Bookmarks to WinDbg breakpoints

Purpose

This notebook and script are designed to convert the bookmarks of a scenario to WinDbg breakpoints. The meat of the script uses the ability of the API to iterate on the bookmarks of a Reven scenario, as well as the OSSI location, to generate a list of breakpoint commands for WinDbg where the addresses are independent of the Reven scenario itself:

for bookmark in self._server.bookmarks.all():
location = bookmark.transition.context_before().ossi.location()
print(f"bp {location.binary.name}+{location.rva:#x}\r\n")

The output of the script is a list of WinDbg breakpoint commands corresponding to the relative virtual address of the location of each of the bookmarks. This list of command can either be copy-pasted in WinDbg or output to a file, which can then be executed in WinDbg using the following syntax:

$<breakpoints.txt

How to use

Bookmark can be converted from this notebook or from the command line. The script can also be imported as a module for use from your own script or notebook.

From the notebook

  1. Upload the bk2bp.ipynb file in Jupyter.
  2. Fill out the parameters cell of this notebook according to your scenario and desired output.
  3. Run the full notebook.

From the command line

  1. Make sure that you are in an environment that can run Reven scripts.
  2. Run python bk2bp.py --help to get a tour of available arguments.
  3. Run python bk2bp.py --host <your_host> --port <your_port> [<other_option>] with your arguments of choice.

Imported in your own script or notebook

  1. Make sure that you are in an environment that can run Reven scripts.
  2. Make sure that bk2bp.py is in the same directory as your script or notebook.
  3. Add import bk2bp to your script or notebook. You can access the various functions and classes exposed by the module from the bk2bp namespace.
  4. Refer to the Argument parsing cell for an example of use in a script, and to the Parameters cell and below for an example of use in a notebook (you just need to preprend bk2bp in front of the functions and classes from the script).

Known limitations

  • For the breakpoints to be resolved by WinDbg, the debugged program/machine/Reven scenario needs to be in a state where the corresponding modules have been loaded. Otherwise, WinDbg will add the breakpoints in an unresolved state, and may mixup module and symbols.
  • When importing breakpoints generated from the bookmarks of a scenario using this script in WinDbg, make sure that the debugged system is "similar enough" to the VM that was used to record the scenario. In particular, if a binary changed and has symbols at different offsets in the debugged system, importing the breakpoints will not lead to the correct location in the binary, and may render the debugged system unstable.

Supported versions

Reven 2.8+

Supported perimeter

Any Windows Reven scenario.

Dependencies

The script requires that the target Reven scenario have:

  • The Fast Search feature replayed.
  • The OSSI feature replayed.

Source

# ---
# jupyter:
#   jupytext:
#     formats: ipynb,py:percent
#     text_representation:
#       extension: .py
#       format_name: percent
#   kernelspec:
#     display_name: reven
#     language: python
#     name: reven-python3
# ---

# %% [markdown]
# # Bookmarks to WinDbg breakpoints
#
# ## Purpose
#
# This notebook and script are designed to convert the bookmarks of a scenario to WinDbg breakpoints.
#
# The meat of the script uses the ability of the API to iterate on the bookmarks of a Reven scenario, as well as the
# OSSI location, to generate a list of breakpoint commands for WinDbg where the addresses are independent of the Reven
# scenario itself:
#
# ```py
# for bookmark in self._server.bookmarks.all():
#     location = bookmark.transition.context_before().ossi.location()
#     print(f"bp {location.binary.name}+{location.rva:#x}\r\n")
# ```
#
# The output of the script is a list of WinDbg breakpoint commands corresponding to the relative virtual address
# of the location of each of the bookmarks.
#
# This list of command can either be copy-pasted in WinDbg or output to a file, which can then be executed in WinDbg
# using the following syntax:
#
# ```kd
# $<breakpoints.txt
# ```
#
# ## How to use
#
# Bookmark can be converted from this notebook or from the command line.
# The script can also be imported as a module for use from your own script or notebook.
#
#
# ### From the notebook
#
# 1. Upload the `bk2bp.ipynb` file in Jupyter.
# 2. Fill out the [parameters](#Parameters) cell of this notebook according to your scenario and desired output.
# 3. Run the full notebook.
#
#
# ### From the command line
#
# 1. Make sure that you are in an environment that can run Reven scripts.
# 2. Run `python bk2bp.py --help` to get a tour of available arguments.
# 3. Run `python bk2bp.py --host <your_host> --port <your_port> [<other_option>]` with your arguments of
#    choice.
#
# ### Imported in your own script or notebook
#
# 1. Make sure that you are in an environment that can run Reven scripts.
# 2. Make sure that `bk2bp.py` is in the same directory as your script or notebook.
# 3. Add `import bk2bp` to your script or notebook. You can access the various functions and classes
#    exposed by the module from the `bk2bp` namespace.
# 4. Refer to the [Argument parsing](#Argument-parsing) cell for an example of use in a script, and to the
#    [Parameters](#Parameters) cell and below for an example of use in a notebook (you just need to preprend
#    `bk2bp` in front of the functions and classes from the script).
#
# ## Known limitations
#
# - For the breakpoints to be resolved by WinDbg, the debugged program/machine/Reven scenario needs to be in a state
# where the corresponding modules have been loaded. Otherwise, WinDbg will add the breakpoints in an unresolved state,
#   and may mixup module and symbols.
#
# - When importing breakpoints generated from the bookmarks of a scenario using this script in WinDbg,
#   make sure that the debugged system is "similar enough" to the VM that was used to record the scenario.
#   In particular, if a binary changed and has symbols at different offsets in the debugged system, importing
#   the breakpoints will not lead to the correct location in the binary, and may render the debugged system unstable.
#
# ## Supported versions
#
# Reven 2.8+
#
# ## Supported perimeter
#
# Any Windows Reven scenario.
#
# ## Dependencies
#
# The script requires that the target Reven scenario have:
#
# * The Fast Search feature replayed.
# * The OSSI feature replayed.

# %% [markdown]
# ### Package imports

# %%
import argparse
from typing import Optional

import reven2  # type: ignore


# %% [markdown]
# ### Utility functions


# %%
# Detect if we are currently running a Jupyter notebook.
#
# This is used e.g. to display rendered results inline in Jupyter when we are executing in the context of a Jupyter
# notebook, or to display raw results on the standard output when we are executing in the context of a script.
def in_notebook():
    try:
        from IPython import get_ipython  # type: ignore

        if get_ipython() is None or ("IPKernelApp" not in get_ipython().config):
            return False
    except ImportError:
        return False
    return True


# %% [markdown]
# ### Main function


# %%
def bk2bp(server: reven2.RevenServer, output: Optional[str]):
    text = ""
    for bookmark in server.bookmarks.all():
        ossi = bookmark.transition.context_before().ossi
        if ossi is None:
            continue
        location = ossi.location()
        if location is None:
            continue
        if location.binary is None:
            continue
        if location.rva is None:
            continue
        name = location.binary.name
        # WinDbg requires the precise name of the kernel, which is difficult to get.
        # WinDbg seems to always accept "nt" as name for the kernel, so replace that.
        if name == "ntoskrnl":
            name = "nt"
        text += f"bp {name}+{location.rva:#x}\r\n"  # for windows it is safest to have the \r
    if output is None:
        print(text)
    else:
        try:
            with open(output, "w") as f:
                f.write(text)
        except OSError as ose:
            raise ValueError(f"Could not open file {output}: {ose}")


# %% [markdown]
# ### Argument parsing
#
# Argument parsing function for use in the script context.


# %%
def script_main():
    parser = argparse.ArgumentParser(
        description="Convert the bookmarks of a scenario to a WinDbg breakpoints commands.",
        epilog="Requires the Fast Search and the OSSI features replayed.",
    )
    parser.add_argument(
        "--host",
        type=str,
        default="localhost",
        required=False,
        help='Reven host, as a string (default: "localhost")',
    )
    parser.add_argument(
        "-p",
        "--port",
        type=int,
        default="13370",
        required=False,
        help="Reven port, as an int (default: 13370)",
    )
    parser.add_argument(
        "-o",
        "--output-file",
        type=str,
        required=False,
        help="The target file of the script. If absent, the results will be printed on the standard output.",
    )

    args = parser.parse_args()

    try:
        server = reven2.RevenServer(args.host, args.port)
    except RuntimeError:
        raise RuntimeError(f"Could not connect to the server on {args.host}:{args.port}.")

    bk2bp(server, args.output_file)


# %% [markdown]
# ### Parameters
#
# These parameters have to be filled out to use in the notebook context.

# %%
# Server connection
#
host = "localhost"
port = 13370


# Output target
#
# If set to a path, writes the breakpoint commands file there
output_file = None  # display bp commands inline in the Jupyter Notebook
# output_file = "breakpoints.txt"  # write bp commands to a file named "breakpoints.txt" in the current directory

# %% [markdown]
# ### Execution cell
#
# This cell executes according to the [parameters](#Parameters) when in notebook context, or according to the
# [parsed arguments](#Argument-parsing) when in script context.
#
# When in notebook context, if the `output` parameter is `None`, then the output will be displayed in the last cell of
# the notebook.

# %%
if __name__ == "__main__":
    if in_notebook():
        try:
            server = reven2.RevenServer(host, port)
        except RuntimeError:
            raise RuntimeError(f"Could not connect to the server on {host}:{port}.")
        bk2bp(server, output_file)
    else:
        script_main()

# %%
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