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MITRE ATT&CK® Malware

S0137: CORESHELL

CORESHELL is a downloader used by APT28. The older versions of this malware are known as SOURFACE and newer versions as CORESHELL.[1] [2]

EnterpriseS0137MalwareObject v2.2Modified
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Glexia's Take · Automated analysis

Security context for executives and security teams

Automation confidenceMedium

S0137: CORESHELL describes [CORESHELL](https://attack.mitre.org/software/S0137) is a downloader used by [APT28](https://attack.mitre.org/groups/G0007). The older versions of this malware are known as SOURFACE and newer versions as CORESHELL.(Citation: FireEye APT28) (Citation: FireEye APT28 January 2017)

Executive priority

S0137: CORESHELL 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 S0137: CORESHELL 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 S0137: CORESHELL 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

CORESHELL

CORESHELL is a downloader used by APT28. The older versions of this malware are known as SOURFACE and newer versions as CORESHELL.[1] [2]

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.

11 rows
DomainIDNameRelationship / procedure
EnterpriseT1071.001Web ProtocolsSub-technique

CORESHELL can communicate over HTTP for C2.[1]CitationMicrosoft SIR Vol 19

EnterpriseT1071.003Mail ProtocolsSub-technique

CORESHELL can communicate over SMTP and POP3 for C2.[1]CitationMicrosoft SIR Vol 19

EnterpriseT1132.001Standard EncodingSub-technique

CORESHELL C2 messages are Base64-encoded.[1]

EnterpriseT1680Local Storage Discovery

CORESHELL collects the volume serial number from the victim and sends the information to its C2 server.[1]

EnterpriseT1082System Information Discovery

CORESHELL collects hostname and OS version data from the victim and sends the information to its C2 server.[1]

EnterpriseT1027.016Junk Code InsertionSub-technique

CORESHELL contains unused machine instructions in a likely attempt to hinder analysis.[1]

EnterpriseT1218.011Rundll32Sub-technique

CORESHELL is installed via execution of rundll32 with an export named "init" or "InitW."CitationMicrosoft SIR Vol 19

EnterpriseT1547.001Registry Run Keys / Startup FolderSub-technique

CORESHELL has established persistence by creating autostart extensibility point (ASEP) Registry entries in the Run key and other Registry keys, as well as by creating shortcuts in the Internet Explorer Quick Start folder.CitationMicrosoft SIR Vol 19

EnterpriseT1105Ingress Tool Transfer

CORESHELL downloads another dropper from its C2 server.[1]

EnterpriseT1027Obfuscated Files or Information

CORESHELL obfuscates strings using a custom stream cipher.[1]

EnterpriseT1573.001Symmetric CryptographySub-technique

CORESHELL C2 messages are encrypted with custom stream ciphers using six-byte or eight-byte keys.[1]

Associated objects

Groups, software, and campaigns

GroupEnterprise

G0007: APT28

APT28 is a threat group that has been attributed to Russia's General Staff Main Intelligence Directorate (GRU) 85th Main Special Service Center (GTsSS) military unit 26165.[1][2] This group has been active since at least 2004.[3][4][5][6][7][8][9][10][11][12][13]

APT28 reportedly compromised the Hillary Clinton campaign, the Democratic National Committee, and the Democratic Congressional Campaign Committee in 2016 in an attempt to interfere with the U.S. presidential election.[5] In 2018, the US indicted five GRU Unit 26165 officers associated with APT28 for cyber operations (including close-access operations) conducted between 2014 and 2018 against the World Anti-Doping Agency (WADA), the US Anti-Doping Agency, a US nuclear facility, the Organization for the Prohibition of Chemical Weapons (OPCW), the Spiez Swiss Chemicals Laboratory, and other organizations.[14] Some of these were conducted with the assistance of GRU Unit 74455, which is also referred to as Sandworm Team.

Relationship explorer

All related ATT&CK context

uses · GroupG0007: APT28Enterpriseuses · TechniqueT1071.001: Web ProtocolsEnterpriseuses · TechniqueT1071.003: Mail ProtocolsEnterpriseuses · TechniqueT1132.001: Standard EncodingEnterpriseuses · TechniqueT1680: Local Storage DiscoveryEnterpriseuses · TechniqueT1082: System Information DiscoveryEnterpriseuses · TechniqueT1027.016: Junk Code InsertionEnterpriseuses · TechniqueT1218.011: Rundll32Enterpriseuses · TechniqueT1547.001: Registry Run Keys / Startup FolderEnterpriseuses · TechniqueT1105: Ingress Tool TransferEnterpriseuses · TechniqueT1027: Obfuscated Files or InformationEnterpriseuses · TechniqueT1573.001: Symmetric CryptographyEnterprise
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
2.2
Created
Modified
Raw hash
7cfda86561175e3c...
Imported snapshots across ATT&CK releases(2)
ReleaseBundle importedObject versionModifiedStatusRaw hash
19.22.2Current bundle7cfda8656117…
19.12.2Older bundle7cfda8656117…
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]
    FireEye APT28

    FireEye. (2015). APT28: A WINDOW INTO RUSSIA’S CYBER ESPIONAGE OPERATIONS?. Retrieved August 19, 2015.

    Open source URL
  2. [2]
    FireEye APT28 January 2017

    FireEye iSIGHT Intelligence. (2017, January 11). APT28: At the Center of the Storm. Retrieved November 17, 2024.

    Open source URL
  3. [3]
    CORESHELL

    (Citation: FireEye APT28) (Citation: FireEye APT28 January 2017)

  4. [4]
    SOURFACE

    (Citation: FireEye APT28) (Citation: FireEye APT28 January 2017)(Citation: Securelist Sofacy Feb 2018)

  5. [5]
    Securelist Sofacy Feb 2018

    Kaspersky Lab's Global Research & Analysis Team. (2018, February 20). A Slice of 2017 Sofacy Activity. Retrieved November 27, 2018.

    Open source URL
  6. [6]
    Sofacy

    This designation has been used in reporting both to refer to the threat group ([APT28](https://attack.mitre.org/groups/G0007)) and its associated malware.(Citation: FireEye APT28) (Citation: FireEye APT28 January 2017)(Citation: Securelist Sofacy Feb 2018)

  7. [7]
    mitre-attackS0137
    Open source URL
Source and licensing

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