# [CRIT] New GreatXML Exploit Bypasses Windows BitLocker via Recovery Partition XML Files

**Source:** The Hacker News
**Published:** 2026-06-11
**Article:** https://thehackernews.com/2026/06/new-greatxml-exploit-bypasses-windows.html

## Threat Profile

New GreatXML Exploit Bypasses Windows BitLocker via Recovery Partition XML Files 
 Ravie Lakshmanan  Jun 11, 2026 Endpoint Security / Vulnerability 
Security researcher Chaotic Eclipse (aka Nightmare-Eclipse and MSNightmare) has released a new Windows BitLocker bypass dubbed GreatXML , a day after they published an exploit for Microsoft Defender.
"This was an accidental discovery, it took a total of 4 hours to find this," the researcher said in a post on Blogger. "If you ever attempted to use …

## Indicators of Compromise (high-fidelity only)

- **CVE:** `CVE-2026-45585`

## MITRE ATT&CK Techniques

- **T1071.001** — Web Protocols
- **T1071.004** — DNS
- **T1190** — Exploit Public-Facing Application
- **T1528** — Steal Application Access Token
- **T1098.001** — Account Manipulation: Additional Cloud Credentials
- **T1566.002** — Spearphishing Link
- **T1204.001** — User Execution: Malicious Link
- **T1059.001** — PowerShell
- **T1204.004** — User Execution: Malicious Copy and Paste
- **T1195.002** — Compromise Software Supply Chain
- **T1542.005** — Bootkit: TFTP Boot / Pre-OS Boot
- **T1112** — Modify Registry
- **T1027** — Obfuscated Files or Information
- **T1542.005** — Pre-OS Boot: TFTP Boot
- **T1552.004** — Unsecured Credentials: Private Keys
- **T1486** — Data Encrypted for Impact (defensive removal)
- **T1078.003** — Valid Accounts: Local Accounts
- **T1518.001** — Software Discovery: Security Software Discovery
- **T1562.001** — Impair Defenses: Disable or Modify Tools
- **T1542.001** — Pre-OS Boot: System Firmware

## Kill chain phases observed

_(none detected from narrative keywords)_

## Recommended hunts

### Write of unattend.xml or ReAgent.xml to system recovery partition (GreatXML staging)

`UC_42_6` · phase: **weapon** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=true count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Filesystem where (Filesystem.file_name="unattend.xml" OR Filesystem.file_name="ReAgent.xml") (Filesystem.file_path="*\\Recovery\\*" OR Filesystem.file_path="*\\WindowsRE\\*" OR Filesystem.file_path="*\\EFI\\Microsoft\\Recovery\\*" OR Filesystem.file_path="*\\System Volume Information\\Recovery\\*") by Filesystem.dest Filesystem.user Filesystem.file_name Filesystem.file_path Filesystem.process_name | `drop_dm_object_name(Filesystem)` | where NOT match(user,"\$$") | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
```

**Defender KQL:**
```kql
DeviceFileEvents
| where Timestamp > ago(7d)
| where FileName in~ ("unattend.xml", "ReAgent.xml")
| where FolderPath has_any (@"\Recovery\", @"\WindowsRE\", @"\EFI\Microsoft\Recovery", @"\System Volume Information\Recovery")
| where not(InitiatingProcessAccountName endswith "$")
| where InitiatingProcessFileName !in~ ("TrustedInstaller.exe", "DISM.exe", "setup.exe")
| project Timestamp, DeviceName, FileName, FolderPath, ActionType, InitiatingProcessFileName, InitiatingProcessFolderPath, InitiatingProcessCommandLine, InitiatingProcessAccountName, InitiatingProcessParentFileName, SHA256
| order by Timestamp desc
```

### reagentc.exe invocation enabling or remounting WinRE before reboot (GreatXML precondition)

`UC_42_7` · phase: **install** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=true count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name="reagentc.exe" (Processes.process="*/enable*" OR Processes.process="*/setreimage*" OR Processes.process="*/mountrec*" OR Processes.process="*/boottore*") by Processes.dest Processes.user Processes.parent_process_name Processes.process | `drop_dm_object_name(Processes)` | where NOT match(user,"\$$") | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where FileName =~ "reagentc.exe"
| where ProcessCommandLine has_any ("/enable", "/setreimage", "/mountrec", "/boottore", "/setbootshelllink")
| where not(AccountName endswith "$")
| where InitiatingProcessFileName !in~ ("TrustedInstaller.exe", "DISM.exe", "WindowsUpdateBox.exe")
| project Timestamp, DeviceName, AccountName, ProcessCommandLine, FolderPath, InitiatingProcessFileName, InitiatingProcessCommandLine, InitiatingProcessParentFileName, IsInitiatingProcessRemoteSession
| order by Timestamp desc
```

### BitLocker tamper attempt via manage-bde or BitLocker PowerShell after WinRE shell access

`UC_42_8` · phase: **actions** · confidence: **High** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=true count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.process_name="manage-bde.exe" Processes.process IN ("*-off*","*-unlock*","*-protectors*","*-disable*","*-forcerecovery*")) OR (Processes.process_name IN ("powershell.exe","pwsh.exe") (Processes.process="*Disable-BitLocker*" OR Processes.process="*Remove-BitLockerKeyProtector*" OR Processes.process="*Suspend-BitLocker*")) by Processes.dest Processes.user Processes.parent_process_name Processes.process | `drop_dm_object_name(Processes)` | where NOT match(user,"\$$") | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
```

**Defender KQL:**
```kql
let bde_native = DeviceProcessEvents
    | where Timestamp > ago(7d)
    | where FileName =~ "manage-bde.exe"
    | where ProcessCommandLine has_any ("-off", "-unlock", "-protectors", "-disable", "-forcerecovery");
let bde_ps = DeviceProcessEvents
    | where Timestamp > ago(7d)
    | where FileName in~ ("powershell.exe", "pwsh.exe")
    | where ProcessCommandLine has_any ("Disable-BitLocker", "Remove-BitLockerKeyProtector", "Suspend-BitLocker", "Lock-BitLocker");
union bde_native, bde_ps
| where not(AccountName endswith "$")
| project Timestamp, DeviceName, AccountName, FileName, ProcessCommandLine, InitiatingProcessFileName, InitiatingProcessParentFileName, IsInitiatingProcessRemoteSession
| order by Timestamp desc
```

### Defender Offline Scan initiation - GreatXML vulnerability precondition

`UC_42_9` · phase: **recon** · confidence: **Medium** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=true count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name="MpCmdRun.exe" (Processes.process="*OfflineScan*" OR Processes.process="*-Scan -ScheduleJob*" OR Processes.process="*-WaitOnTask*") by Processes.dest Processes.user Processes.parent_process_name Processes.process | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
```

**Defender KQL:**
```kql
let offlinescan_proc = DeviceProcessEvents
    | where Timestamp > ago(30d)
    | where FileName =~ "MpCmdRun.exe"
    | where ProcessCommandLine has_any ("OfflineScan", "-Scan -ScheduleJob", "-WaitOnTask")
    | project Timestamp, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessFileName, Signal="proc";
let offlinescan_reg = DeviceRegistryEvents
    | where Timestamp > ago(30d)
    | where RegistryKey has @"\Microsoft\Windows Defender\Scan"
    | where RegistryValueName has_any ("OfflineScanRun", "OfflineScanRequired")
    | project Timestamp, DeviceName, AccountName=InitiatingProcessAccountName, ProcessCommandLine=InitiatingProcessCommandLine, InitiatingProcessFileName, Signal="reg";
union offlinescan_proc, offlinescan_reg
| order by Timestamp desc
```

### bcdedit recovery-sequence modification consistent with GreatXML WinRE pivot

`UC_42_10` · phase: **install** · confidence: **Medium** · AI-generated for this article

**Splunk SPL (CIM):**
```spl
| tstats summariesonly=true count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name="bcdedit.exe" (Processes.process="*/set*recoverysequence*" OR Processes.process="*/set*recoveryenabled*" OR Processes.process="*/copy*recoverysequence*" OR Processes.process="*/create*" OR Processes.process="*/import*") by Processes.dest Processes.user Processes.parent_process_name Processes.process | `drop_dm_object_name(Processes)` | where NOT match(user,"\$$") | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where FileName =~ "bcdedit.exe"
| where ProcessCommandLine has_any ("recoverysequence", "recoveryenabled", "/copy", "/create", "/import", "bootsequence")
| where not(AccountName endswith "$")
| where InitiatingProcessFileName !in~ ("TrustedInstaller.exe", "DISM.exe", "WindowsUpdateBox.exe", "setup.exe")
| project Timestamp, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessFileName, InitiatingProcessCommandLine, InitiatingProcessParentFileName, IsInitiatingProcessRemoteSession
| order by Timestamp desc
```

### Beaconing — periodic outbound to small set of destinations

`UC_BEACONING` · phase: **c2** · confidence: **Medium**

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count, values(All_Traffic.dest_port) AS ports
    from datamodel=Network_Traffic.All_Traffic
    where All_Traffic.action="allowed" AND All_Traffic.dest_category!="internal"
    by _time span=10s, All_Traffic.src, All_Traffic.dest
| `drop_dm_object_name(All_Traffic)`
| streamstats current=f last(_time) AS prev_time by src, dest
| eval delta = _time - prev_time
| stats avg(delta) AS avg_delta stdev(delta) AS sd_delta count by src, dest
| where count > 30 AND sd_delta < 5 AND avg_delta>=30 AND avg_delta<=600
| sort - count
```

**Defender KQL:**
```kql
DeviceNetworkEvents
| where Timestamp > ago(1d)
| where RemoteIPType == "Public" and ActionType == "ConnectionSuccess"
| project DeviceName, RemoteIP, RemotePort, Timestamp
| sort by DeviceName asc, RemoteIP asc, RemotePort asc, Timestamp asc
| extend prev_dev = prev(DeviceName, 1), prev_ip = prev(RemoteIP, 1),
         prev_port = prev(RemotePort, 1), prev_ts = prev(Timestamp, 1)
| where DeviceName == prev_dev and RemoteIP == prev_ip and RemotePort == prev_port
| extend delta_sec = datetime_diff('second', Timestamp, prev_ts)
| summarize conn_count = count(), avg_delta = avg(delta_sec), stdev_delta = stdev(delta_sec)
    by DeviceName, RemoteIP, RemotePort
| where conn_count > 30 and avg_delta between (30.0 .. 600.0) and stdev_delta < 5.0
| order by conn_count desc
```

### OAuth consent / suspicious app grant

`UC_OAUTH_ABUSE` · phase: **actions** · confidence: **High**

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime
    from datamodel=Authentication.Authentication
    where Authentication.action="success"
      AND Authentication.signature IN (
        "Consent to application",
        "Add app role assignment grant to user",
        "Add OAuth2PermissionGrant",
        "Add delegated permission grant")
    by Authentication.user, Authentication.app, Authentication.src, Authentication.signature
| `drop_dm_object_name(Authentication)`
```

**Defender KQL:**
```kql
CloudAppEvents
| where Timestamp > ago(7d)
| where ActionType in ("Consent to application.","Add OAuth2PermissionGrant.","Add delegated permission grant.")
| project Timestamp, AccountObjectId, AccountDisplayName, ActivityType,
          ActivityObjects, IPAddress, UserAgent
```

### Phishing-link click correlated to endpoint execution

`UC_PHISH_LINK` · phase: **delivery** · confidence: **High**

**Splunk SPL (CIM):**
```spl
``` Phishing-link click that drives endpoint execution within 60s ```
| tstats `summariesonly` earliest(_time) AS click_time
    from datamodel=Web
    where Web.action="allowed"
    by Web.src, Web.user, Web.dest, Web.url
| `drop_dm_object_name(Web)`
| rename user AS recipient, dest AS clicked_domain, url AS clicked_url
| join type=inner recipient
    [| tstats `summariesonly` count
         from datamodel=Email.All_Email
         where All_Email.action="delivered" AND All_Email.url!="-"
         by All_Email.recipient, All_Email.src_user, All_Email.url, All_Email.subject
     | `drop_dm_object_name(All_Email)`
     | rex field=url "https?://(?<email_domain>[^/]+)"
     | rename recipient AS recipient]
| join type=inner src
    [| tstats `summariesonly` earliest(_time) AS exec_time
         values(Processes.process) AS exec_cmd, values(Processes.process_name) AS exec_proc
         from datamodel=Endpoint.Processes
         where Processes.parent_process_name IN ("chrome.exe","msedge.exe","firefox.exe",
                                                   "outlook.exe","brave.exe","arc.exe")
           AND Processes.process_name IN ("powershell.exe","pwsh.exe","cmd.exe","mshta.exe",
                                            "rundll32.exe","regsvr32.exe","wscript.exe",
                                            "cscript.exe","bitsadmin.exe","certutil.exe",
                                            "curl.exe","wget.exe")
         by Processes.dest, Processes.user
     | `drop_dm_object_name(Processes)`
     | rename dest AS src]
| eval delta_sec = exec_time - click_time
| where delta_sec >= 0 AND delta_sec <= 60
| table click_time, exec_time, delta_sec, recipient, src, src_user, subject,
        clicked_domain, clicked_url, exec_proc, exec_cmd
| sort - click_time
```

**Defender KQL:**
```kql
// Phishing-link click that drives endpoint execution within 60s.
// Far higher fidelity than "every clicked URL" — most legitimate clicks
// never spawn a non-browser child process, so the join eliminates the
// 99% of noise that makes a raw click query unactionable.
let LookbackDays = 7d;
let SuspectClicks = UrlClickEvents
    | where Timestamp > ago(LookbackDays)
    | where AccountName !endswith "$"
    | where ActionType in ("ClickAllowed","ClickedThrough")
    | join kind=inner (
        EmailEvents
        | where Timestamp > ago(LookbackDays)
        | where DeliveryAction == "Delivered"
        | where EmailDirection == "Inbound"
        | project NetworkMessageId, Subject, SenderFromAddress, SenderFromDomain,
                  RecipientEmailAddress, EmailTimestamp = Timestamp
      ) on NetworkMessageId
    | join kind=leftouter (
        EmailUrlInfo | project NetworkMessageId, Url, UrlDomain
      ) on NetworkMessageId, Url
    | project ClickTime = Timestamp, AccountUpn, IPAddress, Url, UrlDomain,
              Subject, SenderFromAddress, SenderFromDomain, RecipientEmailAddress,
              ActionType;
// Correlate to a non-browser child process spawned within 60 seconds on
// the recipient's device.
DeviceProcessEvents
| where Timestamp > ago(LookbackDays)
| where InitiatingProcessFileName in~ ("chrome.exe","msedge.exe","firefox.exe",
                                         "outlook.exe","brave.exe","arc.exe")
| where FileName in~ ("powershell.exe","pwsh.exe","cmd.exe","mshta.exe",
                        "rundll32.exe","regsvr32.exe","wscript.exe","cscript.exe",
                        "bitsadmin.exe","certutil.exe","curl.exe","wget.exe")
| join kind=inner SuspectClicks on $left.AccountName == $right.AccountUpn
| where Timestamp between (ClickTime .. ClickTime + 60s)
| project ClickTime, ProcessTime = Timestamp,
          DelaySec = datetime_diff('second', Timestamp, ClickTime),
          DeviceName, AccountName, RecipientEmailAddress, SenderFromAddress,
          Subject, Url, UrlDomain, ActionType,
          FileName, ProcessCommandLine, InitiatingProcessFileName
| order by ClickTime desc
```

### Fake CAPTCHA / clipboard-injected PowerShell (ClickFix / FakeCaptcha)

`UC_FAKECAPTCHA` · phase: **exploit** · confidence: **High**

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime
    from datamodel=Endpoint.Processes
    where Processes.parent_process_name IN ("explorer.exe","RuntimeBroker.exe")
      AND Processes.process_name IN ("powershell.exe","pwsh.exe","mshta.exe")
      AND (Processes.process="*iex*" OR Processes.process="*Invoke-Expression*"
        OR Processes.process="*FromBase64*" OR Processes.process="*DownloadString*"
        OR Processes.process="*hxxp*" OR Processes.process="*curl*" OR Processes.process="*wget*")
    by Processes.dest, Processes.user, Processes.process, Processes.parent_process_name
| `drop_dm_object_name(Processes)`
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where AccountName !endswith "$"
| where InitiatingProcessFileName in~ ("explorer.exe","RuntimeBroker.exe")
| where FileName in~ ("powershell.exe","pwsh.exe","mshta.exe")
| where ProcessCommandLine matches regex @"(?i)(iex|invoke-expression|frombase64|downloadstring|hxxp|curl |wget )"
| project Timestamp, DeviceName, AccountName, ProcessCommandLine, InitiatingProcessCommandLine
```

### Trusted vendor binary / installer launching unusual children

`UC_SUPPLY_CHAIN` · phase: **exploit** · confidence: **Medium**

**Splunk SPL (CIM):**
```spl
| tstats `summariesonly` count min(_time) as firstTime max(_time) as lastTime
    from datamodel=Endpoint.Processes
    where Processes.parent_process_name IN ("setup.exe","installer.exe","update.exe")
      AND Processes.process_name IN ("powershell.exe","cmd.exe","rundll32.exe","regsvr32.exe","mshta.exe","wscript.exe","cscript.exe","wmic.exe","bitsadmin.exe")
    by Processes.dest, Processes.user, Processes.parent_process_name, Processes.process_name, Processes.process
| `drop_dm_object_name(Processes)`
```

**Defender KQL:**
```kql
DeviceProcessEvents
| where Timestamp > ago(7d)
| where AccountName !endswith "$"
| where InitiatingProcessFileName in~ ("setup.exe","installer.exe","update.exe")
| where FileName in~ ("powershell.exe","cmd.exe","rundll32.exe","regsvr32.exe","mshta.exe","wscript.exe","cscript.exe","wmic.exe","bitsadmin.exe")
| project Timestamp, DeviceName, AccountName, InitiatingProcessFileName, FileName, ProcessCommandLine
```

### IOC-driven hunts (use shared templates)

These are standard IOC-substitution hunts — the canonical SPL and KQL live once in [`_TEMPLATES.md`](../_TEMPLATES.md), so we don't repeat the same boilerplate on every CVE / hash / network-IOC briefing.

- **Asset exposure — vulnerability matches article CVE(s)** ([template](../_TEMPLATES.md#asset-exposure)) — phase: **recon**, confidence: **High**
  - CVE(s): `CVE-2026-45585`


## Why this matters

Severity classified as **CRIT** based on: CVE present, 11 use case(s) fired, 20 technique(s) inferred. Read the full article for actor attribution, tooling details, and any defanged IOCs in the body that aren't visible in the RSS summary.