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Object Model (v1.x) (WIP)

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colesmj edited this page Jan 1, 2021 · 13 revisions

Object Types

  • TM

  • Server

  • ExternalEntity

  • DataFlow

  • Datastore

  • Actor

  • Process

  • SetOfProcesses

  • Boundary

  • Lambda

  • Data

    • CredentialsLife

    • Classification

  • Threat

  • Threats

  • Finding

Attributes

TM

The TM object is used by pytm internally to manage all the data associated with a model (for drawing and threat analysis). https://github.com/izar/pytm/blob/59822fe2b2f562d2903dfb4c7a8edf72b996d322/pytm/pytm.py#L603

Data

The Data object represents a single piece of data that traverses the system. https://github.com/izar/pytm/blob/59822fe2b2f562d2903dfb4c7a8edf72b996d322/pytm/pytm.py#L1122

Attribute Meaning Used in Threats Notes

Name

Description

Classification

What is the classification of this data

isPII

Is this data considered personally identifiable information

isCredentials

Is this data representing credentials

credentialsLife

If credentials, what is the ''lifetime'' of the data

See Enumerations section

isStored

Is this data going to be stored by the destination target

If only derived data is stored, this should be False

isDestEncryptedAtRest

Is this data encrypted at rest by the destination target

isSourceEncryptedAtRest

Is this data encrypted at rest by the source object

carriedBy

Which DataFlow objects ''carry'' this data

processedBy

Which objects will store or process this data

Element

Attribute Meaning Used in Threats Notes

name

Name of element

description

Description of element

inBoundary

The trust boundary this element resides

inScope

Boolean If this element is within the scope of the model

maxClassification

Maximum data sensitivity this element can "handle"

For some definition of "handle"

findings

Threats that apply to this element

Populated by pytm

overrides

Overrides set on findings

levels

List of levels to draw in the model for this element

Asset

An Asset is an Element (i.e. inherits all attributes from Element) that has incoming or outgoing data flows, and represents a single process or component. https://github.com/izar/pytm/blob/59822fe2b2f562d2903dfb4c7a8edf72b996d322/pytm/pytm.py#L1182

Attribute Meaning Used in Threats Notes

port

Default incoming port

Assumes TCP only, and single listening service

isEncrypted

Boolean If the incoming data flow is encrypted

Presumably by TLS (?)

protocol

Default protocol for incoming data flow

data

Default data type for incoming flow

inputs

Incoming `Dataflow`s

outputs

Outbound `Dataflow`s

onAWS

Boolean If the Asset resides on AWS

If you want to model non-AWS cloud services, subclass this.

isHardened

Boolean If the Asset is hardened

For some definition of "hardened"

implementsAuthenticationScheme

Boolean If the Asset performs some form of authentication

implementsNonce

Boolean If the Asset creates nonces for any reason

handlesResources

Boolean

(?)

definesConnectionTimeout

Boolean

(?)

authenticatesDestination

Boolean Asset verifies the target of the outbound data flow in some way

checksDestinationRevocation

Boolean If verification of target outbound flow involves certs, checks if the cert is revoked

authenticatesSource

Boolean

May be used for Mutual TLS (?)

authorizesSource

Boolean

(?)

hasAccessControl

Boolean If Asset performs any form of access control

validatesInput

Boolean If Asset validates incoming data

sanitizesInput

Boolean If Asset performs data sanitization on incoming data

checksInputBounds

Boolean If Asset checks any input data

Duplicate with validatesInput or sanitizesInput?

encodesOutput

Boolean If Asset performs any data encoding on outbound data

handlesResourceConsumption

Boolean

(?)

authenticationScheme

(?)

usesEnvironmentVariables

Boolean If Asset uses any environment variables

OS

Which OS this Asset runs on or uses

providesIntegrity

Boolean

(?)

ExternalEntity

An ExternalEntity is an Asset that represents a process or system external to the model (but with a connection to something in the model). https://github.com/izar/pytm/blob/59822fe2b2f562d2903dfb4c7a8edf72b996d322/pytm/pytm.py#L1313

Attribute Meaning Used in Threats Notes

hasPhysicalAccess

Boolean

(?)

Server

The Server object is an Asset that processes data. While this object can be used generically as a data connection unit, it is geared more for a web server of some time than a generic thing. https://github.com/izar/pytm/blob/59822fe2b2f562d2903dfb4c7a8edf72b996d322/pytm/pytm.py#L1274

Attribute Meaning Used in Threats Notes

providesConfidentiality

Boolean

(?)

providesIntegrity

Boolean

(?)

validatesHeaders

Boolean If Server validates headers in some communications

encodesHeaders

Boolean If Server encodes headers in some commnunications

implementsCSRFToken

Boolean If Server implements CSRF tokens

isResilient

Boolean

(?)

usesSessionTokens

Boolean If Server supports sessions

usesEncryptionAlgorithm

The encryption algorithm used (if any)

usesCache

Boolean

(?)

usesVPN

Boolean

(?)

usesCodeSigning

Boolean If Server artifact is digitally signed

validatesContentType

Boolean If Server validates Content-Type values

invokesScriptFilters

Boolean

(?)

usesStrongSessionIdentifiers

Boolean If Server implements strong session ids

For some definition of "strong"

usesLatestTLSversion

Boolean If Server uses the latest TLS version

TLS 1.2 and 1.3 are "latest"

implementsServerSideValidation

Boolean If Server implements validation on the server

Should be True if any validates option is True

usesXMLParser

Boolean If Server supports the parsing of XML

disablesDTD

Boolean

(?)

implementsStrictHTTPValidation

Boolean

(?)

implementsPOLP

Boolean If Server implements the Principle of Least Privilege

Contributes to isHardened (?)

Process

The Process object is an Asset that is similar to Server in that it processes data and has some common attributes. Process contains attributes commonly found in web servers, among other process types. https://github.com/izar/pytm/blob/59822fe2b2f562d2903dfb4c7a8edf72b996d322/pytm/pytm.py#L1397

Attribute Meaning Used in Threats Notes

codeType

String Type of code

"Unmanaged" is default

implementsCommunicationProtocol

Boolean

(?)

providesConfidentiality

Boolean

(?)

providesIntegrity

Boolean

(?)

isResilient

Boolean

(?)

tracksExecutionFlow

Boolean

(?)

implementsCSRFToken

Boolean If Server implements CSRF tokens

handlesResourceConsumption

Boolean

(?)

handlesCrashes

Boolean

(?)

handlesInterruptions

Boolean

(?)

implementsAPI

Boolean If Process implements an API

usesSecureFunctions

Boolean

(?)

environment

(?)

disablesiFrames

Boolean If Process disables iFrames

usesParameterizedInput

Boolean

(?)

allowsClientSideScripting

Boolean

(?)

encryptsCookies

Boolean If Process encrypts cookies that it sets

usesMFA

Boolean If Process uses multi-factor authentication for incoming requests or session establishment

encryptsSessionData

Boolean If Process encrypts session data it sets

verifySessionIdentifiers

Boolean If Process verifies session ids it sets

usesStrongSessionIdentifiers

Boolean If Server implements strong session ids

For some definition of "strong"

implementsPOLP

Boolean If Server implements the Principle of Least Privilege

Contributes to isHardened (?)

Enumerations

CredentialsLife

The CredentialsLife attribute represents the lifetime or revocation process for data that are credentials, and uses the Lifetime enum.

Attribute Meaning Used in Threats Notes

NONE

Not Applicable

UNKNOWN

Unknown lifetime or revocation process

SHORT

Short lived (for some definition of short)

LONG

Long lived (for some definition of long)

If forever (equivalent to HARDCODED?)

AUTO

Long lived with no expiration but can be invalidated by some automatic process

MANUAL

Long lived with no expiration but can be invalidated by some manual process

HARDCODED

Long lived - forever, cannot be invalidated

Classification

The Classification enum represents the sensitivity of Data, based some understanding of the user as to the relative sensitivity levels defined by pytm. For example, "Public" data may be still kept within the confines of a certain set of users, or may be for general consumption (aka "public facing").

Attribute Meaning Used in Threats Notes

UNKNOWN

Unknown sensitivity

Default

PUBLIC

Information which can be shared for "public" consumption

User defines what "public" represents to them

RESTRICTED

SENSITIVE

SECRET

TOP_SECRET
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