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MITRE ATT&CK® Malware

S0663: SysUpdate

SysUpdate is a backdoor written in C++ that has been used by Threat Group-3390 since at least 2020.[1]

EnterpriseS0663MalwareObject v1.3Modified
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Glexia's Take · Automated analysis

Security context for executives and security teams

Automation confidenceMedium

S0663: SysUpdate describes [SysUpdate](https://attack.mitre.org/software/S0663) is a backdoor written in C++ that has been used by [Threat Group-3390](https://attack.mitre.org/groups/G0027) since at least 2020.(Citation: Trend Micro Iron Tiger April 2021)

Executive priority

S0663: SysUpdate 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 S0663: SysUpdate by reviewing the official ATT&CK relationships, mapped tactics (the mapped ATT&CK tactic context), supported platforms (Windows, Linux), 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 S0663: SysUpdate 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

SysUpdate

SysUpdate is a backdoor written in C++ that has been used by Threat Group-3390 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.

31 rows
DomainIDNameRelationship / procedure
EnterpriseT1071.004DNSSub-technique

SysUpdate has used DNS TXT requests as for its C2 communication.CitationLunghi Iron Tiger Linux

EnterpriseT1573.001Symmetric CryptographySub-technique

SysUpdate has used DES to encrypt all C2 communications.CitationLunghi Iron Tiger Linux

EnterpriseT1007System Service Discovery

SysUpdate can collect a list of services on a victim machine.CitationLunghi Iron Tiger Linux

EnterpriseT1140Deobfuscate/Decode Files or Information

SysUpdate can deobfuscate packed binaries in memory.[1]

EnterpriseT1680Local Storage Discovery

SysUpdate can collect a system's drive information.[1]CitationLunghi Iron Tiger Linux

EnterpriseT1132.001Standard EncodingSub-technique

SysUpdate has used Base64 to encode its C2 traffic.CitationLunghi Iron Tiger Linux

EnterpriseT1033System Owner/User Discovery

SysUpdate can collect the username from a compromised host.CitationLunghi Iron Tiger Linux

EnterpriseT1057Process Discovery

SysUpdate can collect information about running processes.CitationLunghi Iron Tiger Linux

EnterpriseT1553.002Code SigningSub-technique

SysUpdate has been signed with stolen digital certificates.CitationLunghi Iron Tiger Linux

EnterpriseT1005Data from Local System

SysUpdate can collect information and files from a compromised host.CitationLunghi Iron Tiger Linux

EnterpriseT1027.011Fileless StorageSub-technique

SysUpdate can store its encoded configuration file within Software\Classes\scConfig in either HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER.[1]

EnterpriseT1083File and Directory Discovery

SysUpdate can search files on a compromised host.[1]CitationLunghi Iron Tiger Linux

EnterpriseT1016.001Internet Connection DiscoverySub-technique

SysUpdate can contact the DNS server operated by Google as part of its C2 establishment process.CitationLunghi Iron Tiger Linux

EnterpriseT1105Ingress Tool Transfer

SysUpdate has the ability to download files to a compromised host.[1]CitationLunghi Iron Tiger Linux

EnterpriseT1036.004Masquerade Task or ServiceSub-technique

SysUpdate has named their unit configuration file similarly to other unit files residing in the same directory, `/usr/lib/systemd/system/`, to appear benign.CitationLunghi Iron Tiger Linux

EnterpriseT1041Exfiltration Over C2 Channel

SysUpdate has exfiltrated data over its C2 channel.CitationLunghi Iron Tiger Linux

EnterpriseT1027.013Encrypted/Encoded FileSub-technique

SysUpdate can encrypt and encode its configuration file.[1]

EnterpriseT1082System Information Discovery

SysUpdate can collect a system's architecture, operating system version, and hostname.[1]CitationLunghi Iron Tiger Linux

EnterpriseT1113Screen Capture

SysUpdate has the ability to capture screenshots.[1]

EnterpriseT1543.002Systemd ServiceSub-technique

SysUpdate can copy a script to the user owned `/usr/lib/systemd/system/` directory with a symlink mapped to a `root` owned directory, `/etc/ystem/system`, in the unit configuration file's `ExecStart` directive to establish persistence and elevate privileges.CitationLunghi Iron Tiger Linux

EnterpriseT1070.004File DeletionSub-technique

SysUpdate can delete its configuration file from the targeted system.[1]

EnterpriseT1112Modify Registry

SysUpdate can write its configuration file to Software\Classes\scConfig in either HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER.[1]

EnterpriseT1564.001Hidden Files and DirectoriesSub-technique

SysUpdate has the ability to set file attributes to hidden.[1]

EnterpriseT1574.001DLLSub-technique

SysUpdate can load DLLs through vulnerable legitimate executables.[1]

EnterpriseT1547.001Registry Run Keys / Startup FolderSub-technique

SysUpdate can use a Registry Run key to establish persistence.[1]

EnterpriseT1016System Network Configuration Discovery

SysUpdate can collected the IP address and domain name of a compromised host.CitationLunghi Iron Tiger Linux

EnterpriseT1027.002Software PackingSub-technique

SysUpdate has been packed with VMProtect.[1]CitationLunghi Iron Tiger Linux

EnterpriseT1106Native API

SysUpdate can call the `GetNetworkParams` API as part of its C2 establishment process.CitationLunghi Iron Tiger Linux

EnterpriseT1569.002Service ExecutionSub-technique

SysUpdate can manage services and processes.[1]

EnterpriseT1047Windows Management Instrumentation

SysUpdate can use WMI for execution on a compromised host.[1]

EnterpriseT1543.003Windows ServiceSub-technique

SysUpdate can create a service to establish persistence.[1]

Associated objects

Groups, software, and campaigns

GroupEnterprise

G0027: Threat Group-3390

Threat Group-3390 is a Chinese threat group that has extensively used strategic Web compromises to target victims.[1] The group has been active since at least 2010 and has targeted organizations in the aerospace, government, defense, technology, energy, manufacturing and gambling/betting sectors.[2][3][4]

Relationship explorer

All related ATT&CK context

uses · TechniqueT1071.004: DNSEnterpriseuses · TechniqueT1573.001: Symmetric CryptographyEnterpriseuses · TechniqueT1007: System Service DiscoveryEnterpriseuses · TechniqueT1140: Deobfuscate/Decode Files or InformationEnterpriseuses · TechniqueT1680: Local Storage DiscoveryEnterpriseuses · TechniqueT1132.001: Standard EncodingEnterpriseuses · TechniqueT1033: System Owner/User DiscoveryEnterpriseuses · TechniqueT1057: Process DiscoveryEnterpriseuses · TechniqueT1553.002: Code SigningEnterpriseuses · TechniqueT1005: Data from Local SystemEnterpriseuses · TechniqueT1027.011: Fileless StorageEnterpriseuses · TechniqueT1083: File and Directory DiscoveryEnterpriseuses · TechniqueT1016.001: Internet Connection DiscoveryEnterpriseuses · TechniqueT1105: Ingress Tool TransferEnterpriseuses · TechniqueT1036.004: Masquerade Task or ServiceEnterpriseuses · TechniqueT1041: Exfiltration Over C2 ChannelEnterpriseuses · TechniqueT1027.013: Encrypted/Encoded FileEnterpriseuses · TechniqueT1082: System Information DiscoveryEnterpriseuses · TechniqueT1113: Screen CaptureEnterpriseuses · TechniqueT1543.002: Systemd ServiceEnterpriseuses · TechniqueT1070.004: File DeletionEnterpriseuses · TechniqueT1112: Modify RegistryEnterpriseuses · TechniqueT1564.001: Hidden Files and DirectoriesEnterpriseuses · TechniqueT1574.001: DLLEnterprise
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
20.0
Object version
1.3
Created
Modified
Raw hash
c6a12330e34c9b14...
Imported snapshots across ATT&CK releases(3)
ReleaseBundle importedObject versionModifiedStatusRaw hash
20.01.3Current bundlec6a12330e34c…
19.21.3Older bundlec6a12330e34c…
19.11.3Older bundlec6a12330e34c…
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]
    Trend Micro Iron Tiger April 2021

    Lunghi, D. and Lu, K. (2021, April 9). Iron Tiger APT Updates Toolkit With Evolved SysUpdate Malware. Retrieved November 12, 2021.

    Open source URL
  2. [2]
    FOCUSFJORD

    (Citation: Trend Micro Iron Tiger April 2021)

  3. [3]
    HyperSSL

    (Citation: Trend Micro Iron Tiger April 2021)

  4. [4]
    Soldier

    (Citation: Trend Micro Iron Tiger April 2021)

  5. [5]
    mitre-attackS0663
    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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