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MITRE ATT&CK® Malware

S0629: RainyDay

RainyDay is a backdoor tool that has been used by Naikon since at least 2020.[1]

EnterpriseS0629MalwareObject v1.1Modified
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Glexia's Take · Automated analysis

Security context for executives and security teams

Automation confidenceHigh

RainyDay is a Windows backdoor associated in ATT&CK with Naikon and reported as used since at least 2020. Its value to defenders is not in a single signature from the ATT&CK record—none is provided—but in the behavior chain ATT&CK relates to it: persistence through scheduled tasks or Windows services, discovery, command execution, credential access, collection, staging, command-and-control, tool transfer, and exfiltration to cloud storage. For leaders, this is a reminder that backdoor risk is usually decided by whether the organization can prove visibility across endpoints, credentials, outbound traffic, and data movement—not just whether malware alerts exist.

Executive priority

Treat RainyDay as a coverage-validation case for Windows endpoint resilience and espionage-style intrusion readiness. Priority questions include: Can the SOC see suspicious Windows service and scheduled task changes? Can incident responders reconstruct local discovery, credential access, data staging, and file deletion? Are browser and Windows Credential Manager protections and monitoring in scope? Can cloud storage exfiltration be distinguished from normal business use? Because ATT&CK provides no official detection text for this malware, risk owners should avoid assuming tool-specific coverage and instead require evidence that related behaviors are logged, alerted, and response-tested.

Technical view

ATT&CK lists RainyDay as Windows malware and relates it to techniques spanning execution, persistence, privilege escalation, discovery, credential access, collection, command-and-control, exfiltration, and stealth. SOC and IR teams should validate detection logic around Windows Command Shell activity, native API-driven behavior where telemetry allows, new or modified scheduled tasks and Windows services, service/task masquerading, suspicious file names or locations, process/service/file discovery, local data staging, screen capture, browser and Windows Credential Manager access, tool ingress, proxy or fallback C2 behavior, web-protocol and non-application-layer communications, file deletion, and encoded/encrypted artifacts followed by decoding activity. The Naikon relationship should be used for threat-intelligence context, not as proof of current local exposure.

Likely telemetry

  • Windows endpoint process creation and command-line telemetry
  • Windows service creation/modification events and related registry/service configuration data
  • Scheduled task creation, modification, and execution telemetry
  • File system events for staging directories, suspicious file placement, encoded/encrypted artifacts, and file deletion
  • Endpoint security/EDR observations for native API use, screen capture behavior, tool transfer, and credential store access

Detection direction

  • Build coverage around the related ATT&CK behaviors rather than a malware name alone, since official ATT&CK detection guidance is not provided for RainyDay.
  • Correlate persistence indicators—new scheduled tasks, new or modified Windows services, and masqueraded task/service names—with unusual parent processes, command shell use, or recently written binaries.
  • Tune discovery detections for clusters of process, service, file, and directory enumeration, especially when followed by staging, credential access, tool transfer, or outbound network activity.
  • Validate monitoring for access to browser credential stores and Windows Credential Manager, with care for administrative tools and legitimate credential-management workflows that may generate false positives.
  • Review outbound network analytics for unusual web-protocol communications, proxy behavior, fallback destinations, or non-application-layer protocol usage, while accounting for normal enterprise web and cloud traffic.

Mitigation priorities

  • Prioritize Windows endpoint logging and EDR coverage for process creation, command lines, services, scheduled tasks, file writes/deletions, and credential-store access.
  • Harden and monitor persistence surfaces: restrict who can create services and scheduled tasks, review privileged group membership, and baseline legitimate task/service names and paths.
  • Reduce credential exposure by limiting saved browser credentials where feasible, strengthening Windows credential protections, and enforcing least privilege for accounts used on endpoints.
  • Control and monitor outbound communications, including proxy use, unusual protocols, and cloud storage access, with business-approved destinations and investigation workflows for exceptions.
  • Prepare IR playbooks that collect persistence inventories, process trees, credential-access evidence, staged files, deleted-file indicators, and cloud transfer records from affected Windows systems.
Additional notes and limits

The ATT&CK object identifies RainyDay as a Windows backdoor used by Naikon since at least 2020 and provides one external Bitdefender reference. The object itself has no ATT&CK tactics listed and no official detection text; the practical defensive view above is derived from the supplied relationship context showing the techniques RainyDay uses. Several related techniques list non-Windows platforms in their general ATT&CK descriptions, but RainyDay’s supplied platform is Windows, so Windows should be treated as the supported scope for this object.

This take is limited to the supplied STIX fields, external references, and relationships. It does not include indicators of compromise, hashes, infrastructure, exploit details, prevalence, current activity, or guaranteed detection logic. Organizations need local endpoint, identity, network, and cloud telemetry to determine exposure or coverage.

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Official MITRE ATT&CK definition

RainyDay

RainyDay is a backdoor tool that has been used by Naikon since at least 2020.[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.

25 rows
DomainIDNameRelationship / procedure
EnterpriseT1036.005Match Legitimate Resource Name or LocationSub-technique

RainyDay has used names to mimic legitimate software including "vmtoolsd.exe" to spoof Vmtools.[1]

EnterpriseT1106Native API

The file collection tool used by RainyDay can utilize native API including ReadDirectoryChangeW for folder monitoring.[1]

EnterpriseT1070.004File DeletionSub-technique

RainyDay has the ability to uninstall itself by deleting its service and files.[1]

EnterpriseT1567.002Exfiltration to Cloud StorageSub-technique

RainyDay can use a file exfiltration tool to upload specific files to Dropbox.[1]

EnterpriseT1105Ingress Tool Transfer

RainyDay can download files to a compromised host.[1]

EnterpriseT1140Deobfuscate/Decode Files or Information

RainyDay can decrypt its payload via a XOR key.[1]

EnterpriseT1071.001Web ProtocolsSub-technique

RainyDay can use HTTP in C2 communications.[1]

EnterpriseT1036.004Masquerade Task or ServiceSub-technique

RainyDay has named services and scheduled tasks to appear benign including "ChromeCheck" and "googleupdate."[1]

EnterpriseT1007System Service Discovery

RainyDay can create and register a service for execution.[1]

EnterpriseT1057Process Discovery

RainyDay can enumerate processes on a target system.[1]

EnterpriseT1074.001Local Data StagingSub-technique

RainyDay can use a file exfiltration tool to copy files to C:\ProgramData\Adobe\temp prior to exfiltration.[1]

EnterpriseT1555.003Credentials from Web BrowsersSub-technique

RainyDay can use tools to collect credentials from web browsers.[1]

EnterpriseT1027.013Encrypted/Encoded FileSub-technique

RainyDay has downloaded as a XOR-encrypted payload.[1]

EnterpriseT1008Fallback Channels

RainyDay has the ability to switch between TCP and HTTP for C2 if one method is not working.[1]

EnterpriseT1543.003Windows ServiceSub-technique

RainyDay can use services to establish persistence.[1]

EnterpriseT1059.003Windows Command ShellSub-technique

RainyDay can use the Windows Command Shell for execution.[1]

EnterpriseT1090Proxy

RainyDay can use proxy tools including boost_proxy_client for reverse proxy functionality.[1]

EnterpriseT1113Screen Capture

RainyDay has the ability to capture screenshots.[1]

EnterpriseT1083File and Directory Discovery

RainyDay can use a file exfiltration tool to collect recently changed files with specific extensions.[1]

EnterpriseT1555.004Windows Credential ManagerSub-technique

RainyDay can use the QuarksPwDump tool to obtain local passwords and domain cached credentials.[1]

EnterpriseT1053.005Scheduled TaskSub-technique

RainyDay can use scheduled tasks to achieve persistence.[1]

EnterpriseT1095Non-Application Layer Protocol

RainyDay can use TCP in C2 communications.[1]

EnterpriseT1573.001Symmetric CryptographySub-technique

RainyDay can use RC4 to encrypt C2 communications.[1]

EnterpriseT1574.001DLLSub-technique

RainyDay can use side-loading to run malicious executables.[1]

EnterpriseT1005Data from Local System

RainyDay can use a file exfiltration tool to collect recently changed files on a compromised host.[1]

Associated objects

Groups, software, and campaigns

GroupEnterprise

G0019: Naikon

Naikon is assessed to be a state-sponsored cyber espionage group attributed to the Chinese People’s Liberation Army’s (PLA) Chengdu Military Region Second Technical Reconnaissance Bureau (Military Unit Cover Designator 78020).[1] Active since at least 2010, Naikon has primarily conducted operations against government, military, and civil organizations in Southeast Asia, as well as against international bodies such as the United Nations Development Programme (UNDP) and the Association of Southeast Asian Nations (ASEAN).[1][2]

While Naikon shares some characteristics with APT30, the two groups do not appear to be exact matches.[3]

Relationship explorer

All related ATT&CK context

uses · TechniqueT1036.005: Match Legitimate Resource Name or LocationEnterpriseuses · TechniqueT1106: Native APIEnterpriseuses · TechniqueT1070.004: File DeletionEnterpriseuses · TechniqueT1567.002: Exfiltration to Cloud StorageEnterpriseuses · TechniqueT1105: Ingress Tool TransferEnterpriseuses · TechniqueT1140: Deobfuscate/Decode Files or InformationEnterpriseuses · TechniqueT1071.001: Web ProtocolsEnterpriseuses · TechniqueT1036.004: Masquerade Task or ServiceEnterpriseuses · TechniqueT1007: System Service DiscoveryEnterpriseuses · TechniqueT1057: Process DiscoveryEnterpriseuses · TechniqueT1074.001: Local Data StagingEnterpriseuses · GroupG0019: NaikonEnterpriseuses · TechniqueT1555.003: Credentials from Web BrowsersEnterpriseuses · TechniqueT1027.013: Encrypted/Encoded FileEnterpriseuses · TechniqueT1008: Fallback ChannelsEnterpriseuses · TechniqueT1543.003: Windows ServiceEnterpriseuses · TechniqueT1059.003: Windows Command ShellEnterpriseuses · TechniqueT1090: ProxyEnterpriseuses · TechniqueT1113: Screen CaptureEnterpriseuses · TechniqueT1083: File and Directory DiscoveryEnterpriseuses · TechniqueT1555.004: Windows Credential ManagerEnterpriseuses · TechniqueT1053.005: Scheduled TaskEnterpriseuses · TechniqueT1095: Non-Application Layer ProtocolEnterpriseuses · 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
19.1
Object version
1.1
Created
Modified
Raw hash
008c324ce07b0c52...
Imported snapshots across ATT&CK releases(1)
ReleaseBundle importedObject versionModifiedStatusRaw hash
19.11.1Current bundle008c324ce07b…
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]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  4. [4]
    mitre-attackS0629
    Open source URL
  5. [5]
    mitre-attackS0629
    Open source URL
  6. [6]
    mitre-attackS0629
    Open source URL
  7. [7]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  8. [8]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  9. [9]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  10. [10]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  13. [13]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  17. [17]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  18. [18]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  21. [21]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  22. [22]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  24. [24]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  25. [25]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  30. [30]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  31. [31]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  32. [32]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
  33. [33]
    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

    Vrabie, V. (2021, April 23). NAIKON – Traces from a Military Cyber-Espionage Operation. Retrieved June 29, 2021.

    Open source URL
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    Bitdefender Naikon April 2021

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    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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