CAPEC-263: Force Use of Corrupted Files

This describes an attack where an application is forced to use a file that an attacker has corrupted. The result is often a denial of service caused by the application being unable to process the corrupted file, but other results, including the disabling of filters or access controls (if the application fails in an unsafe way rather than failing by locking down) or buffer overflows are possible.

Medium

Severity

occurrences in scenarios

Frequency

Affected Components

Affected Scenarios

Requirements and Mitigations

Requirements

Component properties that must be true for this threat to apply:

Mitigations

Component properties that mitigate this threat:

Affected Components

Component	Description	Boundary
doc_to_pixels.py	Reads a suspicious documents and converts it to pixels	gVisor sandbox
LibreOffice	Converts documents to PDFs	gVisor sandbox

Affected Scenarios

convert — affects: doc_to_pixels.py LibreOffice

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

    subgraph cluster_boundary_Internet {
        graph [
            fontsize = 10;
            fontcolor = black;
            style = dashed;
            color = firebrick2;
            label = <Internet>;
        ]

        externalentity_Random_doc_source_Internet [
            shape = square;
            color = black;
            fontcolor = black;
            label = "Random doc\nsource";
            URL = "component_Random_doc_source.html";
            tooltip = "Random doc source";
            margin = 0.02;
        ]

    }

    subgraph cluster_boundary_Local_host {
        graph [
            fontsize = 10;
            fontcolor = black;
            style = dashed;
            color = firebrick2;
            label = <Local host>;
        ]

        subgraph cluster_boundary_Docker_Podman_VM {
            graph [
                fontsize = 10;
                fontcolor = black;
                style = dashed;
                color = firebrick2;
                label = <Docker/Podman VM>;
            ]

            subgraph cluster_boundary_Outer_container {
                graph [
                    fontsize = 10;
                    fontcolor = black;
                    style = dashed;
                    color = firebrick2;
                    label = <Outer container>;
                ]

                subgraph cluster_boundary_gVisor_sandbox {
                    graph [
                        fontsize = 10;
                        fontcolor = black;
                        style = dashed;
                        color = firebrick2;
                        label = <gVisor sandbox>;
                    ]

                    component_LibreOffice_gVisor_sandbox [
                        shape = circle;
                        color = black;
                        fontcolor = black;
                        label = "LibreOffice";
                        URL = "component_LibreOffice.html";
                        tooltip = "LibreOffice";
                        margin = 0.02;

                        style = "filled";

                        fillcolor = "#c0392b";

                        fontcolor = "white";

                        class = "highlighted";
                    ]

                    component_doc_to_pixels_py_gVisor_sandbox [
                        shape = circle;
                        color = black;
                        fontcolor = black;
                        label = "doc_to_pixels.py";
                        URL = "component_doc_to_pixels_py.html";
                        tooltip = "doc_to_pixels.py";
                        margin = 0.02;

                        style = "filled";

                        fillcolor = "#c0392b";

                        fontcolor = "white";

                        class = "highlighted";
                    ]

                }

                component_entrypoint_py_Outer_container [
                    shape = circle;
                    color = black;
                    fontcolor = black;
                    label = "entrypoint.py";
                    URL = "component_entrypoint_py.html";
                    tooltip = "entrypoint.py";
                    margin = 0.02;
                ]

            }

            component_Container_runtime_Docker_Podman_VM [
                shape = circle;
                color = black;
                fontcolor = black;
                label = "Container\nruntime";
                URL = "component_Container_runtime.html";
                tooltip = "Container runtime";
                margin = 0.02;
            ]

        }

        component_Container_manager_Local_host [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "Container\nmanager";
            URL = "component_Container_manager.html";
            tooltip = "Container manager";
            margin = 0.02;
        ]

        component_DZ_App_Local_host [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "DZ App";
            URL = "component_DZ_App.html";
            tooltip = "DZ App";
            margin = 0.02;
        ]

        datastore_Host_storage_Local_host [
            shape = cylinder;
            color = black;
            fontcolor = black;
            label = "Host storage";
            URL = "component_Host_storage.html";
            tooltip = "Host storage";
            margin = 0.02;
        ]

        component_PDF_reader_Local_host [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "PDF reader";
            URL = "component_PDF_reader.html";
            tooltip = "PDF reader";
            margin = 0.02;
        ]

        actor_User_Local_host [
            shape = square;
            color = black;
            fontcolor = black;
            label = "User";
            URL = "component_User.html";
            tooltip = "User";
            margin = 0.02;
        ]

    }

    actor_User_Local_host -> externalentity_Random_doc_source_Internet [        color = black;        fontcolor = black;        dir = forward;        label = "1. Request untrusted\ndoc from remote\nsource";    ]
    externalentity_Random_doc_source_Internet -> datastore_Host_storage_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "2. Receive untrusted\ndoc from remote\nsource and store it\nlocally";    ]
    actor_User_Local_host -> component_DZ_App_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "3. Start the\nDangerzone App";    ]
    component_DZ_App_Local_host -> component_Container_manager_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "4. Invoke\nDocker/Podman to\ncheck if the\ncontainer image is\npresent and\ninstalled";    ]
    component_Container_manager_Local_host -> component_Container_runtime_Docker_Podman_VM [        color = black;        fontcolor = black;        dir = forward;        label = "5. Is the image\npresent in the VM?";    ]
    component_Container_runtime_Docker_Podman_VM -> component_Container_manager_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "6. Image is present";    ]
    component_Container_manager_Local_host -> component_DZ_App_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "7. Reply to\nDangerzone APP that\nthe container image\nis installed";    ]
    actor_User_Local_host -> component_DZ_App_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "8. Select documents\nfor conversion";    ]
    component_DZ_App_Local_host -> component_Container_manager_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "9. Request a Linux\ncontainer for\nconversion";    ]
    component_Container_manager_Local_host -> component_Container_runtime_Docker_Podman_VM [        color = black;        fontcolor = black;        dir = forward;        label = "10. Start a Linux\ncontainer";    ]
    component_Container_runtime_Docker_Podman_VM -> component_entrypoint_py_Outer_container [        color = black;        fontcolor = black;        dir = forward;        label = "11. Run entrypoint\nscript of Linux\ncontainer";    ]
    component_entrypoint_py_Outer_container -> component_doc_to_pixels_py_gVisor_sandbox [        color = black;        fontcolor = black;        dir = forward;        label = "12. Start the\nDangerzone converter\nin the gVisor\nsandbox";    ]
    component_DZ_App_Local_host -> component_doc_to_pixels_py_gVisor_sandbox [        color = black;        fontcolor = black;        dir = forward;        label = "13. Send the\nsuspicious document\nto the stdin of the\ngVisor sandbox";    ]
    component_doc_to_pixels_py_gVisor_sandbox -> component_LibreOffice_gVisor_sandbox [        color = black;        fontcolor = black;        dir = forward;        label = "14. Convert the\nsuspicious doc to\nPDF (if not already)";    ]
    component_LibreOffice_gVisor_sandbox -> component_doc_to_pixels_py_gVisor_sandbox [        color = black;        fontcolor = black;        dir = forward;        label = "15. Receive\nsuspicious doc as\nPDF";    ]
    component_doc_to_pixels_py_gVisor_sandbox -> component_DZ_App_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "16. Rasterize PDF\ninto pixels and\nwrite them to the\ngVisor sandbox's\nstdout";    ]
    component_DZ_App_Local_host -> datastore_Host_storage_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "17. Reconstruct a\nsafe doc from pixels\nto PDF (and\noptionally OCR it)";    ]
    component_DZ_App_Local_host -> datastore_Host_storage_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "18. Save safe PDF\nwith a '-safe.pdf'\nprefix";    ]
    component_DZ_App_Local_host -> datastore_Host_storage_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "19. Archive the\nsuspicious PDF into\nthe 'unsafe/'\ndirectory";    ]
    component_DZ_App_Local_host -> component_PDF_reader_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "20. Open the PDF\nusing the program of\nthe user's choice,\nor the default one";    ]
}

convert_basic — affects: doc_to_pixels.py

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

    subgraph cluster_boundary_Local_host {
        graph [
            fontsize = 10;
            fontcolor = black;
            style = dashed;
            color = firebrick2;
            label = <Local host>;
        ]

        subgraph cluster_boundary_Docker_Podman_VM {
            graph [
                fontsize = 10;
                fontcolor = black;
                style = dashed;
                color = firebrick2;
                label = <Docker/Podman VM>;
            ]

            subgraph cluster_boundary_Outer_container {
                graph [
                    fontsize = 10;
                    fontcolor = black;
                    style = dashed;
                    color = firebrick2;
                    label = <Outer container>;
                ]

                subgraph cluster_boundary_gVisor_sandbox {
                    graph [
                        fontsize = 10;
                        fontcolor = black;
                        style = dashed;
                        color = firebrick2;
                        label = <gVisor sandbox>;
                    ]

                    component_doc_to_pixels_py_gVisor_sandbox [
                        shape = circle;
                        color = black;
                        fontcolor = black;
                        label = "doc_to_pixels.py";
                        URL = "component_doc_to_pixels_py.html";
                        tooltip = "doc_to_pixels.py";
                        margin = 0.02;

                        style = "filled";

                        fillcolor = "#c0392b";

                        fontcolor = "white";

                        class = "highlighted";
                    ]

                }

            }

        }

        component_DZ_App_Local_host [
            shape = circle;
            color = black;
            fontcolor = black;
            label = "DZ App";
            URL = "component_DZ_App.html";
            tooltip = "DZ App";
            margin = 0.02;
        ]

        datastore_Host_storage_Local_host [
            shape = cylinder;
            color = black;
            fontcolor = black;
            label = "Host storage";
            URL = "component_Host_storage.html";
            tooltip = "Host storage";
            margin = 0.02;
        ]

        actor_User_Local_host [
            shape = square;
            color = black;
            fontcolor = black;
            label = "User";
            URL = "component_User.html";
            tooltip = "User";
            margin = 0.02;
        ]

    }

    actor_User_Local_host -> component_DZ_App_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "1. Start the\nDangerzone App";    ]
    actor_User_Local_host -> component_DZ_App_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "2. Select documents\nfor conversion";    ]
    component_DZ_App_Local_host -> component_doc_to_pixels_py_gVisor_sandbox [        color = black;        fontcolor = black;        dir = forward;        label = "3. Send the\nsuspicious document\nto the stdin of the\ngVisor sandbox";    ]
    component_doc_to_pixels_py_gVisor_sandbox -> component_DZ_App_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "4. Rasterize PDF\ninto pixels and\nwrite them to the\ngVisor sandbox's\nstdout";    ]
    component_DZ_App_Local_host -> datastore_Host_storage_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "5. Reconstruct a\nsafe doc from pixels\nto PDF (and\noptionally OCR it)";    ]
    component_DZ_App_Local_host -> datastore_Host_storage_Local_host [        color = black;        fontcolor = black;        dir = forward;        label = "6. Save safe PDF\nwith a '-safe.pdf'\nprefix";    ]
}

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