adding gibberish detector

.pre-commit-config.yaml

@@ -29,8 +29,10 @@ repos:
     rev: v1.4.4
     hooks:
     -   id: autopep8
--   repo: https://github.com/Yelp/detect-secrets
-    rev: v1.0.1
+-   repo: local
     hooks:
     -   id: detect-secrets
+        name: Detect secrets
+        language: python
+        entry: detect-secrets-hook
         args: ['--baseline', '.secrets.baseline']

.secrets.baseline

@@ -1,5 +1,5 @@
 {
-  "version": "1.0.1",
+  "version": "1.0.3",
   "plugins_used": [
     {
       "name": "ArtifactoryDetector"
@@ -74,6 +74,10 @@
       "path": "detect_secrets.filters.common.is_ignored_due_to_verification_policies",
       "min_level": 2
     },
+    {
+      "path": "detect_secrets.filters.gibberish.should_exclude_secret",
+      "limit": 3.7
+    },
     {
       "path": "detect_secrets.filters.heuristic.is_indirect_reference"
     },
@@ -100,38 +104,6 @@
     }
   ],
   "results": {
-    "README.md": [
-      {
-        "type": "Secret Keyword",
-        "filename": "README.md",
-        "hashed_secret": "25d176b9bc8c2a063e8319e044bd127b49a15755",
-        "is_verified": false,
-        "line_number": 483
-      }
-    ],
-    "detect_secrets/plugins/keyword.py": [
-      {
-        "type": "Secret Keyword",
-        "filename": "detect_secrets/plugins/keyword.py",
-        "hashed_secret": "0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33",
-        "is_verified": false,
-        "line_number": 178
-      },
-      {
-        "type": "Secret Keyword",
-        "filename": "detect_secrets/plugins/keyword.py",
-        "hashed_secret": "62cdb7020ff920e5aa642c3d4066950dd1f01f4d",
-        "is_verified": false,
-        "line_number": 189
-      },
-      {
-        "type": "Secret Keyword",
-        "filename": "detect_secrets/plugins/keyword.py",
-        "hashed_secret": "1af17e73721dbe0c40011b82ed4bb1a7dbe3ce29",
-        "is_verified": false,
-        "line_number": 223
-      }
-    ],
     "detect_secrets/plugins/private_key.py": [
       {
         "type": "Private Key",
@@ -230,30 +202,14 @@
         "is_verified": false,
         "line_number": 53
       },
-      {
-        "type": "Secret Keyword",
-        "filename": "docs/design.md",
-        "hashed_secret": "fc782b0875be9e076d80f5da1430d6ea501c87e5",
-        "is_verified": false,
-        "line_number": 54
-      },
       {
         "type": "Base64 High Entropy String",
         "filename": "docs/design.md",
         "hashed_secret": "513e0a36963ae1e8431c041b744679ee578b7c44",
         "is_verified": false,
         "line_number": 200
       }
-    ],
-    "docs/filters.md": [
-      {
-        "type": "Secret Keyword",
-        "filename": "docs/filters.md",
-        "hashed_secret": "4566d0493d8a9b7a811728e852ed5df95fa70dd2",
-        "is_verified": false,
-        "line_number": 55
-      }
     ]
   },
-  "generated_at": "2021-02-25T19:11:59Z"
+  "generated_at": "2021-03-04T15:43:23Z"
 }

MANIFEST.in

@@ -0,0 +1 @@
+include detect_secrets/filters/gibberish/rfc.model

README.md

@@ -356,9 +356,6 @@ filter options:
                         If filenames match this regex, it will be ignored.
   --exclude-secrets EXCLUDE_SECRETS
                         If secrets match this regex, it will be ignored.
-  --word-list WORD_LIST_FILE
-                        Text file with a list of words, if a secret contains a
-                        word in the list we ignore it.
   -f FILTER, --filter FILTER
                         Specify path to custom filter. May be a python module
                         path (e.g.
@@ -513,17 +510,6 @@ Or you can specify multiple regex rules as such:
 $ detect-secrets scan --exclude-secrets 'fakesecret' --exclude-secrets '\${.*})'
 ```
 
-#### --word-list
-
-If you know there are certain fake password values that you want to ignore, you can also use
-this option:
-
-```bash
-$ cat wordlist.txt
-not-a-real-secret
-$ detect-secrets scan --word-list wordlist.txt
-```
-
 #### Inline Allowlisting
 
 Sometimes, you want to apply an exclusion to a specific line, rather than globally excluding it.
@@ -556,6 +542,57 @@ $ detect-secrets scan --only-allowlisted
 Want to write more custom logic to filter out false positives? Check out how to do this in
 our [filters documentation](docs/filters.md#Using-Your-Own-Filters).
 
+## Extensions
+
+### wordlist
+
+The `--exclude-secrets` flag allows you to specify regex rules to exclude secret values. However,
+if you want to specify a large list of words instead, you can use the `--word-list` flag.
+
+To use this feature, be sure to install the `pyahocorasick` package, or simply use:
+
+```bash
+$ pip install detect-secrets[word_list]
+```
+
+Then, you can use it as such:
+
+```bash
+$ cat wordlist.txt
+not-a-real-secret
+$ cat sample.ini
+password = not-a-real-secret
+
+# Will show results
+$ detect-secrets scan sample.ini
+
+# No results found
+$ detect-secrets scan --word-list wordlist.txt
+```
+
+### Gibberish Detector
+
+The Gibberish Detector is a simple ML model, that attempts to determine whether a secret value
+is actually gibberish, with the assumption that **real** secret values are not word-like.
+
+To use this feature, be sure to install the `gibberish-detector` package, or use:
+
+```bash
+$ pip install detect-secrets[gibberish]
+```
+
+Check out the [gibberish-detector](https://github.com/domanchi/gibberish-detector) package for
+more information on how to train the model. A pre-trained model (seeded by processing RFCs) will
+be included for easy use.
+
+You can also specify your own model as such:
+
+```bash
+$ detect-secrets scan --gibberish-model custom.model
+```
+
+This is not a default plugin, given that this will ignore secrets such as `password`.
+
 ## Caveats
 
 This is not meant to be a sure-fire solution to prevent secrets from entering the codebase. Only

detect_secrets/core/baseline.py

@@ -90,6 +90,9 @@ def save_to_file(
         If you're trying to decide the difference, ask yourself whether there are any changes
         that does not directly impact the results of the scan.
     """
+    # TODO: I wonder whether this should add the `detect_secrets.filters.common.is_baseline_file`
+    # filter, since we know the filename already. However, one could argue that it would cause
+    # this function to "do more than one thing".
     output = secrets
     if isinstance(secrets, SecretsCollection):
         output = format_for_output(secrets)

detect_secrets/core/usage/filters.py

@@ -65,6 +65,19 @@ def add_filter_options(parent: argparse.ArgumentParser) -> None:
             dest='word_list_file',
         )
 
+    if filters.gibberish.is_feature_enabled():
+        parser.add_argument(
+            '--gibberish-model',
+            type=valid_path,
+            help='Path to model trained with gibberish-detector.',
+            dest='gibberish_model_file',
+        )
+        parser.add_argument(
+            '--gibberish-limit',
+            type=float,
+            help='Threshold to determine whether a string is gibberish.',
+        )
+
     _add_custom_filters(parser)
     _add_disable_flag(parser)
 
@@ -145,6 +158,16 @@ def parse_args(args: argparse.Namespace) -> None:
     ):
         filters.wordlist.initialize(args.word_list_file)
 
+    if filters.gibberish.is_feature_enabled():
+        kwargs = {}
+        if args.gibberish_model_file:
+            kwargs['model_path'] = args.gibberish_model_file
+
+        if args.gibberish_limit:
+            kwargs['limit'] = args.gibberish_limit
+
+        filters.gibberish.initialize(**kwargs)
+
     if not args.no_verify:
         get_settings().filters[
             'detect_secrets.filters.common.is_ignored_due_to_verification_policies'

detect_secrets/filters/__init__.py

@@ -1,4 +1,5 @@
 from . import allowlist     # noqa: F401
+from . import gibberish     # noqa: F401
 from . import heuristic     # noqa: F401
 from . import regex         # noqa: F401
 from . import wordlist      # noqa: F401

detect_secrets/filters/gibberish/__init__.py

@@ -0,0 +1,93 @@
+import os
+import string
+from functools import lru_cache
+from typing import Any
+from typing import Optional
+
+from ...core.plugins import Plugin
+from ...plugins.private_key import PrivateKeyDetector
+from ...settings import get_settings
+from ..util import compute_file_hash
+
+
+Model = Any
+
+
+def is_feature_enabled() -> bool:
+    try:
+        get_model()
+        return True
+    except ImportError:
+        return False
+
+
+def initialize(model_path: Optional[str] = None, limit: float = 3.7) -> None:
+    """
+    :param limit: this limit was obtained through trial and error. Check out
+        the original pull request for rationale.
+
+    :raises: ValueError
+    """
+    path = model_path
+    if not path:
+        path = os.path.join(__path__[0], 'rfc.model')
+
+    model = get_model()
+
+    from gibberish_detector import serializer
+    from gibberish_detector.exceptions import ParsingError
+    with open(path) as f:
+        try:
+            model.update(serializer.deserialize(f.read()))
+        except ParsingError:
+            raise ValueError('Invalid model.')
+
+    config = {
+        'limit': limit,
+    }
+    if model_path:
+        config['model'] = model_path
+        config['file_hash'] = compute_file_hash(model_path)
+
+    path = f'{__name__}.should_exclude_secret'
+    get_settings().filters[path] = config
+
+
+def should_exclude_secret(secret: str, plugin: Optional[Plugin] = None) -> bool:
+    """
+    :param plugin: optional, for easier testing. The dependency injection system
+        will populate its proper value on complete runs.
+    """
+    # Private keys are actual words, so they will be a false negative.
+    if isinstance(plugin, PrivateKeyDetector):
+        return False
+
+    # Through real-life experimentation, we discovered that the gibberish detector
+    # works best with non-hex strings, since hex strings have a too limited charset
+    # to fit our trained models. As such, we cannot make a deterministic decision
+    # in such cases.
+    if not (set(secret) - set(string.hexdigits + '-')):
+        return False
+
+    if not get_model().data or not get_model().charset:
+        raise AssertionError('Attempting to use uninitialized gibberish model.')
+
+    from gibberish_detector.detector import Detector
+    detector = Detector(
+        model=get_model(),
+        threshold=get_settings().filters[f'{__name__}.should_exclude_secret']['limit'],
+    )
+
+    # TODO: secret.lower() is only used currently, since the default model is only
+    # trained with lower case letters. However, in the future, if people want to train
+    # a model that is case-sensitive, we can figure out how to change this.
+    # Unfortunately, it's not straight-forward to just remove the `.lower()` function call,
+    # since if the string is *not* lowered (and the model expects it to be), the results
+    # will be quite different.
+    return not detector.is_gibberish(secret.lower())
+
+
+@lru_cache(maxsize=1)
+def get_model() -> 'Model':
+    from gibberish_detector.model import Model
+    return Model(charset='')

detect_secrets/filters/gibberish/rfc.model

@@ -0,0 +1 @@
+{"charset": "abcdefghijklmnopqrstuvwxyz", "ngram_size": 2, "counts": {"a": {"a": 118635, "b": 630875, "c": 1501150, "d": 938413, "e": 64942, "f": 203534, "g": 892717, "h": 50302, "i": 629589, "j": 16393, "k": 122527, "l": 2134199, "m": 865412, "n": 3466183, "o": 39385, "p": 708687, "q": 15378, "r": 1990681, "s": 1639856, "t": 4062626, "u": 390482, "v": 290066, "w": 65833, "x": 148257, "y": 497074, "z": 9679}, "b": {"a": 299747, "b": 38842, "c": 66484, "d": 26575, "e": 1340130, "f": 29026, "g": 32212, "h": 8693, "i": 355357, "j": 188222, "k": 6350, "l": 528022, "m": 42838, "n": 36585, "o": 271797, "p": 20216, "q": 1650, "r": 143544, "s": 134924, "t": 55332, "u": 282480, "v": 8513, "w": 9195, "x": 4962, "y": 350774, "z": 1991}, "c": {"a": 1583493, "b": 55072, "c": 366166, "d": 99397, "e": 1680049, "f": 61790, "g": 22751, "h": 1138161, "i": 647914, "j": 23415, "k": 608337, "l": 409128, "m": 129894, "n": 63692, "o": 2266996, "p": 202574, "q": 8192, "r": 525914, "s": 234381, "t": 1400393, "u": 582740, "v": 25213, "w": 27222, "x": 12164, "y": 94929, "z": 3613}, "d": {"a": 1102196, "b": 395535, "c": 205472, "d": 521902, "e": 2349496, "f": 230444, "g": 90095, "h": 107584, "i": 1575337, "j": 30840, "k": 23781, "l": 151769, "m": 188851, "n": 183549, "o": 773165, "p": 252828, "q": 10114, "r": 490139, "s": 679426, "t": 677199, "u": 321170, "v": 101547, "w": 168753, "x": 13779, "y": 59907, "z": 4936}, "e": {"a": 1743853, "b": 293141, "c": 2504452, "d": 3070491, "e": 835273, "f": 950803, "g": 431308, "h": 176469, "i": 1177449, "j": 38230, "k": 70232, "l": 1227191, "m": 1322498, "n": 4007948, "o": 705920, "p": 939044, "q": 450185, "r": 5234236, "s": 4637943, "t": 2734401, "u": 284887, "v": 537744, "w": 395249, "x": 721758, "y": 247129, "z": 15923}, "f": {"a": 482902, "b": 46301, "c": 776635, "d": 74453, "e": 459377, "f": 324747, "g": 15818, "h": 24876, "i": 1326013, "j": 5135, "k": 7786, "l": 154253, "m": 68036, "n": 47090, "o": 1525315, "p": 71256, "q": 7352, "r": 399118, "s": 158690, "t": 743932, "u": 192428, "v": 25544, "w": 23974, "x": 11395, "y": 80258, "z": 5178}, "g": {"a": 374124, "b": 43000, "c": 75143, "d": 54891, "e": 1210541, "f": 61951, "g": 89766, "h": 265348, "i": 434656, "j": 9650, "k": 8369, "l": 111072, "m": 141157, "n": 262172, "o": 233776, "p": 126045, "q": 3985, "r": 368752, "s": 199803, "t": 394592, "u": 242465, "v": 16518, "w": 40581, "x": 7464, "y": 46646, "z": 4033}, "h": {"a": 1557099, "b": 48781, "c": 89817, "d": 47268, "e": 4944439, "f": 32193, "g": 12079, "h": 20750, "i": 1105135, "j": 3953, "k": 9651, "l": 32170, "m": 125637, "n": 76152, "o": 775525, "p": 47687, "q": 3047, "r": 145761, "s": 83710, "t": 413869, "u": 73213, "v": 16513, "w": 22152, "x": 4223, "y": 37868, "z": 6960}, "i": {"a": 545417, "b": 441765, "c": 1649054, "d": 823145, "e": 1026129, "f": 883435, "g": 624619, "h": 16297, "i": 47452, "j": 11907, "k": 56496, "l": 788318, "m": 672818, "n": 5188085, "o": 2696322, "p": 641038, "q": 31721, "r": 507827, "s": 2474217, "t": 2145858, "u": 27798, "v": 521907, "w": 8937, "x": 103556, "y": 3155, "z": 178043}, "j": {"a": 65309, "b": 5150, "c": 4630, "d": 3609, "e": 207116, "f": 2967, "g": 2140, "h": 3674, "i": 12565, "j": 1966, "k": 4624, "l": 3278, "m": 6958, "n": 5271, "o": 59640, "p": 7497, "q": 1402, "r": 4799, "s": 15013, "t": 4209, "u": 80334, "v": 2082, "w": 6849, "x": 1481, "y": 1382, "z": 1520}, "k": {"a": 91393, "b": 24180, "c": 35534, "d": 25923, "e": 557437, "f": 32487, "g": 8856, "h": 16581, "i": 173899, "j": 5028, "k": 9027, "l": 40471, "m": 36600, "n": 89335, "o": 53389, "p": 133808, "q": 2485, "r": 28645, "s": 177604, "t": 62173, "u": 27442, "v": 5748, "w": 27477, "x": 2830, "y": 6013, "z": 1805}, "l": {"a": 929370, "b": 103217, "c": 139662, "d": 512423, "e": 1824337, "f": 113308, "g": 78226, "h": 36656, "i": 1450931, "j": 14335, "k": 24164, "l": 983903, "m": 107923, "n": 110976, "o": 905778, "p": 211582, "q": 5416, "r": 114840, "s": 608836, "t": 453915, "u": 460820, "v": 96718, "w": 49654, "x": 6631, "y": 577831, "z": 11631}, "m": {"a": 1635769, "b": 287867, "c": 67799, "d": 50279, "e": 2204807, "f": 38281, "g": 16738, "h": 16864, "i": 672936, "j": 6422, "k": 6652, "l": 90860, "m": 268828, "n": 40050, "o": 527359, "p": 791104, "q": 3281, "r": 47377, "s": 279178, "t": 188486, "u": 454062, "v": 16237, "w": 25264, "x": 6360, "y": 9965, "z": 2639}, "n": {"a": 1538477, "b": 200065, "c": 997362, "d": 2330762, "e": 1952162, "f": 625660, "g": 1940478, "h": 83259, "i": 1015263, "j": 28397, "k": 150610, "l": 214383, "m": 226678, "n": 356573, "o": 1367298, "p": 210677, "q": 9545, "r": 232943, "s": 1723024, "t": 4051859, "u": 306661, "v": 137961, "w": 115060, "x": 18770, "y": 191590, "z": 12659}, "o": {"a": 333611, "b": 507058, "c": 1030631, "d": 621611, "e": 154901, "f": 1509661, "g": 182750, "h": 53343, "i": 324137, "j": 11882, "k": 87654, "l": 804704, "m": 994391, "n": 4575413, "o": 219213, "p": 683677, "q": 4149, "r": 3464564, "s": 641767, "t": 1406855, "u": 1149771, "v": 410511, "w": 561073, "x": 56638, "y": 39476, "z": 8869}, "p": {"a": 1189585, "b": 42076, "c": 124961, "d": 126398, "e": 1242826, "f": 80409, "g": 17643, "h": 137438, "i": 266019, "j": 9649, "k": 35379, "l": 828131, "m": 106979, "n": 68507, "o": 908296, "p": 557551, "q": 4360, "r": 1408275, "s": 295854, "t": 588109, "u": 216552, "v": 162392, "w": 69550, "x": 9971, "y": 42770, "z": 2061}, "q": {"a": 5362, "b": 2396, "c": 3695, "d": 4903, "e": 2437, "f": 2492, "g": 1606, "h": 1937, "i": 6228, "j": 1178, "k": 1502, "l": 2222, "m": 5600, "n": 6138, "o": 16223, "p": 3612, "q": 2178, "r": 4314, "s": 7449, "t": 4457, "u": 523091, "v": 2218, "w": 1957, "x": 1602, "y": 1593, "z": 1147}, "r": {"a": 1884150, "b": 108467, "c": 469520, "d": 619333, "e": 4613547, "f": 928117, "g": 206040, "h": 70002, "i": 1924644, "j": 14216, "k": 336855, "l": 161805, "m": 782008, "n": 396973, "o": 2026650, "p": 279715, "q": 9201, "r": 543892, "s": 939303, "t": 1323019, "u": 276419, "v": 443167, "w": 154662, "x": 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