Vulnerabilities/Compromise of Hardware Firewall mitigated

THREAT48 · Mitigated: Controls in place bring the risk down to an acceptable level. · Defined in catalog.py:852

Risk: Medium impact × Low likelihood = 4 medium
After mitigations: Low impact × Low likelihood = 2 low

An adversary that has compromised the hardware firewall will be able to eavesdrop/inject network traffic to and from the SecureDrop Application and Monitoring servers. It may also directly attack and attempt to compromise the app or mon servers. An adversary that has compromised the hardware firewall also can launch browser attacks against the user of the cleartext browser in the Admin workstation.

Threat actors: Nation State / Law Enforcement Large Corporation

Mitigations

Mitigation	Status
apt performs GPG signature verification as long as it's not explicitly disabled MITIG167	implemented
Restrictive iptables rules on servers MITIG182	implemented
Admins instructed to subscribe to RSS feed MITIG196	implemented
app, mon server cannot access admin interface of hardware firewall MITIG239	implemented
Source interface only available as a Tor onion service MITIG54	implemented
Journalist interface only available as a Tor onion service MITIG55	implemented

Possible further mitigations

Send warnings from FPF for pfSense updates MITIG197 proposed

Residual risk

Potential replay of old Apt packages and denial of service through NTP (Tor will fail to complete circuit if the clock is not accurate). DNS and NTP are transmitted over HTTP (unauthenticated and in cleartext).

Where it applies

Applies to 1 component in 5 scenarios.

Dedicated Hardware Firewall SecureDrop Area

Source submission · Dedicated Hardware Firewall

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;
        ]

    }

    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;

            style = "filled";

            fillcolor = "#c0392b";

            fontcolor = "white";

            class = "highlighted";
        ]

    }

    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";    ]
}

Journalist triage · Dedicated Hardware Firewall

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_Journalist_Interface_Application_Server [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "Journalist\nInterface";
            URL = "component_Journalist_Interface.html";
            tooltip = "Journalist Interface";
            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;
        ]

    }

    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;

            style = "filled";

            fillcolor = "#c0392b";

            fontcolor = "white";

            class = "highlighted";
        ]

    }

    actor_Journalist_ [
        shape = square;
        color = black;
        fontcolor = black;
        label = "Journalist";
        URL = "component_Journalist.html";
        tooltip = "Journalist";
        margin = 0.02;
    ]

    actor_Journalist_ -> component_Dedicated_Hardware_Firewall_SecureDrop_Area [        color = black;        fontcolor = black;        dir = forward;        label = "1. Authenticate over\nTor";    ]
    component_Dedicated_Hardware_Firewall_SecureDrop_Area -> component_Journalist_Interface_Application_Server [        color = black;        fontcolor = black;        dir = forward;        label = "2. Reach Journalist\nInterface";    ]
    component_Journalist_Interface_Application_Server -> component_Metadata_DB_Application_Server [        color = black;        fontcolor = black;        dir = forward;        label = "3. List sources";    ]
    component_Encrypted_submission_store_Application_Server -> actor_Journalist_ [        color = black;        fontcolor = black;        dir = forward;        label = "4. Download\nencrypted";    ]
}

Admin access · Dedicated Hardware Firewall

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_SSH_Application_Server [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "App Server SSH";
            URL = "component_App_Server_SSH.html";
            tooltip = "App Server SSH";
            margin = 0.02;
        ]

    }

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

        component_Monitor_Server_SSH_Monitoring_Server [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "Monitor Server\nSSH";
            URL = "component_Monitor_Server_SSH.html";
            tooltip = "Monitor Server SSH";
            margin = 0.02;
        ]

    }

    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;

            style = "filled";

            fillcolor = "#c0392b";

            fontcolor = "white";

            class = "highlighted";
        ]

    }

    actor_Administrator_ [
        shape = square;
        color = black;
        fontcolor = black;
        label = "Administrator";
        URL = "component_Administrator.html";
        tooltip = "Administrator";
        margin = 0.02;
    ]

    actor_Administrator_ -> component_Dedicated_Hardware_Firewall_SecureDrop_Area [        color = black;        fontcolor = black;        dir = forward;        label = "1. SSH over Tor";    ]
    component_Dedicated_Hardware_Firewall_SecureDrop_Area -> component_App_Server_SSH_Application_Server [        color = black;        fontcolor = black;        dir = forward;        label = "2. Admin App Server";    ]
    component_Dedicated_Hardware_Firewall_SecureDrop_Area -> component_Monitor_Server_SSH_Monitoring_Server [        color = black;        fontcolor = black;        dir = forward;        label = "3. Admin Monitor\nServer";    ]
}

Updates, time & DNS · Dedicated Hardware Firewall

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;
        ]

    }

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

        component_DNS_resolver_External_Services [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "DNS resolver";
            URL = "component_DNS_resolver.html";
            tooltip = "DNS resolver";
            margin = 0.02;
        ]

        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_NTP_server_External_Services [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "NTP server";
            URL = "component_NTP_server.html";
            tooltip = "NTP server";
            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;
        ]

    }

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

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

    }

    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;

            style = "filled";

            fillcolor = "#c0392b";

            fontcolor = "white";

            class = "highlighted";
        ]

    }

    component_App_Server_APT_NTP_DNS_Application_Server -> component_Monitor_Server_APT_NTP_DNS_Monitoring_Server [        color = black;        fontcolor = black;        dir = forward;        label = "1. Proxy via monitor";    ]
    component_Monitor_Server_APT_NTP_DNS_Monitoring_Server -> component_Dedicated_Hardware_Firewall_SecureDrop_Area [        color = black;        fontcolor = black;        dir = forward;        label = "2. Egress via\nfirewall";    ]
    component_Dedicated_Hardware_Firewall_SecureDrop_Area -> component_Ubuntu_apt_repository_External_Services [        color = black;        fontcolor = black;        dir = forward;        label = "3. Ubuntu apt";    ]
    component_Dedicated_Hardware_Firewall_SecureDrop_Area -> component_FPF_apt_repository_External_Services [        color = black;        fontcolor = black;        dir = forward;        label = "4. FPF apt";    ]
    component_Dedicated_Hardware_Firewall_SecureDrop_Area -> component_NTP_server_External_Services [        color = black;        fontcolor = black;        dir = forward;        label = "5. NTP";    ]
    component_Dedicated_Hardware_Firewall_SecureDrop_Area -> component_DNS_resolver_External_Services [        color = black;        fontcolor = black;        dir = forward;        label = "6. DNS";    ]
}

Source discovery and OPSEC · Dedicated Hardware Firewall

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

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

        component_Landing_page_External_Services [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "Landing page";
            URL = "component_Landing_page.html";
            tooltip = "Landing page";
            margin = 0.02;
        ]

        component_SecureDrop_org_directory_External_Services [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "SecureDrop.org\ndirectory";
            URL = "component_SecureDrop_org_directory.html";
            tooltip = "SecureDrop.org directory";
            margin = 0.02;
        ]

    }

    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;

            style = "filled";

            fillcolor = "#c0392b";

            fontcolor = "white";

            class = "highlighted";
        ]

    }

    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;
        ]

        component_Source_Tor_Browser_Source_Area [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "Source Tor\nBrowser";
            URL = "component_Source_Tor_Browser.html";
            tooltip = "Source Tor Browser";
            margin = 0.02;
        ]

        component_Source_environment_Source_Area [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "Source\nenvironment";
            URL = "component_Source_environment.html";
            tooltip = "Source environment";
            margin = 0.02;
        ]

    }

    actor_Source_Source_Area -> component_Source_environment_Source_Area [        color = black;        fontcolor = black;        dir = forward;        label = "1. Research / browse";    ]
    component_Source_environment_Source_Area -> component_SecureDrop_org_directory_External_Services [        color = black;        fontcolor = black;        dir = forward;        label = "2. Check directory";    ]
    component_Source_environment_Source_Area -> component_Landing_page_External_Services [        color = black;        fontcolor = black;        dir = forward;        label = "3. Visit landing\npage";    ]
    actor_Source_Source_Area -> component_Source_Tor_Browser_Source_Area [        color = black;        fontcolor = black;        dir = forward;        label = "4. Open Tor Browser";    ]
    component_Source_Tor_Browser_Source_Area -> component_Dedicated_Hardware_Firewall_SecureDrop_Area [        color = black;        fontcolor = black;        dir = forward;        label = "5. Connect to onion";    ]
}

Notes

Existing mitigations: APT packages are signed (MITIG167). iptables is used as a Host-based firewall on app and mon servers (MITIG182). Senstive data is exchanged over encrypted and authenticated channel (Tor). SecureDrop admin guide (https://docs.securedrop.org/en/stable/admin.html) informs administrators to update the hardware firewall (MITIG196). Provides a very restrictive policy for accessing the administrative interface (blocked on app and mon ports of the firewall) (MITIG239). App and Mon servers use IPTables as host-based firewall for defense-in-depth (MITIG182). All application traffic is over Tor Hidden services (end-to-end encrypted) (MITIG54, MITIG55). All software packages are signed (MITIG167). Further mitigations: FPF should inform organizations when a critical pfSense update should be made as pfSense is recommended in the documentation (MITIG197). Automated test for mitigation: No.

How this threat is matched

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