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MITRE ATT&CK® Malware

S0666: Gelsemium

Gelsemium is a modular malware comprised of a dropper (Gelsemine), a loader (Gelsenicine), and main (Gelsevirine) plug-ins written using the Microsoft Foundation Class (MFC) framework. Gelsemium has been used by the Gelsemium group since at least 2014.[1]

EnterpriseS0666MalwareObject v1.2Modified
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Glexia's Take · Automated analysis

Security context for executives and security teams

Automation confidenceMedium

S0666: Gelsemium describes [Gelsemium](https://attack.mitre.org/software/S0666) is a modular malware comprised of a dropper (Gelsemine), a loader (Gelsenicine), and main (Gelsevirine) plug-ins written using the Microsoft Foundation Class (MFC) framework. [Gelsemium](https://attack.mitre.org/software/S0666) has been used by the Gelsemium group since at least 2014.(Citation: ESET Gelsemium June 2021)

Executive priority

S0666: Gelsemium 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 S0666: Gelsemium 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 S0666: Gelsemium 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.

Official MITRE ATT&CK definition

Gelsemium

Gelsemium is a modular malware comprised of a dropper (Gelsemine), a loader (Gelsenicine), and main (Gelsevirine) plug-ins written using the Microsoft Foundation Class (MFC) framework. Gelsemium has been used by the Gelsemium group since at least 2014.[1]

View the same entry on attack.mitre.org (MITRE-hosted reference; in-page links above use the Glexia ATT&CK library.)

Glexia analysis

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.

ATT&CK relationship table

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.

33 rows
DomainIDNameRelationship / procedure
EnterpriseT1568Dynamic Resolution

Gelsemium can use dynamic DNS domain names in C2.[1]

EnterpriseT1140Deobfuscate/Decode Files or Information

Gelsemium can decompress and decrypt DLLs and shellcode.[1]

EnterpriseT1548.002Bypass User Account ControlSub-technique

Gelsemium can bypass UAC to elevate process privileges on a compromised host.[1]

EnterpriseT1095Non-Application Layer Protocol

Gelsemium has the ability to use TCP and UDP in C2 communications.[1]

EnterpriseT1543.003Windows ServiceSub-technique

Gelsemium can drop itself in `C:\Windows\System32\spool\prtprocs\x64\winprint.dll` as an alternative Print Processor to be loaded automatically when the spoolsv Windows service starts.[1]

EnterpriseT1070.004File DeletionSub-technique

Gelsemium can delete its dropper component from the targeted system.[1]

EnterpriseT1620Reflective Code Loading

Gelsemium can use custom shellcode to map embedded DLLs into memory.[1]

EnterpriseT1547.012Print ProcessorsSub-technique

Gelsemium can drop itself in C:\Windows\System32\spool\prtprocs\x64\winprint.dll to be loaded automatically by the spoolsv Windows service.[1]

EnterpriseT1547.001Registry Run Keys / Startup FolderSub-technique

Gelsemium can set persistence with a Registry run key.[1]

EnterpriseT1497Virtualization/Sandbox Evasion

Gelsemium can use junk code to generate random activity to obscure malware behavior.[1]

EnterpriseT1027.011Fileless StorageSub-technique

Gelsemium can store its components in the Registry.[1]

EnterpriseT1112Modify Registry

Gelsemium can modify the Registry to store its components.[1]

EnterpriseT1057Process Discovery

Gelsemium can enumerate running processes.[1]

EnterpriseT1071.004DNSSub-technique

Gelsemium has the ability to use DNS in communication with C2.[1]

EnterpriseT1083File and Directory Discovery

Gelsemium can retrieve data from specific Windows directories, as well as open random files as part of Virtualization/Sandbox Evasion.[1]

EnterpriseT1082System Information Discovery

Gelsemium can determine the operating system and whether a targeted machine has a 32 or 64 bit architecture.[1]

EnterpriseT1518.001Security Software DiscoverySub-technique

Gelsemium can check for the presence of specific security products.[1]

EnterpriseT1105Ingress Tool Transfer

Gelsemium can download additional plug-ins to a compromised host.[1]

EnterpriseT1033System Owner/User Discovery

Gelsemium has the ability to distinguish between a standard user and an administrator on a compromised host.[1]

EnterpriseT1008Fallback Channels

Gelsemium can use multiple domains and protocols in C2.[1]

EnterpriseT1005Data from Local System

Gelsemium can collect data from a compromised host.[1]

EnterpriseT1055.001Dynamic-link Library InjectionSub-technique

Gelsemium has the ability to inject DLLs into specific processes.[1]

EnterpriseT1134Access Token Manipulation

Gelsemium can use token manipulation to bypass UAC on Windows7 systems.[1]

EnterpriseT1070.006TimestompSub-technique

Gelsemium has the ability to perform timestomping of files on targeted systems.[1]

EnterpriseT1012Query Registry

Gelsemium can open random files and Registry keys to obscure malware behavior from sandbox analysis.[1]

EnterpriseT1106Native API

Gelsemium has the ability to use various Windows API functions to perform tasks.[1]

EnterpriseT1071.001Web ProtocolsSub-technique

Gelsemium can use HTTP/S in C2 communications.[1]

EnterpriseT1059.003Windows Command ShellSub-technique

Gelsemium can use a batch script to delete itself.[1]

EnterpriseT1036.001Invalid Code SignatureSub-technique

Gelsemium has used unverified signatures on malicious DLLs.[1]

EnterpriseT1027.016Junk Code InsertionSub-technique

Gelsemium can use junk code to hide functions and evade detection.[1]

EnterpriseT1027.015CompressionSub-technique

Gelsemium has the ability to compress its components.[1]

EnterpriseT1036.005Match Legitimate Resource Name or LocationSub-technique

Gelsemium has named malicious binaries `serv.exe`, `winprint.dll`, and `chrome_elf.dll` and has set its persistence in the Registry with the key value Chrome Update to appear legitimate.[1]

EnterpriseT1559.001Component Object ModelSub-technique

Gelsemium can use the `IARPUinstallerStringLauncher` COM interface are part of its UAC bypass process.[1]

Relationship explorer

All related ATT&CK context

uses · TechniqueT1568: Dynamic ResolutionEnterpriseuses · TechniqueT1140: Deobfuscate/Decode Files or InformationEnterpriseuses · TechniqueT1548.002: Bypass User Account ControlEnterpriseuses · TechniqueT1095: Non-Application Layer ProtocolEnterpriseuses · TechniqueT1543.003: Windows ServiceEnterpriseuses · TechniqueT1070.004: File DeletionEnterpriseuses · TechniqueT1620: Reflective Code LoadingEnterpriseuses · TechniqueT1547.012: Print ProcessorsEnterpriseuses · TechniqueT1547.001: Registry Run Keys / Startup FolderEnterpriseuses · TechniqueT1497: Virtualization/Sandbox EvasionEnterpriseuses · TechniqueT1027.011: Fileless StorageEnterpriseuses · TechniqueT1112: Modify RegistryEnterpriseuses · TechniqueT1057: Process DiscoveryEnterpriseuses · TechniqueT1071.004: DNSEnterpriseuses · TechniqueT1083: File and Directory DiscoveryEnterpriseuses · TechniqueT1082: System Information DiscoveryEnterpriseuses · TechniqueT1518.001: Security Software DiscoveryEnterpriseuses · TechniqueT1105: Ingress Tool TransferEnterpriseuses · TechniqueT1033: System Owner/User DiscoveryEnterpriseuses · TechniqueT1008: Fallback ChannelsEnterpriseuses · TechniqueT1005: Data from Local SystemEnterpriseuses · TechniqueT1055.001: Dynamic-link Library InjectionEnterpriseuses · TechniqueT1134: Access Token ManipulationEnterpriseuses · TechniqueT1070.006: TimestompEnterprise
Change history

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.

ATT&CK release
19.2
Object version
1.2
Created
Modified
Raw hash
1bcc5a4a4b2ed338...
Imported snapshots across ATT&CK releases(2)
ReleaseBundle importedObject versionModifiedStatusRaw hash
19.21.2Current bundle1bcc5a4a4b2e…
19.11.2Older bundle1bcc5a4a4b2e…
Raw source

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.

Open mirrored raw JSONOpen MITRE-hosted copy
Source references

External references and citations

MITRE external references are preserved separately from Glexia analysis so citations remain traceable to their original source records.

  1. [1]
    ESET Gelsemium June 2021

    Dupuy, T. and Faou, M. (2021, June). Gelsemium. Retrieved November 30, 2021.

    Open source URL
  2. [2]
    Gelsemine

    (Citation: ESET Gelsemium June 2021)

  3. [3]
    Gelsenicine

    (Citation: ESET Gelsemium June 2021)

  4. [4]
    Gelsevirine

    (Citation: ESET Gelsemium June 2021)

  5. [5]
    mitre-attackS0666
    Open source URL
Source and licensing

Source: MITRE ATT&CK®. © 2026 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. MITRE ATT&CK and ATT&CK are registered trademarks of The MITRE Corporation. Glexia is not affiliated with or endorsed by MITRE.

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