Open Asset Model¶

The Amass Project's Open Asset Model redefines the understanding of an attack surface. Shifting the paradigm away from narrow, internet infrastructure-focused collection, the OAM broadens its scope to include both physical and digital assets. This approach delivers a realistic view of assets and their lesser-known associations, utilizing adversarial tactics to gain visibility into potential risks and attack vectors that might otherwise be overlooked.

// Overview¶

• Deep Attack Surface Intelligence: Identifies both physical and digital assets, moving beyond IT infrastructure.
• Standardized Asset Framework: Ensures consistency in asset classification, facilitating efficient data exchange and streamlined analysis.
• Cyclic Discovery: Recursively approaches data exploration, leveraging each finding to dynamically expand the target scope.
• Community-Driven: Developed and continuously refined by security experts within the OWASP Amass ecosystem.
• Risk Mapping: Exposes hidden attack vectors by mapping asset relationships and tracking their changes over time.

Explore OAM Asset Types¶

Technical Reference¶

This section provides architectural diagrams and schema details drawn from the OAM Go package internals.

Package Structure¶

OAM is organized into domain-specific Go packages, each containing related asset types:

graph TB
    subgraph "open-asset-model"
        Base["oam (base package)<br/>AssetType interface<br/>Relation interface"]

        General["general<br/>• Identifier<br/>• SourceProperty<br/>• SimpleRelation<br/>• PortRelation<br/>• Location"]

        DNS["dns<br/>• FQDN"]

        Network["network<br/>• IPAddress<br/>• Netblock<br/>• AutonomousSystem"]

        Org["org<br/>• Organization"]

        Registration["registration<br/>• DomainRecord<br/>• AutnumRecord<br/>• IPNetRecord"]

        Certificate["certificate<br/>• TLSCertificate"]

        Contact["contact<br/>• ContactRecord<br/>• Phone"]

        People["people<br/>• Person"]

        Platform["platform<br/>• Service"]

        Financial["financial<br/>• FundsTransfer"]

        Account["account<br/>• Account"]

        URL["url<br/>• URL"]
    end

    subgraph "Amass Integration"
        DBTypes["asset-db/types<br/>dbt.Entity<br/>dbt.Edge"]
        EngineTypes["engine/types<br/>et.Event<br/>et.Asset"]
    end

    Base --> General
    Base --> DNS
    Base --> Network
    Base --> Org
    Base --> Registration
    Base --> Certificate
    Base --> Contact
    Base --> People
    Base --> Platform
    Base --> Financial
    Base --> Account
    Base --> URL

    General --> DBTypes
    DNS --> DBTypes
    Network --> DBTypes
    Org --> DBTypes

    DBTypes --> EngineTypes

Asset Instantiation Pattern¶

All OAM assets follow a consistent lifecycle from creation to event dispatch:

graph LR
    A["Create OAM Asset<br/>oamdns.FQDN"] --> B["Wrap in dbt.Entity<br/>session.Cache().CreateAsset()"]
    B --> C["Add Source Property<br/>general.SourceProperty"]
    C --> D["Create Edge<br/>session.Cache().CreateEdge()"]
    D --> E["Add Edge Property<br/>general.SourceProperty"]
    E --> F["Dispatch Event<br/>et.Event with Entity"]

Asset-to-Entity Wrapping¶

OAM assets are wrapped in dbt.Entity structures for storage and event propagation:

graph TB
    subgraph "OAM Layer"
        OAM["OAM Asset<br/>e.g., oamdns.FQDN<br/>implements AssetType()"]
    end

    subgraph "Database Layer"
        Entity["dbt.Entity<br/>• ID: string<br/>• Asset: oam.Asset<br/>• CreatedAt: time.Time<br/>• LastSeen: time.Time"]

        Properties["dbt.Property<br/>• general.SourceProperty<br/>• Custom properties"]

        Edge["dbt.Edge<br/>• Relation: oam.Relation<br/>• FromEntity: dbt.Entity<br/>• ToEntity: dbt.Entity"]
    end

    subgraph "Event Layer"
        Event["et.Event<br/>• Name: string<br/>• Entity: dbt.Entity<br/>• Session: et.Session<br/>• Meta: interface{}"]
    end

    OAM --> Entity
    Entity --> Properties
    Entity --> Edge
    Entity --> Event

Data Flow: Discovery to Storage¶

graph TB
    subgraph "Discovery Phase"
        Plugin["Plugin<br/>(e.g., DNS-IP)"]
        Discovery["Discover Data<br/>(DNS query result)"]
    end

    subgraph "Asset Creation Phase"
        CreateOAM["Create OAM Asset<br/>oamnet.IPAddress<br/>{Address: 192.0.2.1}"]
        WrapEntity["Wrap in dbt.Entity<br/>session.Cache().CreateAsset()"]
        AddSource["Add SourceProperty<br/>{Source: 'DNS-IP', Confidence: 100}"]
    end

    subgraph "Relationship Phase"
        CreateEdge["Create Edge<br/>FQDN --dns_record--> IPAddress"]
        AddEdgeSource["Add Edge SourceProperty"]
    end

    subgraph "Graph Storage"
        Cache["Session Cache<br/>(In-Memory)"]
        GraphDB["Graph Database<br/>(Asset-DB)"]
    end

    subgraph "Event Dispatch"
        DispatchEvent["Dispatch et.Event<br/>{Entity: ipEntity}"]
        OtherPlugins["Other Plugins<br/>(e.g., IP-Reverse)"]
    end

    Plugin --> Discovery
    Discovery --> CreateOAM
    CreateOAM --> WrapEntity
    WrapEntity --> AddSource
    AddSource --> CreateEdge
    CreateEdge --> AddEdgeSource
    AddEdgeSource --> Cache
    Cache --> GraphDB
    AddEdgeSource --> DispatchEvent
    DispatchEvent --> OtherPlugins

Process steps:

1. Discovery: Plugin queries external source (DNS, API, etc.)
2. Asset Creation: Raw data converted to typed OAM asset
3. Entity Wrapping: Asset stored in cache, returns dbt.Entity
4. Attribution: SourceProperty added to entity
5. Relationship Creation: Edge created between related entities
6. Edge Attribution: SourceProperty added to edge
7. Storage: Entity and edge persisted to graph database
8. Event Dispatch: New entity wrapped in et.Event for further processing

Scope Conversion to Assets¶

User-provided scope (domains, IPs, CIDRs, ASNs) is converted to OAM assets during enumeration initialization:

graph LR
    subgraph "Configuration Scope"
        Domains["config.Scope.Domains<br/>[]string"]
        IPs["config.Scope.Addresses<br/>[]net.IP"]
        CIDRs["config.Scope.CIDRs<br/>[]*net.IPNet"]
        ASNs["config.Scope.ASNs<br/>[]int"]
    end

    subgraph "OAM Assets"
        FQDNAsset["oamdns.FQDN"]
        IPAsset["oamnet.IPAddress"]
        NetblockAsset["oamnet.Netblock"]
        ASAsset["oamnet.AutonomousSystem"]
    end

    subgraph "Engine Assets"
        EngineAsset["et.Asset<br/>{Name, Data: AssetData}"]
    end

    Domains --> FQDNAsset
    IPs --> IPAsset
    CIDRs --> NetblockAsset
    ASNs --> ASAsset

    FQDNAsset --> EngineAsset
    IPAsset --> EngineAsset
    NetblockAsset --> EngineAsset
    ASAsset --> EngineAsset

Common Relation Types¶

Asset Type Constants¶

All asset types are referenced as typed constants in the oam base package:

const (
    FQDN             AssetType = "fqdn"
    IPAddress        AssetType = "ip_address"
    Netblock         AssetType = "netblock"
    AutonomousSystem AssetType = "autonomous_system"
    Organization     AssetType = "organization"
    Identifier       AssetType = "identifier"
    DomainRecord     AssetType = "domain_record"
    AutnumRecord     AssetType = "autnum_record"
    IPNetRecord      AssetType = "ipnet_record"
    TLSCertificate   AssetType = "tls_certificate"
    ContactRecord    AssetType = "contact_record"
    Person           AssetType = "person"
    Service          AssetType = "service"
    Location         AssetType = "location"
    Phone            AssetType = "phone"
    URL              AssetType = "url"
    Account          AssetType = "account"
)

These constants are used in handler registration, transformation configuration, and TTL management per asset type.

OAM Specification Architecture¶

Core Interface Specifications¶

graph LR
    Asset["Asset Interface"]
    Relation["Relation Interface"]
    Property["Property Interface"]

    Asset -->|"Key() string"| KeyMethod["Unique identifier"]
    Asset -->|"AssetType() AssetType"| TypeMethod["Type constant"]
    Asset -->|"JSON() ([]byte, error)"| JSONMethod["Serialization"]

    Relation -->|"Label() string"| LabelMethod["Relationship name"]
    Relation -->|"RelationType() RelationType"| RTypeMethod["Relation category"]
    Relation -->|"JSON() ([]byte, error)"| RJSONMethod["Serialization"]

    Property -->|"Name() string"| NameMethod["Property name"]
    Property -->|"Value() string"| ValueMethod["Property value"]
    Property -->|"PropertyType() PropertyType"| PTypeMethod["Property category"]
    Property -->|"JSON() ([]byte, error)"| PJSONMethod["Serialization"]

Three-Tier Architecture Overview¶

graph TB
    subgraph Layer1["Core Abstraction Layer (Interfaces)"]
        Asset["Asset Interface<br/>Key() string<br/>AssetType() AssetType<br/>JSON() ([]byte, error)"]
        Relation["Relation Interface<br/>Label() string<br/>RelationType() RelationType<br/>JSON() ([]byte, error)"]
        Property["Property Interface<br/>Name() string<br/>Value() string<br/>PropertyType() PropertyType<br/>JSON() ([]byte, error)"]
    end

    subgraph Layer2["Type System Layer (Enumerations)"]
        AssetType["AssetType<br/>21 constants<br/>Account, FQDN, IPAddress, etc."]
        RelationType["RelationType<br/>5 constants<br/>BasicDNSRelation, PortRelation, etc."]
        PropertyType["PropertyType<br/>4 constants<br/>DNSRecordProperty, SimpleProperty, etc."]
    end

    subgraph Layer3["Concrete Implementation Layer"]
        FileStruct["file.File struct<br/>implements Asset"]
        FQDNStruct["network.FQDN struct<br/>implements Asset"]
        BasicDNS["dns.BasicDNSRelation struct<br/>implements Relation"]
        SimpleRel["general.SimpleRelation struct<br/>implements Relation"]
        SourceProp["property.SourceProperty struct<br/>implements Property"]
    end

    Asset -.->|"returns"| AssetType
    Relation -.->|"returns"| RelationType
    Property -.->|"returns"| PropertyType

    FileStruct -.->|"implements"| Asset
    FQDNStruct -.->|"implements"| Asset
    BasicDNS -.->|"implements"| Relation
    SimpleRel -.->|"implements"| Relation
    SourceProp -.->|"implements"| Property

    FileStruct -.->|"returns model.File"| AssetType
    BasicDNS -.->|"returns BasicDNSRelation"| RelationType

Asset Type Taxonomy¶

graph TD
    Root["AssetType Enumeration"]

    Root --> Network["Network Infrastructure<br/>(6 types)"]
    Root --> Org["Organizational<br/>(5 types)"]
    Root --> Digital["Digital Artifacts<br/>(5 types)"]
    Root --> Financial["Financial<br/>(2 types)"]
    Root --> Product["Product<br/>(2 types)"]
    Root --> Registration["Registration<br/>(3 types)"]
    Root --> Identity["Identity<br/>(1 type)"]

    Network --> FQDN["FQDN"]
    Network --> IPAddress["IPAddress"]
    Network --> Netblock["Netblock"]
    Network --> AutonomousSystem["AutonomousSystem"]

    Org --> Organization["Organization"]
    Org --> Person["Person"]
    Org --> Location["Location"]
    Org --> Phone["Phone"]
    Org --> ContactRecord["ContactRecord"]

    Digital --> File["File"]
    Digital --> URL["URL"]
    Digital --> Service["Service"]
    Digital --> TLSCertificate["TLSCertificate"]
    Digital --> DomainRecord["DomainRecord"]

    Financial --> Account["Account"]
    Financial --> FundsTransfer["FundsTransfer"]

    Product --> ProductType["Product"]
    Product --> ProductRelease["ProductRelease"]

    Registration --> DomainRec["DomainRecord"]
    Registration --> AutnumRecord["AutnumRecord"]
    Registration --> IPNetRecord["IPNetRecord"]

    Identity --> Identifier["Identifier"]

Relationship Validation System¶

graph TB
    Discover["Discovery Tool<br/>(e.g., OWASP Amass)"]
    ValidRel["ValidRelationship()"]
    GetTransform["GetTransformAssetTypes()"]
    Central["assetTypeRelations()"]

    Discover -->|"src, label, rtype, dest"| ValidRel
    ValidRel --> GetTransform
    GetTransform --> Central

    Central --> FQDNMap["fqdnRels"]
    Central --> IPMap["ipRels"]
    Central --> OrgMap["orgRels"]
    Central --> ServiceMap["serviceRels"]

    FQDNMap --> PortLabel["'port' label"]
    FQDNMap --> DNSLabel["'dns_record' label"]
    FQDNMap --> NodeLabel["'node' label"]

    DNSLabel --> BasicDNS["BasicDNSRelation:<br/>[FQDN, IPAddress]"]
    DNSLabel --> PrefDNS["PrefDNSRelation:<br/>[FQDN]"]
    DNSLabel --> SRVDNS["SRVDNSRelation:<br/>[FQDN]"]

    PortLabel --> PortRel["PortRelation:<br/>[Service]"]

RelationType Constants¶

PropertyType Constants¶