DNS partially mitigated

THREAT85 · Partially mitigated: Some controls are in place, but the risk is still too high. · Defined in catalog.py:1473

Risk: High impact × Medium likelihood = 9 high
After mitigations: High impact × Medium likelihood = 9 high (unchanged)

How statuses and scores work

An attacker with a privileged network position could spoof/tamper DNS response and cause DoS or attempt to MiTM network connections.

Threat actors: Nation State / Law Enforcement Large Corporation

Mitigations

Mitigation	Status
Source interface only available as a Tor onion service MITIG54	implemented
Journalist interface only available as a Tor onion service MITIG55	implemented
Admin interface traffic goes over Tor MITIG96	implemented

Possible further mitigations

DNS over TLS MITIG90 proposed
Apt traffic over Tor MITIG91 proposed
Use authenticated version of NTP to harden against e.g. DNS attacks - tlsdate? research needed here MITIG97 proposed

Residual risk

Candidate for further mitigation efforts

Where it applies

Applies to 1 component in 1 scenario.

DNS resolver External Services

Updates, time & DNS · DNS resolver

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;

            style = "filled";

            fillcolor = "#c0392b";

            fontcolor = "white";

            class = "highlighted";
        ]

        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;
        ]

    }

    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";    ]
}

Notes

Existing mitigations: Most traffic is routed over Tor Hidden services (end-to-end encrypted) (MITIG54, MITIG55, MITIG96). Only clearnet traffic is Apt (where packages are GPG-signed), DNS, NTP, and mail (GPG-encrypted). Further mitigations: DNS over tls (https://datatracker.ietf.org/doc/rfc7858/) (MITIG90), send apt traffic over Tor (MITIG91), harden NTP (MITIG97). Automated test for mitigation: No.

How this threat is matched

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