Windows Defender Application Control) to block the execution of binaries from user-writable directories (%AppData%, %Temp%, %LocalAppData%). n5. Review RDP Access: Trigona frequently enters via RDP. Ensure RDP is disabled or restricted, and MFA is enforced for all remote access.

Related Resources

Security Arsenal Incident Response Services AlertMonitor Platform Book a SOC Assessment incident-response Intel Hub

Trigona Ransomware: Custom CLI Data Exfiltration Tool — Detection and Mitigation