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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 confidenceMedium

S0629: RainyDay describes [RainyDay](https://attack.mitre.org/software/S0629) is a backdoor tool that has been used by [Naikon](https://attack.mitre.org/groups/G0019) since at least 2020.(Citation: Bitdefender Naikon April 2021)

Executive priority

S0629: RainyDay 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 S0629: RainyDay 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 S0629: RainyDay 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

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 · GroupG0019: NaikonEnterpriseuses · 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 · 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
19.2
Object version
1.1
Created
Modified
Raw hash
008c324ce07b0c52...
Imported snapshots across ATT&CK releases(2)
ReleaseBundle importedObject versionModifiedStatusRaw hash
19.21.1Current bundle008c324ce07b…
19.11.1Older 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
  2. [2]
    mitre-attackS0629
    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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