T1486

Data Encrypted for Impact

Impact Last updated:

Adversaries may encrypt data on target systems or on large numbers of systems in a network to interrupt availability to system and network resources. They can attempt to render stored data inaccessible by encrypting files or data on local and remote drives and withholding access to a decryption key. This may be done in order to extract monetary compensation from a victim in exchange for decryption or a decryption key (ransomware) or to render data permanently inaccessible in cases where the key is not saved or transmitted. In the case of ransomware, it is typical that common user files like Office documents, PDFs, images, videos, audio, text, and source code files will be encrypted and often renamed or tagged with specific file markers. Adversaries may also encrypt critical system files, disk partitions, MBR, virtual machines hosted on ESXi, or cloud storage objects.

What is T1486 Data Encrypted for Impact?

Data Encrypted for Impact (T1486) maps to the Impact tactic — the adversary is trying to manipulate, interrupt, or destroy your systems and data in MITRE ATT&CK.

This page provides production-ready detection logic for Data Encrypted for Impact, covering the data sources and telemetry it touches: File: File Modification, File: File Creation, Command: Command Execution, Process: Process Creation, Microsoft Defender for Endpoint. The queries below are rated critical severity at high confidence, and ship for 7 SIEM platforms — KQL, SPL, Elastic, QRadar, Sumo, YARA-L, LogScale.

MITRE ATT&CK

Tactic
Impact
Technique
T1486 Data Encrypted for Impact
Canonical reference
https://attack.mitre.org/techniques/T1486/
Microsoft Sentinel / Defender
kusto
let TimeWindow = 1h;
let RenameThreshold = 50;
let ShadowDeleteCommands = dynamic(["vssadmin delete shadows", "vssadmin.exe delete shadows", "wmic shadowcopy delete", "bcdedit /set {default} recoveryenabled no", "bcdedit /set {default} bootstatuspolicy ignoreallfailures", "wbadmin delete catalog", "wbadmin delete systemstatebackup"]);
// Detection 1: Mass file rename/encryption activity
let MassRename = DeviceFileEvents
| where Timestamp > ago(TimeWindow)
| where ActionType in ("FileRenamed", "FileModified", "FileCreated")
| where FileName endswith_any (".encrypted", ".locked", ".crypt", ".enc", ".ransom", ".cry", ".lock64", ".cuba", ".avos", ".avos2", ".play", ".blackbyte")
| summarize
    RenamedFiles = count(),
    UniqueExtensions = dcount(FileName),
    FileTypes = make_set(tostring(split(FileName, ".")[-1]), 10),
    FirstSeen = min(Timestamp),
    LastSeen = max(Timestamp)
    by DeviceName, InitiatingProcessFileName, InitiatingProcessId, InitiatingProcessCommandLine
| where RenamedFiles > RenameThreshold;
// Detection 2: Shadow copy deletion and recovery sabotage
let ShadowDelete = DeviceProcessEvents
| where Timestamp > ago(TimeWindow)
| where ProcessCommandLine has_any (ShadowDeleteCommands)
| project Timestamp, DeviceName, AccountName, FileName, ProcessCommandLine, InitiatingProcessFileName;
// Combine both signals
MassRename
| join kind=leftouter (ShadowDelete) on DeviceName
| extend ShadowsDeleted = isnotempty(ProcessCommandLine)
| extend RansomwareConfidence = case(
    RenamedFiles > 500 and ShadowsDeleted, "critical",
    RenamedFiles > 200 or ShadowsDeleted, "high",
    RenamedFiles > RenameThreshold, "medium",
    "low")
| project FirstSeen, LastSeen, DeviceName, InitiatingProcessFileName, InitiatingProcessCommandLine, RenamedFiles, UniqueExtensions, FileTypes, ShadowsDeleted, RansomwareConfidence
| sort by RenamedFiles desc

Detects ransomware activity through two correlated signals: (1) mass file encryption indicated by high volumes of file renames to known ransomware extensions (.encrypted, .locked, .crypt, .lock64, .cuba, .avos, .play, .blackbyte), and (2) volume shadow copy deletion and recovery sabotage via vssadmin, wmic, bcdedit, and wbadmin. Correlates both signals on the same device for high-confidence ransomware detection. A combined signal (mass rename + shadow delete) is rated critical.

critical severity high confidence

Data Sources

File: File Modification File: File Creation Command: Command Execution Process: Process Creation Microsoft Defender for Endpoint

Required Tables

DeviceFileEvents DeviceProcessEvents

False Positives

  • Legitimate encryption tools (BitLocker, VeraCrypt, 7-Zip) encrypting large numbers of files during backup operations
  • File migration or archival tools that rename files with new extensions during processing
  • Anti-ransomware tools that create decoy/canary files with ransomware-like extensions for honeypot detection
  • Disaster recovery testing that involves intentional shadow copy deletion as part of DR exercises

Sigma rule & cross-platform mapping

The detection logic for Data Encrypted for Impact (T1486) above is provided in a vendor-neutral form so you can deploy it on any SIEM. The same logic is shipped here as native KQL (Microsoft Sentinel / Defender), SPL (Splunk), Elastic (Elastic Security (EQL)), QRadar (IBM QRadar (AQL)), Sumo (Sumo Logic CSE), YARA-L (Google Chronicle / SecOps), LogScale (CrowdStrike LogScale (CQL)) queries. In Sigma terms, this detection targets the following logsource:

logsource:
  category: process_creation
  product: windows

Browse the community-maintained Sigma rules for this technique:


Testing Methodology

Validate this detection against 4 adversary techniques from Atomic Red Team. Each test below lists the behaviour to exercise and the telemetry you should expect to see. Executable commands and cleanup steps are available with Pro.

  1. Test 1Volume Shadow Copy Deletion via vssadmin

    Expected signal: Sysmon Event ID 1: Process creation for vssadmin.exe with 'delete shadows /all /quiet' command line. Windows Security Event ID 4688 with same details. VSS Event ID 8224 in System log confirming shadow deletion.

  2. Test 2Recovery Sabotage via bcdedit

    Expected signal: Sysmon Event ID 1: Two process creation events for bcdedit.exe with /set commands. Windows Security Event ID 4688 with command line auditing. Registry modification events for BCD store changes.

  3. Test 3Mass File Encryption Simulation

    Expected signal: Sysmon Event ID 11: 100 file creation events for .docx files, followed by 100 file rename events to .docx.encrypted. The burst of file operations in a short time window from a single process is the key telemetry pattern.

  4. Test 4Ransom Note Drop Simulation

    Expected signal: Sysmon Event ID 11: 10 file creation events for README_DECRYPT.txt in different directories. The identical filename across multiple directories is the key pattern.

Unlock Pro Content

Get the full detection package for T1486 including response playbook, investigation guide, and atomic red team tests.

Response PlaybookInvestigation GuideHunting QueriesAtomic Red Team TestsTuning Guidance

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