S1178: ShrinkLocker
ShrinkLocker is a VBS-based malicious script that leverages the legitimate Bitlocker application to encrypt files on victim systems for ransom. ShrinkLocker functions by using Bitlocker to encrypt files, then renames impacted drives to the adversary’s contact email address to facilitate communication for the ransom payment.[1][2]
Security context for executives and security teams
S1178: ShrinkLocker describes [ShrinkLocker](https://attack.mitre.org/software/S1178) is a VBS-based malicious script that leverages the legitimate Bitlocker application to encrypt files on victim systems for ransom. [ShrinkLocker](https://attack.mitre.org/software/S1178) functions by using Bitlocker to encrypt files, then renames impacted drives to the adversary’s contact email address to facilitate communication for the ransom payment.(Citation: Kaspersky ShrinkLocker 2024)(Citation: Splunk ShrinkLocker 2024)
Executive priority
S1178: ShrinkLocker is an official MITRE ATT&CK software. Glexia treats it as defensive behavior context for prioritizing monitoring, control validation, and response planning without using the object by itself as an attribution claim.
Technical view
Security teams should validate S1178: ShrinkLocker by reviewing the official ATT&CK relationships, mapped tactics (the mapped ATT&CK tactic context), supported platforms (Windows), and available local telemetry before making detection or mitigation decisions.
Likely telemetry
- Official ATT&CK relationships and object metadata
- Network, endpoint, and security-tool telemetry
Detection direction
- Validate whether S1178: ShrinkLocker appears in your detection coverage and tabletop scenarios.
- Use the object to align executive risk language with SOC, incident response, and detection engineering work.
- Do not treat ATT&CK relationship context as attribution without corroborating evidence.
Mitigation priorities
- Map the object to existing controls and identify missing telemetry or response ownership.
- Prioritize mitigations that reduce exposure on the listed platforms and tactics.
- Review adjacent ATT&CK relationships before changing policy, detections, or reporting language.
Additional notes and limits
Baseline Glexia take generated from the official MITRE ATT&CK STIX object, source hash, tactics, platforms, and detection fields. It is safe to replace with a richer model-generated take for the same source hash later.
This baseline take is source-grounded and schema-validated, but it does not include environment-specific telemetry, incident evidence, or threat-intelligence corroboration.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
ShrinkLocker
ShrinkLocker is a VBS-based malicious script that leverages the legitimate Bitlocker application to encrypt files on victim systems for ransom. ShrinkLocker functions by using Bitlocker to encrypt files, then renames impacted drives to the adversary’s contact email address to facilitate communication for the ransom payment.[1][2]
How security teams should use this page
Treat this object as behavior context, not an attribution claim. Validate the related groups, software, data sources, and mitigations against official ATT&CK relationships and your own telemetry before making control-coverage decisions.
Techniques used
This mirrors the MITRE pattern of making group, software, campaign, and technique relationships scannable. Relationship notes come from mirrored ATT&CK relationship text when available.
| Domain | ID | Name | Relationship / procedure |
|---|---|---|---|
| Enterprise | T1124 | System Time Discovery | ShrinkLocker retrieves a system timestamp that is used in generating an encryption key.[2] |
| Enterprise | T1491.001 | Internal DefacementSub-technique | ShrinkLocker renames disk labels on victim hosts to the threat actor's email address to enable the victim to contact the threat actor for ransom negotiation.[1][2] |
| Enterprise | T1082 | System Information Discovery | ShrinkLocker uses WMI queries to gather various information about the victim machine and operating system.[1][2] |
| Enterprise | T1059.005 | Visual BasicSub-technique | ShrinkLocker is a VisualBasic script (VBS) object that calls multiple other operating system functions during execution.[1][2] |
| Enterprise | T1059.001 | PowerShellSub-technique | ShrinkLocker uses PowerShell to disable protectors used to secure the BitLocker encryption key on victim machines and then delete the key from the system.[1] |
| Enterprise | T1112 | Modify Registry | ShrinkLocker modifies various registry keys associated with system logon and BitLocker functionality to effectively lock-out users following disk encryption.[1][2] |
| Enterprise | T1685.005 | Clear Windows Event LogsSub-technique | ShrinkLocker calls Wevtutil to clear the Windows PowerShell and Microsoft-Windows-Powershell/Operational logs.[1] |
| Enterprise | T1047 | Windows Management Instrumentation | ShrinkLocker uses WMI to query information about the victim operating system.[1] |
| Enterprise | T1102 | Web Service | ShrinkLocker uses a subdomain on the legitimate Cloudflare resource "trycloudflare[.]com" to obfuscate the threat actor's actual address and to tunnel information sent from victim systems.[1] |
| Enterprise | T1486 | Data Encrypted for Impact | ShrinkLocker uses the legitimate BitLocker application to encrypt victim files for ransom.[1][2] |
| Enterprise | T1561.002 | Disk Structure WipeSub-technique | ShrinkLocker has used Diskpart to format newly-created partitions.[2] |
| Enterprise | T1041 | Exfiltration Over C2 Channel | ShrinkLocker will exfiltrate victim system information along with the encryption key via an HTTP POST.[1][2] |
| Enterprise | T1529 | System Shutdown/Reboot | ShrinkLocker can restart the victim system if it encounters an error during execution, and will forcibly shutdown the system following encryption to lock out victim users.[1] |
| Enterprise | T1685 | Disable or Modify Tools | ShrinkLocker disables protectors used to secure the BitLocker encryption key on victim systems.[1][2] |
| Enterprise | T1016 | System Network Configuration Discovery | ShrinkLocker captures the IP address of the victim system and sends this to the attacker following encryption.[1] |
| Enterprise | T1686 | Disable or Modify System Firewall | ShrinkLocker turns on the system firewall and deletes all of its rules during execution.[1][2] |
| Enterprise | T1480 | Execution Guardrails | ShrinkLocker will exit its "main" function if the victim domain name does not match provided criteria.[2] |
| Enterprise | T1070.004 | File DeletionSub-technique | ShrinkLocker can delete itself depending on various checks performed during execution.[1] |
| Enterprise | T1485 | Data Destruction | ShrinkLocker can initiate a destructive payload depending on the operating system check through resizing and reformatting portions of the victim machine's disk, leading to system instability and potential data corruption.[2] |
| Enterprise | T1057 | Process Discovery | ShrinkLocker checks whether the Bitlocker Drive Encryption Tools service is running.[2] |
| Enterprise | T1071.001 | Web ProtocolsSub-technique | ShrinkLocker uses HTTP POST requests to communicate victim information back to the threat actor.[1] |
All related ATT&CK context
Object version and sync metadata
The fields below describe the current mirrored snapshot. When Glexia retains multiple ATT&CK source imports, you can open the table to compare the same object across releases (hashes and MITRE timestamps). For MITRE’s own release notes and roadmap, see ATT&CK resources — Updates.
Imported snapshots across ATT&CK releases(3)
| Release | Bundle imported | Object version | Modified | Status | Raw hash |
|---|---|---|---|---|---|
| 20.0 | 1.1 | Current bundle | 7e5821741504… | ||
| 19.2 | 1.1 | Older bundle | 7e5821741504… | ||
| 19.1 | 1.1 | Older bundle | 7e5821741504… |
Mirrored ATT&CK source object
The raw object is retained through the mirrored ATT&CK source bundle and object hash. The raw endpoint returns the exact object from the mirrored bundle when available.
External references and citations
MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.
- [1]Kaspersky ShrinkLocker 2024
Cristian Souza, Eduardo Ovalle, Ashley Muñoz, & Christopher Zachor. (2024, May 23). ShrinkLocker: Turning BitLocker into ransomware. Retrieved December 7, 2024.
Open source URL - [2]Splunk ShrinkLocker 2024
Splunk Threat Research Team , Teoderick Contreras. (2024, September 5). ShrinkLocker Malware: Abusing BitLocker to Lock Your Data. Retrieved December 7, 2024.
Open source URL - [3]mitre-attackS1178Open source URL
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