feat(dlp): fragmentation resistance, entropy detector, broadened known-value scan

- _alnum_projection(): strip non-alphanumeric chars for separator-injection detection
- scan_known_secrets() gains two extra passes per secret after exact-variant matching:
  alnum-projection exact match (catches hyphens/spaces between secret chars) and a
  sliding-window partial-match scan (catches chunked substrings ≥ PARTIAL_MATCH_MIN_LEN)
- scan_known_secrets() accepts sensitive_prefixes param (default ("EGRESS_TOKEN_",))
  so redact_tokens and call-sites can extend the scanned env-var prefix set
- scan_entropy() warn-only detector flagging windows with Shannon entropy ≥ 5.5 bits/char
- "entropy" added to OUTBOUND_DETECTOR_NAMES; scan_outbound opts it in only when
  explicitly listed in dlp.outbound_detectors (never part of the default "all" set)
- scan_outbound reads BOT_BOTTLE_SENSITIVE_PREFIXES from environ to extend
  scan_known_secrets beyond EGRESS_TOKEN_* without schema changes
- Binary bodies decoded via latin-1 fallback (bijective byte↔codepoint) instead
  of utf-8 errors=replace, preserving ASCII secret strings in binary payloads

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
2026-06-25 01:02:34 +00:00
committed by didericis
parent ea6bc5a170
commit 701df6cb2f
5 changed files with 474 additions and 11 deletions
+190 -3
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@@ -1,18 +1,24 @@
"""Unit: DLP detectors (PRD 0053).
"""Unit: DLP detectors (PRD 0053, prd-new).
Tests for token pattern scanning, known secret detection, and
naive prompt injection detection."""
Tests for token pattern scanning, known secret detection, fragmentation-
resistant matching, entropy scoring, and naive prompt injection detection."""
import base64
import gzip
import unittest
from bot_bottle.dlp_detectors import (
ENTROPY_BLOCK_THRESHOLD,
ENTROPY_WINDOW,
PARTIAL_MATCH_MIN_LEN,
REDACT,
_alnum_projection,
_encoded_variants,
_normalize_text,
_shannon_entropy,
redact_tokens,
scan_crlf_injection,
scan_entropy,
scan_known_secrets,
scan_naive_injection,
scan_token_patterns,
@@ -502,6 +508,187 @@ class TestStripCrlf(unittest.TestCase):
from bot_bottle.dlp_detectors import strip_crlf
self.assertEqual("/api/v1/data?q=hello", strip_crlf("/api/v1/data?q=hello"))
class TestAlnumProjection(unittest.TestCase):
def test_alphanumeric_unchanged(self):
self.assertEqual("abc123XYZ", _alnum_projection("abc123XYZ"))
def test_strips_hyphens(self):
self.assertEqual("mysecretvalue", _alnum_projection("my-secret-value"))
def test_strips_spaces(self):
self.assertEqual("mysecretvalue", _alnum_projection("my secret value"))
def test_strips_dots_and_underscores(self):
self.assertEqual("mysecretvalue", _alnum_projection("my.secret_value"))
def test_empty_string(self):
self.assertEqual("", _alnum_projection(""))
def test_all_special_chars(self):
self.assertEqual("", _alnum_projection("!@#$%^&*()"))
class TestFragmentationResistantMatching(unittest.TestCase):
"""scan_known_secrets catches separator-injection and partial-substring evasion."""
# Secrets long enough that their alnum projections are ≥ 8 chars.
SECRET = "supersecrettoken99"
ENV = {"EGRESS_TOKEN_0": SECRET}
def test_exact_match_still_works(self):
result = scan_known_secrets(f"key={self.SECRET}", env=self.ENV)
self.assertIsNotNone(result)
assert result is not None
self.assertEqual("block", result.severity)
def test_separator_injection_blocked(self):
# Hyphens inserted between chars of the secret.
fragmented = "-".join(self.SECRET)
result = scan_known_secrets(f"data={fragmented}", env=self.ENV)
self.assertIsNotNone(result)
assert result is not None
self.assertEqual("block", result.severity)
self.assertIn("separator injection", result.reason)
def test_space_separator_blocked(self):
fragmented = " ".join(self.SECRET)
result = scan_known_secrets(f"body: {fragmented}", env=self.ENV)
self.assertIsNotNone(result)
assert result is not None
self.assertIn("separator injection", result.reason)
def test_partial_substring_blocked(self):
# First PARTIAL_MATCH_MIN_LEN alnum chars of the secret, no separators.
partial = _alnum_projection(self.SECRET)[:PARTIAL_MATCH_MIN_LEN]
result = scan_known_secrets(f"x={partial}&y=other", env=self.ENV)
self.assertIsNotNone(result)
assert result is not None
self.assertEqual("block", result.severity)
self.assertIn("partial match", result.reason)
def test_short_secret_skips_projection(self):
# Secrets shorter than _ALNUM_MIN_LEN in alnum projection are not
# fragmentation-checked (too many false positives).
short_env = {"EGRESS_TOKEN_0": "abc"}
# "a b c" has alnum projection "abc" (3 chars, < 8); should not block.
self.assertIsNone(scan_known_secrets("a b c", env=short_env))
def test_clean_text_not_blocked(self):
self.assertIsNone(scan_known_secrets("nothing to see here", env=self.ENV))
def test_sensitive_prefixes_param_extra_prefix(self):
env = {"MY_CRED_0": self.SECRET, "IGNORED": "other"}
result = scan_known_secrets(
f"key={self.SECRET}",
env=env,
sensitive_prefixes=("MY_CRED_",),
)
self.assertIsNotNone(result)
assert result is not None
self.assertIn("MY_CRED_0", result.reason)
def test_sensitive_prefixes_default_only_egress_token(self):
# A value under a non-EGRESS_TOKEN_ key is ignored with default prefixes.
env = {"MY_CRED_0": self.SECRET}
self.assertIsNone(scan_known_secrets(f"key={self.SECRET}", env=env))
def test_canary_prefix_detected(self):
canary_value = "canary-fake-secret-value-xyz"
env = {"EGRESS_TOKEN_CANARY": canary_value}
result = scan_known_secrets(f"x={canary_value}", env=env)
self.assertIsNotNone(result)
assert result is not None
self.assertIn("EGRESS_TOKEN_CANARY", result.reason)
class TestRedactTokensBroadenedPrefixes(unittest.TestCase):
SECRET = "my-provisioned-secret"
def test_default_redacts_egress_token(self):
env = {"EGRESS_TOKEN_0": self.SECRET}
out = redact_tokens(f"val={self.SECRET}", env=env)
self.assertNotIn(self.SECRET, out)
self.assertIn(REDACT, out)
def test_extra_prefix_redacted(self):
env = {"MY_SECRET_KEY": self.SECRET}
out = redact_tokens(
f"val={self.SECRET}",
env=env,
sensitive_prefixes=("MY_SECRET_",),
)
self.assertNotIn(self.SECRET, out)
self.assertIn(REDACT, out)
def test_non_matching_prefix_not_redacted(self):
env = {"MY_SECRET_KEY": self.SECRET}
out = redact_tokens(f"val={self.SECRET}", env=env)
# Default prefixes only include EGRESS_TOKEN_ → secret not redacted
self.assertIn(self.SECRET, out)
class TestShannonEntropy(unittest.TestCase):
def test_empty_string_zero(self):
self.assertEqual(0.0, _shannon_entropy(""))
def test_single_char_zero(self):
self.assertEqual(0.0, _shannon_entropy("aaaaaa"))
def test_two_equal_chars_one_bit(self):
self.assertAlmostEqual(1.0, _shannon_entropy("abababab"), places=10)
def test_high_entropy_random_like(self):
# Uniform 64-char string over 64 distinct symbols has entropy 6 bits.
import string
alphabet = (string.ascii_letters + string.digits + "+/")[:64]
text = alphabet # each char appears exactly once
self.assertAlmostEqual(6.0, _shannon_entropy(text), places=10)
class TestScanEntropy(unittest.TestCase):
def test_empty_returns_none(self):
self.assertIsNone(scan_entropy(""))
def test_low_entropy_returns_none(self):
# Highly repetitive text has low entropy.
self.assertIsNone(scan_entropy("a" * 200))
def test_high_entropy_warns(self):
# Build a 64-char string with entropy > ENTROPY_BLOCK_THRESHOLD.
# Use all 64 distinct printable chars to maximise entropy (~6 bits).
import string
alphabet = (string.ascii_letters + string.digits + "+/")[:64]
result = scan_entropy(alphabet, threshold=ENTROPY_BLOCK_THRESHOLD)
self.assertIsNotNone(result)
assert result is not None
self.assertEqual("warn", result.severity)
self.assertIn("high-entropy", result.reason)
def test_never_blocks(self):
import string
alphabet = (string.ascii_letters + string.digits + "+/")[:64]
result = scan_entropy(alphabet)
# scan_entropy is warn-only; it must never return severity="block".
if result is not None:
self.assertNotEqual("block", result.severity)
def test_location_in_result(self):
import string
alphabet = (string.ascii_letters + string.digits + "+/")[:64]
result = scan_entropy(alphabet, location="authorization header")
if result is not None:
self.assertIn("authorization header", result.location)
def test_structured_json_no_warn(self):
# Typical JSON has low entropy and should not be flagged.
json_body = '{"status": "ok", "message": "hello world", "count": 42}'
self.assertIsNone(scan_entropy(json_body))
def test_short_text_below_window(self):
# Text shorter than the window: checked as one chunk.
# Use a uniform string to ensure it won't be flagged.
self.assertIsNone(scan_entropy("abcde", threshold=ENTROPY_BLOCK_THRESHOLD))
if __name__ == "__main__":
unittest.main()
+96
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@@ -1273,6 +1273,102 @@ class TestBuildTokenAllowPayload(unittest.TestCase):
result = ScanResult(severity="block", reason="r", matched="x")
payload = build_token_allow_payload("h", "GET", "/", result)
self.assertNotIn("context:", payload)
class TestScanOutboundEnhanced(unittest.TestCase):
"""scan_outbound changes from prd-new: binary decode, entropy detector,
broadened known-value prefixes, fragmentation resistance."""
_ROUTE = Route(host="api.example.com")
_ROUTE_ENTROPY = Route(
host="api.example.com",
outbound_detectors=("entropy",),
)
def test_binary_body_latin1_decode_finds_ascii_secret(self):
# Body contains valid ASCII secret surrounded by non-UTF-8 bytes.
secret = "supersecrettoken99"
env = {"EGRESS_TOKEN_0": secret}
# Wrap the secret in bytes that are invalid UTF-8.
body = b"\x80\x81" + secret.encode("ascii") + b"\xff"
result = scan_outbound(self._ROUTE, body, env)
self.assertIsNotNone(result)
assert result is not None
self.assertEqual("block", result.severity)
def test_binary_body_valid_utf8_decoded_correctly(self):
env = {"EGRESS_TOKEN_0": "mysecret"}
# Valid UTF-8 body — should be decoded as UTF-8, not latin-1.
body = "clean body with mysecret".encode("utf-8")
result = scan_outbound(self._ROUTE, body, env)
self.assertIsNotNone(result)
def test_entropy_detector_off_by_default(self):
import string
# High-entropy content should NOT warn if the route has no entropy detector.
alphabet = (string.ascii_letters + string.digits + "+/")[:64]
result = scan_outbound(self._ROUTE, alphabet, {})
self.assertIsNone(result)
def test_entropy_detector_warns_when_enabled(self):
import string
alphabet = (string.ascii_letters + string.digits + "+/")[:64]
result = scan_outbound(self._ROUTE_ENTROPY, alphabet, {})
self.assertIsNotNone(result)
assert result is not None
self.assertEqual("warn", result.severity)
def test_bot_bottle_sensitive_prefixes_env_var(self):
# When the sidecar env contains BOT_BOTTLE_SENSITIVE_PREFIXES,
# scan_outbound should scan those additional prefixes.
secret = "extra-sensitive-value-abc"
env = {
"MY_CRED_KEY": secret,
"BOT_BOTTLE_SENSITIVE_PREFIXES": "MY_CRED_",
}
result = scan_outbound(self._ROUTE, f"x={secret}", env)
self.assertIsNotNone(result)
assert result is not None
self.assertEqual("block", result.severity)
def test_bot_bottle_sensitive_prefixes_multiple(self):
secret = "my-api-key-value-xyz"
env = {
"ANTHROPIC_API_0": secret,
"BOT_BOTTLE_SENSITIVE_PREFIXES": "ANTHROPIC_API_,OTHER_",
}
result = scan_outbound(self._ROUTE, f"auth={secret}", env)
self.assertIsNotNone(result)
def test_canary_detected_via_egress_token_canary(self):
# The canary (injected as EGRESS_TOKEN_CANARY) is caught by known_secrets.
canary = "canaryvalue12345abcdef"
env = {"EGRESS_TOKEN_CANARY": canary}
result = scan_outbound(self._ROUTE, f"data={canary}", env)
self.assertIsNotNone(result)
assert result is not None
self.assertEqual("block", result.severity)
self.assertIn("EGRESS_TOKEN_CANARY", result.reason)
def test_fragmented_canary_blocked(self):
# Canary with separators injected is still caught.
canary = "supersecretcanary99"
env = {"EGRESS_TOKEN_CANARY": canary}
fragmented = "-".join(canary)
result = scan_outbound(self._ROUTE, f"x={fragmented}", env)
self.assertIsNotNone(result)
class TestOutboundDetectorNames(unittest.TestCase):
def test_entropy_in_outbound_detector_names(self):
from bot_bottle.egress_addon_core import OUTBOUND_DETECTOR_NAMES
self.assertIn("entropy", OUTBOUND_DETECTOR_NAMES)
def test_known_secrets_in_outbound_detector_names(self):
from bot_bottle.egress_addon_core import OUTBOUND_DETECTOR_NAMES
self.assertIn("known_secrets", OUTBOUND_DETECTOR_NAMES)
def test_token_patterns_in_outbound_detector_names(self):
from bot_bottle.egress_addon_core import OUTBOUND_DETECTOR_NAMES
self.assertIn("token_patterns", OUTBOUND_DETECTOR_NAMES)
if __name__ == "__main__":
+2 -1
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@@ -42,6 +42,7 @@ def _plan(
routes_path=routes_path,
routes=("route",),
token_env_map={"EGRESS_TOKEN_0": "HOST_TOKEN"},
canary="",
)
if git:
key_path = stage_dir / "origin-key"
@@ -271,7 +272,7 @@ def _build_plan(stage_dir: Path) -> MacosContainerBottlePlan:
manifest=_MANIFEST,
stage_dir=stage_dir,
git_gate_plan=cast(GitGatePlan, SimpleNamespace(upstreams=())),
egress_plan=cast(EgressPlan, SimpleNamespace()),
egress_plan=cast(EgressPlan, SimpleNamespace(canary="")),
supervise_plan=None,
agent_provision=AgentProvisionPlan(
template="claude",