From 5be5ffbf4954ccdf06039fb4f8bedd1da5d8d2f0 Mon Sep 17 00:00:00 2001 From: besendorf Date: Thu, 23 Oct 2025 15:09:37 +0200 Subject: [PATCH] add mounts module for androidqf (#710) * add mounts module for androidqf * adds test for mounts module --- src/mvt/android/artifacts/mounts.py | 186 ++++++++++++++++++ src/mvt/android/modules/androidqf/__init__.py | 2 + src/mvt/android/modules/androidqf/mounts.py | 74 +++++++ tests/android_androidqf/test_mounts.py | 97 +++++++++ 4 files changed, 359 insertions(+) create mode 100644 src/mvt/android/artifacts/mounts.py create mode 100644 src/mvt/android/modules/androidqf/mounts.py create mode 100644 tests/android_androidqf/test_mounts.py diff --git a/src/mvt/android/artifacts/mounts.py b/src/mvt/android/artifacts/mounts.py new file mode 100644 index 0000000..6e7b0b6 --- /dev/null +++ b/src/mvt/android/artifacts/mounts.py @@ -0,0 +1,186 @@ +# Mobile Verification Toolkit (MVT) +# Copyright (c) 2021-2023 The MVT Authors. +# Use of this software is governed by the MVT License 1.1 that can be found at +# https://license.mvt.re/1.1/ + +from typing import Any + +from .artifact import AndroidArtifact + +SUSPICIOUS_MOUNT_POINTS = [ + "/system", + "/vendor", + "/product", + "/system_ext", +] + +SUSPICIOUS_OPTIONS = [ + "rw", + "remount", + "noatime", + "nodiratime", +] + +ALLOWLIST_NOATIME = [ + "/system_dlkm", + "/system_ext", + "/product", + "/vendor", + "/vendor_dlkm", +] + + +class Mounts(AndroidArtifact): + """ + This artifact parses mount information from /proc/mounts or similar mount data. + It can detect potentially suspicious mount configurations that may indicate + a rooted or compromised device. + """ + + def parse(self, entry: str) -> None: + """ + Parse mount information from the provided entry. + + Examples: + /dev/block/bootdevice/by-name/system /system ext4 ro,seclabel,relatime 0 0 + /dev/block/dm-12 on / type ext4 (ro,seclabel,noatime) + """ + self.results: list[dict[str, Any]] = [] + + for line in entry.splitlines(): + line = line.strip() + if not line: + continue + + device = None + mount_point = None + filesystem_type = None + mount_options = "" + + if " on " in line and " type " in line: + try: + # Format: device on mount_point type filesystem_type (options) + device_part, rest = line.split(" on ", 1) + device = device_part.strip() + + # Split by 'type' to get mount_point and filesystem info + mount_part, fs_part = rest.split(" type ", 1) + mount_point = mount_part.strip() + + # Parse filesystem and options + if "(" in fs_part and fs_part.endswith(")"): + # Format: filesystem_type (options) + fs_and_opts = fs_part.strip() + paren_idx = fs_and_opts.find("(") + filesystem_type = fs_and_opts[:paren_idx].strip() + mount_options = fs_and_opts[paren_idx + 1 : -1].strip() + else: + # No options in parentheses, just filesystem type + filesystem_type = fs_part.strip() + mount_options = "" + + # Skip if we don't have essential info + if not device or not mount_point or not filesystem_type: + continue + + # Parse options into list + options_list = ( + [opt.strip() for opt in mount_options.split(",") if opt.strip()] + if mount_options + else [] + ) + + # Check if it's a system partition + is_system_partition = mount_point in SUSPICIOUS_MOUNT_POINTS or any( + mount_point.startswith(sp) for sp in SUSPICIOUS_MOUNT_POINTS + ) + + # Check if it's mounted read-write + is_read_write = "rw" in options_list + + mount_entry = { + "device": device, + "mount_point": mount_point, + "filesystem_type": filesystem_type, + "mount_options": mount_options, + "options_list": options_list, + "is_system_partition": is_system_partition, + "is_read_write": is_read_write, + } + + self.results.append(mount_entry) + + except ValueError: + # If parsing fails, skip this line + continue + else: + # Skip lines that don't match expected format + continue + + def check_indicators(self) -> None: + """ + Check for suspicious mount configurations that may indicate root access + or other security concerns. + """ + system_rw_mounts = [] + suspicious_mounts = [] + + for mount in self.results: + mount_point = mount["mount_point"] + options = mount["options_list"] + + # Check for system partitions mounted as read-write + if mount["is_system_partition"] and mount["is_read_write"]: + system_rw_mounts.append(mount) + if mount_point == "/system": + self.log.warning( + "Root detected /system partition is mounted as read-write (rw). " + ) + else: + self.log.warning( + "System partition %s is mounted as read-write (rw). This may indicate system modifications.", + mount_point, + ) + + # Check for other suspicious mount options + suspicious_opts = [opt for opt in options if opt in SUSPICIOUS_OPTIONS] + if suspicious_opts and mount["is_system_partition"]: + if ( + "noatime" in mount["mount_options"] + and mount["mount_point"] in ALLOWLIST_NOATIME + ): + continue + suspicious_mounts.append(mount) + self.log.warning( + "Suspicious mount options found for %s: %s", + mount_point, + ", ".join(suspicious_opts), + ) + + # Log interesting mount information + if mount_point == "/data" or mount_point.startswith("/sdcard"): + self.log.info( + "Data partition: %s mounted as %s with options: %s", + mount_point, + mount["filesystem_type"], + mount["mount_options"], + ) + + self.log.info("Parsed %d mount entries", len(self.results)) + + # Check indicators if available + if not self.indicators: + return + + for mount in self.results: + # Check if any mount points match indicators + ioc = self.indicators.check_file_path(mount.get("mount_point", "")) + if ioc: + mount["matched_indicator"] = ioc + self.detected.append(mount) + + # Check device paths for indicators + ioc = self.indicators.check_file_path(mount.get("device", "")) + if ioc: + mount["matched_indicator"] = ioc + self.detected.append(mount) diff --git a/src/mvt/android/modules/androidqf/__init__.py b/src/mvt/android/modules/androidqf/__init__.py index cdb0af8..dd68457 100644 --- a/src/mvt/android/modules/androidqf/__init__.py +++ b/src/mvt/android/modules/androidqf/__init__.py @@ -19,6 +19,7 @@ from .processes import Processes from .settings import Settings from .sms import SMS from .files import Files +from .mounts import Mounts ANDROIDQF_MODULES = [ DumpsysActivities, @@ -37,4 +38,5 @@ ANDROIDQF_MODULES = [ SMS, DumpsysPackages, Files, + Mounts, ] diff --git a/src/mvt/android/modules/androidqf/mounts.py b/src/mvt/android/modules/androidqf/mounts.py new file mode 100644 index 0000000..1a5ba5c --- /dev/null +++ b/src/mvt/android/modules/androidqf/mounts.py @@ -0,0 +1,74 @@ +# Mobile Verification Toolkit (MVT) +# Copyright (c) 2021-2023 The MVT Authors. +# Use of this software is governed by the MVT License 1.1 that can be found at +# https://license.mvt.re/1.1/ + +import logging +import json +from typing import Optional + +from mvt.android.artifacts.mounts import Mounts as MountsArtifact + +from .base import AndroidQFModule + + +class Mounts(MountsArtifact, AndroidQFModule): + """This module extracts and analyzes mount information from AndroidQF acquisitions.""" + + def __init__( + self, + file_path: Optional[str] = None, + target_path: Optional[str] = None, + results_path: Optional[str] = None, + module_options: Optional[dict] = None, + log: logging.Logger = logging.getLogger(__name__), + results: Optional[list] = None, + ) -> None: + super().__init__( + file_path=file_path, + target_path=target_path, + results_path=results_path, + module_options=module_options, + log=log, + results=results, + ) + self.results = [] + + def run(self) -> None: + """ + Run the mounts analysis module. + + This module looks for mount information files collected by androidqf + and analyzes them for suspicious configurations, particularly focusing + on detecting root access indicators like /system mounted as read-write. + """ + mount_files = self._get_files_by_pattern("*/mounts.json") + + if not mount_files: + self.log.info("No mount information file found") + return + + self.log.info("Found mount information file: %s", mount_files[0]) + + try: + data = self._get_file_content(mount_files[0]).decode( + "utf-8", errors="replace" + ) + except Exception as exc: + self.log.error("Failed to read mount information file: %s", exc) + return + + # Parse the mount data + try: + json_data = json.loads(data) + + if isinstance(json_data, list): + # AndroidQF format: array of strings like + # "/dev/block/dm-12 on / type ext4 (ro,seclabel,noatime)" + mount_content = "\n".join(json_data) + self.parse(mount_content) + except Exception as exc: + self.log.error("Failed to parse mount information: %s", exc) + return + + self.log.info("Extracted a total of %d mount entries", len(self.results)) diff --git a/tests/android_androidqf/test_mounts.py b/tests/android_androidqf/test_mounts.py new file mode 100644 index 0000000..89e5e17 --- /dev/null +++ b/tests/android_androidqf/test_mounts.py @@ -0,0 +1,97 @@ +# Mobile Verification Toolkit (MVT) +# Copyright (c) 2021-2023 The MVT Authors. +# Use of this software is governed by the MVT License 1.1 that can be found at +# https://license.mvt.re/1.1/ + +import logging +from pathlib import Path + +from mvt.common.module import run_module + +from ..utils import get_android_androidqf, list_files + + +class TestAndroidqfMountsArtifact: + def test_parse_mounts_token_checks(self): + """ + Test the artifact-level `parse` method using tolerant token checks. + + Different parser variants may place mount tokens into different dict + keys (for example `mount_options`, `pass_num`, `dump_freq`, etc.). To + avoid brittle assertions we concatenate each parsed entry's values and + look for expected tokens (device names, mount points, options) somewhere + in the combined representation. + """ + from mvt.android.artifacts.mounts import Mounts as MountsArtifact + + m = MountsArtifact() + + mount_lines = [ + "/dev/block/dm-12 on / type ext4 (ro,seclabel,noatime)", + "/dev/block/by-name/system on /system type ext4 (rw,seclabel,noatime)", + "/dev/block/by-name/data on /data type f2fs (rw,nosuid,nodev,noatime)", + ] + mount_content = "\n".join(mount_lines) + + # Parse the mount lines (artifact-level) + m.parse(mount_content) + + # Basic sanity: parser should return one entry per input line + assert len(m.results) == 3, f"Expected 3 parsed mounts, got: {m.results}" + + # Concatenate each entry's values into a single string so token checks + # are tolerant to which dict keys were used by the parser. + def concat_values(entry): + parts = [] + for v in entry.values(): + try: + parts.append(str(v)) + except Exception: + # Skip values that can't be stringified + continue + return " ".join(parts) + + concatenated = [concat_values(e) for e in m.results] + + # Token expectations (tolerant): + # - Root line should include 'dm-12' and 'noatime' (and typically 'ro') + assert any("dm-12" in s and "noatime" in s for s in concatenated), ( + f"No root-like tokens (dm-12 + noatime) found in parsed results: {concatenated}" + ) + + # - System line should include '/system' or 'by-name/system' and 'rw' + assert any( + (("by-name/system" in s or "/system" in s) and "rw" in s) + for s in concatenated + ), ( + f"No system-like tokens (system + rw) found in parsed results: {concatenated}" + ) + + # - Data line should include '/data' or 'by-name/data' and 'rw' + assert any( + (("by-name/data" in s or "/data" in s) and "rw" in s) for s in concatenated + ), f"No data-like tokens (data + rw) found in parsed results: {concatenated}" + + +class TestAndroidqfMountsModule: + def test_androidqf_module_no_mounts_file(self): + """ + When no `mounts.json` is present in the androidqf dataset, the module + should not produce results nor detections. + """ + from mvt.android.modules.androidqf.mounts import Mounts + + data_path = get_android_androidqf() + m = Mounts(target_path=data_path, log=logging) + files = list_files(data_path) + parent_path = Path(data_path).absolute().parent.as_posix() + m.from_folder(parent_path, files) + + run_module(m) + + # The provided androidqf test dataset does not include mounts.json, so + # results should remain empty. + assert len(m.results) == 0, ( + f"Expected no results when mounts.json is absent, got: {m.results}" + ) + assert len(m.detected) == 0, f"Expected no detections, got: {m.detected}"