Tor browser exploit accepted

THREAT79 · Accepted: The team has decided to live with this risk. · Defined in catalog.py:1392

Risk: High impact × Very Low likelihood = 3 low
After mitigations: High impact × Very Low likelihood = 3 low (unchanged)

Source Tor browser is compromised due to a Tor browser exploit being used.

Threat actors: Nation State / Law Enforcement

Mitigations

Mitigation	Status
Tor security slider set to high MITIG67	optional

Possible further mitigations

Source guide and interface should strongly warn about out of date TB MITIG221 proposed

Residual risk

Adversary can just disable warning in SecureDrop

Where it applies

Applies to 1 component in 1 scenario.

Source Tor Browser Source Area

Source discovery and OPSEC · Source Tor Browser

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;
        ]

    }

    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;

            style = "filled";

            fillcolor = "#c0392b";

            fontcolor = "white";

            class = "highlighted";
        ]

        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: Source interface banner suggests that user disables JS (high security settings in Tor Browser) (MITIG67). Further mitigations: Source guide should be updated to recommend sources update their Tor Browser if prompted for an update (MITIG221). Automated test for mitigation: No.

How this threat is matched

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