UNC6692 'Snow' Malware Campaign: Defending Against Email Bombing and Social Engineering

---
title: Potential Email Bombing Activity - High Volume Recipient
id: 9e8f7a6b-5c4d-3e2f-1a0b-9c8d7e6f5a4b
status: experimental
description: Detects a high volume of emails received by a single recipient within a short timeframe, indicative of an email bombing attack used to bury security alerts.
references:
  - https://attack.mitre.org/techniques/T1566/
author: Security Arsenal
date: 2024/05/23
tags:
  - attack.initial_access
  - attack.t1566
logsource:
  product: exchange
  service: mail_transport
detection:
  condition: selection
  selection:
    RecipientAddress|contains: '@'
    TotalRecipients: 1
  timeframe: 5m
  count:
    RecipientAddress|count: 50
falsepositives:
  - Legitimate mass mailing
level: medium
---
title: Suspicious Child Process of Email Client
id: 1b2c3d4e-5f6a-7b8c-9d0e-1f2a3b4c5d6e
status: experimental
description: Detects execution of scripting binaries or shells spawned directly from an email client process, common in social engineering attacks following credential theft.
references:
  - https://attack.mitre.org/techniques/T1204/
author: Security Arsenal
date: 2024/05/23
tags:
  - attack.execution
  - attack.t1204.002
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    ParentImage|endswith:
      - '\OUTLOOK.EXE'
      - '\thunderbird.exe'
    Image|endswith:
      - '\powershell.exe'
      - '\cmd.exe'
      - '\wscript.exe'
      - '\cscript.exe'
  filter:
    CommandLine|contains: 'Office'
falsepositives:
  - Legitimate automation
level: high
---
title: UNC6692 Snow Malware Execution
id: 2c3d4e5f-6a7b-8c9d-0e1f-2a3b4c5d6e7f
status: experimental
description: Detects execution of known Snow malware family binaries (Snowbelt, Snowglaze, Snowbasin) associated with UNC6692.
references:
  - https://www.securityweek.com/unc6692-uses-email-bombing-social-engineering-to-deploy-snow-malware/
author: Security Arsenal
date: 2024/05/23
tags:
  - attack.persistence
  - attack.s0127
logsource:
  category: process_creation
  product: windows
detection:
  selection:
    Image|contains:
      - 'Snowbelt'
      - 'Snowglaze'
      - 'Snowbasin'
  condition: selection
falsepositives:
  - None expected
level: critical

// Hunt for high volume of incoming emails to specific users (Email Bombing)
// Note: Adjust table name based on specific log source (ExchangeOnline, OfficeActivity)
ExchangeOnline
| where TimeGenerated > ago(1d)
| where RecipientAddress != ""
| summarize Count = count() by RecipientAddress, bin(TimeGenerated, 5m)
| where Count > 50
| project TimeGenerated, RecipientAddress, Count
| order by Count desc

// Hunt for Snow Malware Processes
DeviceProcessEvents
| where Timestamp > ago(7d)
| where FileName has_any ("Snowbelt", "Snowglaze", "Snowbasin")
| project Timestamp, DeviceName, AccountName, InitiatingProcessFileName, FileName, SHA256

// Hunt for suspicious processes spawned by Outlook (Social Engineering Execution)
DeviceProcessEvents
| where Timestamp > ago(1d)
| where InitiatingProcessFileName in~ ("outlook.exe", "thunderbird.exe")
| where FileName in~ ("powershell.exe", "cmd.exe", "wscript.exe", "cscript.exe", "mshta.exe")
| project Timestamp, DeviceName, AccountName, InitiatingProcessCommandLine, FileName, ProcessCommandLine

-- Hunt for UNC6692 Snow Malware Processes
SELECT Pid, Name, CommandLine, Exe, Username, CreateTime
FROM pslist()
WHERE Name =~ 'Snowbelt'
   OR Name =~ 'Snowglaze'
   OR Name =~ 'Snowbasin'

-- Hunt for suspicious child processes of email clients
SELECT Pid, Name, CommandLine, Exe, Username, ParentPid
FROM pslist()
WHERE Name =~ 'powershell.exe'
   OR Name =~ 'cmd.exe'
   OR Name =~ 'wscript.exe'
   OR Name =~ 'cscript.exe'
JOIN SELECT Pid AS ParentPid, Name AS ParentName
FROM pslist()
WHERE ParentName =~ 'OUTLOOK.EXE'

-- Hunt for persistence mechanisms often used by Snow malware
SELECT Key.Path, Key.LastWriteTime, Key.Data.value
FROM glob(globs='\\Software\\Microsoft\\Windows\\CurrentVersion\\Run\\*')
WHERE Key.Path =~ 'Snow'

# UNC6692 Snow Malware Remediation Check
# Scans for presence of Snowbelt, Snowglaze, and Snowbasin executables

$SnowProcesses = @("Snowbelt", "Snowglaze", "Snowbasin")
$RunningProcesses = Get-Process | Where-Object { $SnowProcesses -contains $_.ProcessName }

if ($RunningProcesses) {
    Write-Host "ALERT: Detected Snow Malware Family Processes:" -ForegroundColor Red
    $RunningProcesses | Format-Table Id, ProcessName, Path -AutoSize
    # Terminate malicious processes
    $RunningProcesses | Stop-Process -Force -ErrorAction SilentlyContinue
    Write-Host "Processes terminated. Isolate host immediately for forensic analysis." -ForegroundColor Yellow
} else {
    Write-Host "No Snow malware processes currently running." -ForegroundColor Green
}

# Scan common startup and temp folders for artifacts
$Paths = @("$env:APPDATA", "$env:TEMP", "$env:USERPROFILE\Downloads", "$env:PROGRAMDATA")
$SnowArtifacts = foreach ($Path in $Paths) {
    if (Test-Path $Path) {
        Get-ChildItem -Path $Path -Recurse -Include "*.exe" -ErrorAction SilentlyContinue | Where-Object { 
            $_.Name -match "Snowbelt|Snowglaze|Snowbasin" 
        }
    }
}

if ($SnowArtifacts) {
    Write-Host "ALERT: Found Snow Malware Artifacts on disk:" -ForegroundColor Red
    $SnowArtifacts | Format-Table FullName, CreationTime, LastWriteTime -AutoSize
    # Note: Do not delete files immediately during IR; preserve for evidence first.
} else {
    Write-Host "No Snow malware artifacts found in standard user directories." -ForegroundColor Green
}