95 lines
No EOL
3.7 KiB
Markdown
95 lines
No EOL
3.7 KiB
Markdown
# Threat analysis for the federated star activity
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## Technical Background
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### Control Flow
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```mermaid
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sequenceDiagram
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participant fs as foreign_repository_server
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participant os as our_repository_server
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fs ->> os: post /api/activitypub/repository-id/1/inbox {Start-Activity}
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activate os
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os ->> os: validate request inputs
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activate repository
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os ->> repository: validate
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repository ->> repository: search for reop with object-id
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deactivate repository
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activate person
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os ->> person: validate
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person ->> person: search for ser with actor-id
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person ->> fs: get /api/activitypub/user-id/{id from actor}
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person ->> person: create user from response
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deactivate person
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os ->> repository: execute star action
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os -->> fs: 200 ok
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deactivate os
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```
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### Data transfered
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```
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# edn notation
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{@context [
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"as": "https://www.w3.org/ns/activitystreams#",
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"forge": "https://forgefed.org/ns#",],
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::as/id "https://repo.prod.meissa.de/api/v1/activitypub/user-id/1/outbox/12345",
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::as/type "Star",
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::forge/source "forgejo",
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::as/actor "https://repo.prod.meissa.de/api/v1/activitypub/user-id/1",
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::as/object "https://codeberg.org/api/v1/activitypub/repository-id/12"
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}
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# json notation
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{"id": "https://repo.prod.meissa.de/api/v1/activitypub/user-id/1/outbox/12345",
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"type": "Star",
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"source": "forgejo",
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"actor": "https://repo.prod.meissa.de/api/v1/activitypub/user-id/1",
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"object": "https://codeberg.org/api/v1/activitypub/repository-id/1"
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}
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```
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### Data Flow
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```mermaid
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flowchart TD
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A(User) --> |stars a federated repository| B(foreign repository server)
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B --> |Star Activity| C(our repository server)
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C --> |get repository localy| D(our repos database)
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C --> |get Person Actor| B
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C --> |create federated user localy| D
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C --> |add star to repo localy| D
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```
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## Analysis
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### Assets
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1. **Service Availability**: The availability of our or foreign servers.
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2. **Reputation**: Our standing against freinds and others.
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### Actors
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1. **Script Kiddies**: Boored teens, willing to do some illigal without deep knowlege of tech details but broad knowlege across internet discussions. Able to do some bash / python scripting.
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### Threat
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1. Script Kiddi sends a Star Activity containing an attack target url `http://attacked.target/very/special/path` in place of actor. Our repository server sends an `get Person Actor` request to this url. The attacked target gets DenialdOffServices. We loose CPU & reputation.
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### DREAD-Score
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| Threat | Damage | Reproducibility | Exploitability | Affected Users | Discoverability | Mitigations |
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| :----- | :------ | :-------------- | :------------- | :------------- | :-------------- | :---------- |
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| 1. | ... tbd | | | | | |
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| 2. | ... tbd | | | | | |
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Bewertet wird mit Schulnoten von 1 - 6
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* Damage – wie groß wäre der Schaden, wenn der Angriff erfolgreich ist? 6 ist ein sehr schlimmer Schaden.
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* Reproducibility – wie einfach wäre der Angriff reproduzierbar? 6 ist sehr einfach zu reproduzieren.
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* Exploitability – wieviel Zeit, Aufwand und Erfahrung sind notwendig, um die Bedrohung auszunutzen? 6 ist sehr einfach zu machen.
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* Affected Users – wenn eine Bedrohung ausgenutzt werden würde, wieviel Prozent der Benutzer wären betroffen?
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* Discoverability – Wie einfach lässt sich ein Angriff entdecken? Muss der Angreifer Strafverfolgung erwarten? 6 ist sehr schwer zu entdecken / ist gar nicht illegal
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## Reference
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* https://geballte-sicherheit.de/threat-modelling-bedrohungsanalyse-7-teil-einstufung-von-bedrohungen-ranking-of-threats/ |