Native Windows utility deletes shadow copies or disables recovery

Siemphony@siemphonylowT1490unverified

AN0933's CommandLinePattern knob names six native utilities together — vssadmin, wbadmin, diskshadow, bcdedit, REAgentC and wmic — and this rule now carries a selector for each of them, including the technique's own textbook example, `vssadmin.exe delete shadows /all /quiet`. The vssadmin, wbadmin, wmic shadowcopy and bcdedit selectors are the same observables the corpus's T1486 rule (data/detections/T1486/rule.yml) matches, because MITRE explains T1490 as augmenting T1485/T1486 rather than standing apart from them — a hit here is deliberately redundant with that rule rather than leaving this technique's own folder blind to its most common real-world execution path. `reagentc /disable` (turns off the Windows Recovery Environment's automatic repair) and `diskshadow.exe` invocation are the two commands unique to this rule; diskshadow's scripted shadow-copy deletion happens inside a script file this process-creation event never shows, so the tool's mere presence on the command line is what this rule can see, not what its script does. Every selection matches on CommandLine alone — the diskshadow leg was moved off Image so the rule stays a single-field OR that all four backends render. Renaming any of these six binaries before invoking it removes the matched substring from CommandLine and evades the corresponding selector entirely, identically to how T1486 is evaded. UNVERIFIED AS AUTHORED — derived from MITRE ATT&CK DET0329, not hand-written and not tested by its author. Any lab result is on this rule's own page.Full description

The 4 SIEM queries below are previews produced by Siemphony’s own translator, not pySigma, and none has been executed against a real backend — review before you deploy.

detection.yml

Sentinel · KQL

Run this as a search.

DeviceProcessEvents| where ((ProcessCommandLine contains "vssadmin" and ProcessCommandLine contains "delete shadows") or (ProcessCommandLine contains "wbadmin" and ProcessCommandLine contains "delete") or (ProcessCommandLine contains "shadowcopy" and ProcessCommandLine contains "delete") or (ProcessCommandLine contains "bcdedit" and ProcessCommandLine contains "recoveryenabled") or (ProcessCommandLine contains "reagentc" and ProcessCommandLine contains "/disable") or ProcessCommandLine contains "diskshadow.exe")

Splunk · SPL

Run this as a search.

index=* ((CommandLine="*vssadmin*" AND CommandLine="*delete shadows*") OR (CommandLine="*wbadmin*" AND CommandLine="*delete*") OR (CommandLine="*shadowcopy*" AND CommandLine="*delete*") OR (CommandLine="*bcdedit*" AND CommandLine="*recoveryenabled*") OR (CommandLine="*reagentc*" AND CommandLine="*/disable*") OR CommandLine="*diskshadow.exe*")

Elastic · ES|QL

Run this as a search.

FROM logs-*| WHERE ((TO_LOWER(process.command_line) LIKE "*vssadmin*" AND TO_LOWER(process.command_line) LIKE "*delete shadows*") OR (TO_LOWER(process.command_line) LIKE "*wbadmin*" AND TO_LOWER(process.command_line) LIKE "*delete*") OR (TO_LOWER(process.command_line) LIKE "*shadowcopy*" AND TO_LOWER(process.command_line) LIKE "*delete*") OR (TO_LOWER(process.command_line) LIKE "*bcdedit*" AND TO_LOWER(process.command_line) LIKE "*recoveryenabled*") OR (TO_LOWER(process.command_line) LIKE "*reagentc*" AND TO_LOWER(process.command_line) LIKE "*/disable*") OR TO_LOWER(process.command_line) LIKE "*diskshadow.exe*")

Wazuh · XML rule

Deploy to your manager — this is a rule, not a search.

<group name="sigma,windows,process_creation,">  <!-- Rule ids must be unique on your manager; 100000+ is the user range. -->  <rule id="100000" level="5">    <!-- Set <if_sid> to the decoder/base rule for windows so this only evaluates relevant events. -->    <field name="CommandLine" type="pcre2">(?i)((?=.*(?:vssadmin))(?=.*(?:delete shadows)).*|(?=.*(?:wbadmin))(?=.*(?:delete)).*|(?=.*(?:shadowcopy))(?=.*(?:delete)).*|(?=.*(?:bcdedit))(?=.*(?:recoveryenabled)).*|(?=.*(?:reagentc))(?=.*(?:/disable)).*|diskshadow\.exe)</field>    <description>Native Windows utility deletes shadow copies or disables recovery</description>    <mitre>      <id>T1490</id>    </mitre>  </rule></group>

At a glance

Logsource: process_creation / windows
Level: low
Category: impact_destruction
Sigma status: experimental
Backends: 4 of 4 rendered
Updated: 30 Aug 2026
Rule ID: b6eaab79-935e-4c17-8816-43b3e8ee8212

ATT&CKT1490

T1490Inhibit System Recovery

ATT&CK® is a registered trademark of The MITRE Corporation. These mappings are the rule author’s, and are neither reviewed nor endorsed by MITRE.

Lessonimpact destruction

impact destruction

01 · What this rule detects

The work an operator does to make recovery impossible before, or while, destroying data — deleting volume shadow copies, wiping backup catalogs, disabling Windows recovery and boot repair, and deleting or overwriting files recursively. Most of it happens in a short burst immediately before encryption, which is why the precursors are the part worth detecting: by the time file modification volume is the signal, the decision has already been made for you. This overlaps deliberately with log clearing — the same burst usually destroys evidence and recovery together — but keep the two rules apart, because they point at different questions.

02 · Telemetry you need

Process creation with full command lines — Sysmon EventID 1, or Security 4688 with Audit Process Creation and the command-line inclusion policy; without the second policy you see that vssadmin ran and nothing about what it did
The utilities themselves: vssadmin, wmic shadowcopy, wbadmin, bcdedit, cipher, and the PowerShell and WMI equivalents that never touch a command-line binary
Sysmon EventID 23 and 26 (FileDelete and FileDeleteDetected) — not in the default configuration, and the archiving variant needs disk space budgeted for it
Service and provider activity for the Volume Shadow Copy service, and the backup product's own logs, which record deletion the operating system does not
Security 4663 for delete access on protected shares — Audit Object Access plus a SACL, off by default and inert without the SACL

03 · How the logic works

These command lines are short, fixed and close to unique, which makes this one of the few categories where string matching against the command line is the right primary approach rather than a fallback. Structure each as image AND destructive verb: matching vssadmin alone catches every backup product listing shadows, whereas vssadmin with delete does not. Allow for argument reordering, abbreviation and the several spellings of the same operation, and remember that the same effect is reachable through WMI and the COM interfaces without running the utility at all — so a rule set that names only the executables has a hole in it that any competent tooling walks through. The mass-encryption half is a rate problem: file modifications per process per minute, which Sigma cannot express and which belongs in the correlation layer.

04 · Common false positives

Backup software managing its own shadow storage and pruning old copies — Veeam, Acronis, Windows Server Backup and the built-in scheduled tasks
Disk cleanup and storage reclamation removing shadow copies when a volume fills
Imaging, provisioning and task sequences that use bcdedit and reset recovery configuration by design
Non-persistent VDI and lab rebuild workflows that discard machine state on every cycle
Developers and build systems recursively deleting output directories

05 · Detection maturity

Tier 1 — starting point: Matches vssadmin and wbadmin deletion command lines.
Tier 2 — tuned: Covers the WMI and PowerShell routes and boot configuration tampering, with backup hosts and maintenance windows excluded.
Tier 3 — correlated: Correlates recovery destruction with log clearing, service stops and file modification rate from the same host and process tree.

Tuning & false positivesexperimental · 5 declared

experimental (current stage)
test
stable

Written and reasoned about, but not yet run against real telemetry. Expect to tune it before trusting it.

Tuning tips

This should be a near-silent category. If it is noisy, find out what is deleting recovery points routinely and fix that rather than filtering it
Never exclude by account — the accounts used here are administrative by definition, which is the point
Scope exclusions to the specific backup hosts and their maintenance windows, and revisit them when the backup product changes
Alert on failed attempts as well as successful ones; a denied shadow deletion is the same intent and better news
Escalate hard on the combination — shadow deletion, log clearing and service stops from one host inside a few minutes is a different alert from any of them alone

Declared by the author

VSS-aware backup software. diskshadow.exe is Microsoft's own tool for scripting application-consistent shadow copies, and commercial backup agents and SQL Server backup jobs invoke it and vssadmin routinely — on a backup server this can be the loudest match here by a wide margin, since the rule sees the tool's launch and not which script it was handed.
Windows servicing. The setup process for a major Windows feature update runs reagentc /disable to free the recovery partition before it applies the update and re-enables WinRE afterward, so any host on a normal patch cadence produces this command line during its update window without anything malicious happening.
OS deployment and imaging pipelines that disable WinRE with reagentc, clear shadow copies with vssadmin, or reset bcdedit recovery flags as documented steps before capturing or laying down a reference image.
Administrators freeing disk space with vssadmin, retiring an old system state backup with wbadmin, or disabling the automatic repair loop with bcdedit while troubleshooting a boot problem, or running diskshadow.exe interactively to inspect or create a shadow copy.
OEM factory-recovery-partition utilities (Dell SupportAssist OS Recovery, HP Recovery Manager, Lenovo OneKey Recovery) and AV/EDR post-incident remediation tooling that call reagentc /disable while rebuilding or reimaging the recovery partition.

Noise check0 of 30 fired

Fires on none of the 30 ordinary behaviours the baseline holds for this log type. That is not a precision guarantee: it means only not caught by these 30 behaviours, and the next ordinary behaviour nobody wrote down may still match.

Run live against 65 hand-written events of ordinary corporate activity — backup agents, software distribution, patching, helpdesk scripts, EDR. It says nothing about how often the rule would fire in production, which is the number that actually exhausts an analyst.

Verification1 run

Not verified

Siemphony benign baseline
completed
Siemphony IR · 3 Sept 2026
No events matched, so this run proves nothing either way.

Test it yourselfin your browser

Runs here in your browser against public attack recordings. A preview — not the verification badge.

Recordings of T1490, evaluated against their process_creation events.

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Native Windows utility deletes shadow copies or disables recovery

The detection

detection.yml

Sentinel · KQL

Splunk · SPL

Elastic · ES|QL

Wazuh · XML rule

Community

Verdicts from engineers who deployed it