Failure to encrypt submissions as they are written to disk mitigated

THREAT21 · Mitigated: Controls in place bring the risk down to an acceptable level. · Defined in catalog.py:377

Risk: Medium impact × Low likelihood = 4 medium
After mitigations: Medium impact × Low likelihood = 4 medium (unchanged)

Failure to encrypt files as they are streamed to a temporary file through Secure Temporary File wrapper as the files are streamed on disk prior to being encrypted by RSA may lead to decrypted documents being persisted to disc and potentially viewable through forensic investigation of app server hardware or remote access to the app server.

Threat actors: Any

Mitigations

Mitigation	Status
Logging off for source interface MITIG41	implemented

Possible further mitigations

FDE on app/mon servers MITIG134 proposed

Where it applies

Applies to 1 component in 2 scenarios.

Source Interface Application Server

Source submission · Source Interface

digraph tm {
    graph [
        fontname = Arial;
        fontsize = 14;
    ]
    node [
        fontname = Arial;
        fontsize = 14;
    ]
    edge [
        fontname = Arial;
        fontsize = 12;
    ]
    nodesep = 1;

    subgraph cluster_boundary_Application_Server {
        graph [
            fontsize = 10;
            fontcolor = black;
            style = dashed;
            color = firebrick2;
            label = <<i>Application Server</i>>;
        ]

        component_Encrypted_submission_store_Application_Server [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "Encrypted\nsubmission store";
            URL = "component_Encrypted_submission_store.html";
            tooltip = "Encrypted submission store";
            margin = 0.02;
        ]

        component_Metadata_DB_Application_Server [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "Metadata DB";
            URL = "component_Metadata_DB.html";
            tooltip = "Metadata DB";
            margin = 0.02;
        ]

        component_SecureDrop_Application_Application_Server [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "SecureDrop\nApplication";
            URL = "component_SecureDrop_Application.html";
            tooltip = "SecureDrop Application";
            margin = 0.02;
        ]

        component_Source_Interface_Application_Server [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "Source Interface";
            URL = "component_Source_Interface.html";
            tooltip = "Source Interface";
            margin = 0.02;

            style = "filled";

            fillcolor = "#c0392b";

            fontcolor = "white";

            class = "highlighted";
        ]

    }

    subgraph cluster_boundary_SecureDrop_Area {
        graph [
            fontsize = 10;
            fontcolor = black;
            style = dashed;
            color = firebrick2;
            label = <<i>SecureDrop Area</i>>;
        ]

        component_Dedicated_Hardware_Firewall_SecureDrop_Area [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "Dedicated\nHardware\nFirewall";
            URL = "component_Dedicated_Hardware_Firewall.html";
            tooltip = "Dedicated Hardware Firewall";
            margin = 0.02;
        ]

    }

    subgraph cluster_boundary_Source_Area {
        graph [
            fontsize = 10;
            fontcolor = black;
            style = dashed;
            color = firebrick2;
            label = <<i>Source Area</i>>;
        ]

        actor_Source_Source_Area [
            shape = square;
            color = black;
            fontcolor = black;
            label = "Source";
            URL = "component_Source.html";
            tooltip = "Source";
            margin = 0.02;
        ]

    }

    actor_Source_Source_Area -> component_Dedicated_Hardware_Firewall_SecureDrop_Area [        color = black;        fontcolor = black;        dir = forward;        label = "1. Submit over Tor";    ]
    component_Dedicated_Hardware_Firewall_SecureDrop_Area -> component_Source_Interface_Application_Server [        color = black;        fontcolor = black;        dir = forward;        label = "2. Reach Source\nInterface";    ]
    component_Source_Interface_Application_Server -> component_SecureDrop_Application_Application_Server [        color = black;        fontcolor = black;        dir = forward;        label = "3. Hand to app";    ]
    component_SecureDrop_Application_Application_Server -> component_Encrypted_submission_store_Application_Server [        color = black;        fontcolor = black;        dir = forward;        label = "4. Encrypt & store";    ]
    component_SecureDrop_Application_Application_Server -> component_Metadata_DB_Application_Server [        color = black;        fontcolor = black;        dir = forward;        label = "5. Record metadata";    ]
}

Supply chain and dependencies · Source Interface

digraph tm {
    graph [
        fontname = Arial;
        fontsize = 14;
    ]
    node [
        fontname = Arial;
        fontsize = 14;
    ]
    edge [
        fontname = Arial;
        fontsize = 12;
    ]
    nodesep = 1;

    subgraph cluster_boundary_Application_Server {
        graph [
            fontsize = 10;
            fontcolor = black;
            style = dashed;
            color = firebrick2;
            label = <<i>Application Server</i>>;
        ]

        component_App_Server_APT_NTP_DNS_Application_Server [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "App Server\nAPT/NTP/DNS";
            URL = "component_App_Server_APT_NTP_DNS.html";
            tooltip = "App Server APT/NTP/DNS";
            margin = 0.02;
        ]

        component_Source_Interface_Application_Server [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "Source Interface";
            URL = "component_Source_Interface.html";
            tooltip = "Source Interface";
            margin = 0.02;

            style = "filled";

            fillcolor = "#c0392b";

            fontcolor = "white";

            class = "highlighted";
        ]

    }

    subgraph cluster_boundary_External_Services {
        graph [
            fontsize = 10;
            fontcolor = black;
            style = dashed;
            color = firebrick2;
            label = <<i>External Services</i>>;
        ]

        component_FPF_apt_repository_External_Services [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "FPF apt\nrepository";
            URL = "component_FPF_apt_repository.html";
            tooltip = "FPF apt repository";
            margin = 0.02;
        ]

        component_SecureDrop_release___package_build_External_Services [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "SecureDrop\nrelease &\npackage build";
            URL = "component_SecureDrop_release___package_build.html";
            tooltip = "SecureDrop release & package build";
            margin = 0.02;
        ]

        component_SecureDrop_source_repository_External_Services [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "SecureDrop\nsource\nrepository";
            URL = "component_SecureDrop_source_repository.html";
            tooltip = "SecureDrop source repository";
            margin = 0.02;
        ]

        component_Tor_software_External_Services [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "Tor software";
            URL = "component_Tor_software.html";
            tooltip = "Tor software";
            margin = 0.02;
        ]

        component_Ubuntu_apt_repository_External_Services [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "Ubuntu apt\nrepository";
            URL = "component_Ubuntu_apt_repository.html";
            tooltip = "Ubuntu apt repository";
            margin = 0.02;
        ]

    }

    component_SecureDrop_source_repository_External_Services -> component_SecureDrop_release___package_build_External_Services [        color = black;        fontcolor = black;        dir = forward;        label = "1. Build from source";    ]
    component_SecureDrop_release___package_build_External_Services -> component_FPF_apt_repository_External_Services [        color = black;        fontcolor = black;        dir = forward;        label = "2. Publish packages";    ]
    component_FPF_apt_repository_External_Services -> component_App_Server_APT_NTP_DNS_Application_Server [        color = black;        fontcolor = black;        dir = forward;        label = "3. Install / update";    ]
    component_Ubuntu_apt_repository_External_Services -> component_App_Server_APT_NTP_DNS_Application_Server [        color = black;        fontcolor = black;        dir = forward;        label = "4. Ubuntu\ndependencies";    ]
    component_Tor_software_External_Services -> component_Source_Interface_Application_Server [        color = black;        fontcolor = black;        dir = forward;        label = "5. Tor dependency";    ]
}

Notes

Existing mitigations: Sensitive information (source information, submission information) is not logged (MITIG41). Further mitigations: Application and mon servers should be encrypted at rest (MITIG134). Automated test for mitigation: Yes.

How this threat is matched

Listed for these components. A boundary covers every component inside it.