S1053: AvosLocker
AvosLocker is ransomware written in C++ that has been offered via the Ransomware-as-a-Service (RaaS) model. It was first observed in June 2021 and has been used against financial services, critical manufacturing, government facilities, and other critical infrastructure sectors in the United States. As of March 2022, AvosLocker had also been used against organizations in Belgium, Canada, China, Germany, Saudi Arabia, Spain, Syria, Taiwan, Turkey, the United Arab Emirates, and the United Kingdom.[1][2][3]
Security context for executives and security teams
S1053: AvosLocker describes [AvosLocker](https://attack.mitre.org/software/S1053) is ransomware written in C++ that has been offered via the Ransomware-as-a-Service (RaaS) model. It was first observed in June 2021 and has been used against financial services, critical manufacturing, government facilities, and other critical infrastructure sectors in the United States. As of March 2022, [AvosLocker](https://attack.mitre.org/software/S1053) had also been used against organizations in Belgium, Canada, China, Germany, Saudi Arabia, Spain, Syria, ...
Executive priority
S1053: AvosLocker 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 S1053: AvosLocker by reviewing the official ATT&CK relationships, mapped tactics (the mapped ATT&CK tactic context), supported platforms (Linux, 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 S1053: AvosLocker 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.
AvosLocker
AvosLocker is ransomware written in C++ that has been offered via the Ransomware-as-a-Service (RaaS) model. It was first observed in June 2021 and has been used against financial services, critical manufacturing, government facilities, and other critical infrastructure sectors in the United States. As of March 2022, AvosLocker had also been used against organizations in Belgium, Canada, China, Germany, Saudi Arabia, Spain, Syria, Taiwan, Turkey, the United Arab Emirates, and the United Kingdom.[1][2][3]
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 | T1106 | Native API | AvosLocker has used a variety of Windows API calls, including `NtCurrentPeb` and `GetLogicalDrives`.[1] |
| Enterprise | T1688 | Safe Mode Boot | AvosLocker can restart a compromised machine in safe mode.[2]CitationCosta AvosLocker May 2022 |
| Enterprise | T1486 | Data Encrypted for Impact | AvosLocker has encrypted files and network resources using AES-256 and added an `.avos`, `.avos2`, or `.AvosLinux` extension to filenames.[1][2]CitationCisco Talos Avos Jun 2022[3] |
| Enterprise | T1547.001 | Registry Run Keys / Startup FolderSub-technique | AvosLocker has been executed via the `RunOnce` Registry key to run itself on safe mode.[2] |
| Enterprise | T1140 | Deobfuscate/Decode Files or Information | AvosLocker has deobfuscated XOR-encoded strings.[1] |
| Enterprise | T1027.007 | Dynamic API ResolutionSub-technique | AvosLocker has used obfuscated API calls that are retrieved by their checksums.[1] |
| Enterprise | T1083 | File and Directory Discovery | AvosLocker has searched for files and directories on a compromised network.[1][2] |
| Enterprise | T1036.008 | Masquerade File TypeSub-technique | AvosLocker has been disguised as a .jpg file.[2] |
| Enterprise | T1564.003 | Hidden WindowSub-technique | AvosLocker has hidden its console window by using the `ShowWindow` API function.[1] |
| Enterprise | T1489 | Service Stop | AvosLocker has terminated specific processes before encryption.[1] |
| Enterprise | T1135 | Network Share Discovery | AvosLocker has enumerated shared drives on a compromised network.[1][3] |
| Enterprise | T1027 | Obfuscated Files or Information | AvosLocker has used XOR-encoded strings.[1] |
| Enterprise | T1124 | System Time Discovery | AvosLocker has checked the system time before and after encryption.[1] |
| Enterprise | T1057 | Process Discovery | AvosLocker has discovered system processes by calling `RmGetList`.[1] |
| Enterprise | T1529 | System Shutdown/Reboot | AvosLocker’s Linux variant has terminated ESXi virtual machines.[2] |
Groups, software, and campaigns
C0018: C0018
C0018 was a month-long ransomware intrusion that successfully deployed AvosLocker onto a compromised network. The unidentified actors gained initial access to the victim network through an exposed server and used a variety of open-source tools prior to executing AvosLocker.[1][2]
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(2)
| Release | Bundle imported | Object version | Modified | Status | Raw hash |
|---|---|---|---|---|---|
| 19.2 | 1.0 | Current bundle | fa2afd65c745… | ||
| 19.1 | 1.0 | Older bundle | fa2afd65c745… |
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]Malwarebytes AvosLocker Jul 2021
Hasherezade. (2021, July 23). AvosLocker enters the ransomware scene, asks for partners. Retrieved January 11, 2023.
Open source URL - [2]Trend Micro AvosLocker Apr 2022
Trend Micro Research. (2022, April 4). Ransomware Spotlight AvosLocker. Retrieved January 11, 2023.
Open source URL - [3]Joint CSA AvosLocker Mar 2022
FBI, FinCEN, Treasury. (2022, March 17). Indicators of Compromise Associated with AvosLocker Ransomware. Retrieved January 11, 2023.
Open source URL - [4]mitre-attackS1053Open source URL
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