didericis-claude
451e6fc2fc
Token patterns: HuggingFace (hf_), Databricks (dapi), Slack (xox[baprs]-), npm (npm_), SendGrid (SG.x.y), PyPI (pypi-), HashiCorp Vault (hvs.). Unicode normalization (_normalize_text) applies NFKD + strips combining marks and control chars before pattern matching, defeating fullwidth-char and combining-mark evasion. CRLF injection (scan_crlf_injection) detects %0d%0a in URLs and literal \r\n header-injection patterns; runs unconditionally in scan_outbound regardless of outbound_detectors config.
292 lines
10 KiB
Python
292 lines
10 KiB
Python
"""DLP detectors for the egress proxy (PRD 0053).
|
|
|
|
Pure Python, no mitmproxy dependency. Each detector is a module-level
|
|
function returning `ScanResult | None`.
|
|
|
|
Ships flat into the sidecar bundle image alongside
|
|
`egress_addon_core.py` — both this file and the package source use
|
|
the same try/except import shim pattern.
|
|
"""
|
|
|
|
from __future__ import annotations
|
|
|
|
import base64
|
|
import gzip
|
|
import re
|
|
import typing
|
|
import unicodedata
|
|
from urllib.parse import quote as url_quote
|
|
|
|
try:
|
|
from egress_addon_core import ScanResult # type: ignore[import-not-found]
|
|
except ImportError: # pragma: no cover - host-side path
|
|
from .egress_addon_core import ScanResult
|
|
|
|
|
|
# ---------------------------------------------------------------------------
|
|
# Snippet helpers
|
|
# ---------------------------------------------------------------------------
|
|
|
|
SNIPPET_CONTEXT = 40 # chars of surrounding text to include on each side
|
|
REDACT = "********" # fixed-width replacement for the matched sensitive value
|
|
|
|
|
|
def _snippet(text: str, start: int, end: int) -> str:
|
|
"""Return context around a match with the matched span replaced by REDACT."""
|
|
before = text[max(0, start - SNIPPET_CONTEXT):start].replace("\n", " ").replace("\r", " ")
|
|
after = text[end:end + SNIPPET_CONTEXT].replace("\n", " ").replace("\r", " ")
|
|
return f"{before}{REDACT}{after}"
|
|
|
|
|
|
# ---------------------------------------------------------------------------
|
|
# Unicode normalization (defeats confusable-char and combining-mark evasion)
|
|
# ---------------------------------------------------------------------------
|
|
|
|
def _normalize_text(text: str) -> str:
|
|
# NFKD separates base characters from combining marks and resolves
|
|
# compatibility equivalents (fullwidth ASCII, ligatures, etc.)
|
|
decomposed = unicodedata.normalize("NFKD", text)
|
|
return "".join(
|
|
ch for ch in decomposed
|
|
# Strip combining marks inserted between chars to break patterns
|
|
if unicodedata.category(ch) != "Mn"
|
|
# Strip control chars; keep common whitespace (\n \r \t)
|
|
and (unicodedata.category(ch) != "Cc" or ch in "\n\r\t")
|
|
)
|
|
|
|
|
|
# ---------------------------------------------------------------------------
|
|
# Token patterns detector
|
|
# ---------------------------------------------------------------------------
|
|
|
|
TOKEN_PATTERNS: tuple[tuple[str, re.Pattern[str]], ...] = (
|
|
("AWS access key", re.compile(r"AKIA[0-9A-Z]{16}")),
|
|
("GitHub token (classic)", re.compile(r"ghp_[A-Za-z0-9_]{36}")),
|
|
("GitHub fine-grained token", re.compile(r"github_pat_[A-Za-z0-9_]{82}")),
|
|
("Anthropic API key", re.compile(r"sk-ant-[A-Za-z0-9\-_]{93}")),
|
|
("OpenAI API key", re.compile(r"sk-[A-Za-z0-9]{48}")),
|
|
("OpenAI project API key", re.compile(r"sk-proj-[A-Za-z0-9_\-]{48,}")),
|
|
("Stripe live key", re.compile(r"sk_live_[A-Za-z0-9]{24}")),
|
|
("Generic Bearer JWT", re.compile(r"Bearer\s+[A-Za-z0-9._\-]{50,}")),
|
|
("HuggingFace token", re.compile(r"hf_[A-Za-z0-9]{34,}")),
|
|
("Databricks token", re.compile(r"dapi[A-Za-z0-9]{32}")),
|
|
("Slack token", re.compile(r"xox[baprs]-[A-Za-z0-9]+-[A-Za-z0-9]+-[A-Za-z0-9]{24,}")),
|
|
("npm token", re.compile(r"npm_[A-Za-z0-9]{36}")),
|
|
("SendGrid API key", re.compile(r"SG\.[A-Za-z0-9_\-]{22}\.[A-Za-z0-9_\-]{43}")),
|
|
("PyPI token", re.compile(r"pypi-[A-Za-z0-9_\-]{80,}")),
|
|
("HashiCorp Vault token", re.compile(r"hvs\.[A-Za-z0-9_\-]{24,}")),
|
|
)
|
|
|
|
|
|
def scan_token_patterns(text: str, *, location: str = "body") -> ScanResult | None:
|
|
normalized = _normalize_text(text)
|
|
for name, pattern in TOKEN_PATTERNS:
|
|
m = pattern.search(normalized)
|
|
if m is not None:
|
|
return ScanResult(
|
|
severity="block",
|
|
reason=f"{name} found in {location}",
|
|
location=location,
|
|
context=_snippet(text, m.start(), m.end()),
|
|
)
|
|
return None
|
|
|
|
|
|
def redact_tokens(
|
|
text: str,
|
|
*,
|
|
env: typing.Mapping[str, str] | None = None,
|
|
) -> str:
|
|
"""Replace token pattern matches and (if env given) provisioned secrets with REDACT."""
|
|
for _, pattern in TOKEN_PATTERNS:
|
|
text = pattern.sub(REDACT, text)
|
|
if env is not None:
|
|
for key, value in env.items():
|
|
if key.startswith("EGRESS_TOKEN_") and value:
|
|
for variant in _encoded_variants(value):
|
|
text = text.replace(variant, REDACT)
|
|
return text
|
|
|
|
|
|
# ---------------------------------------------------------------------------
|
|
# Known secrets detector (Phase 1b)
|
|
# ---------------------------------------------------------------------------
|
|
|
|
def _encoded_variants(secret: str) -> list[str]:
|
|
"""Return the secret plus common encoded variants for exfil detection."""
|
|
seen: set[str] = {secret}
|
|
variants: list[str] = [secret]
|
|
|
|
def _add(v: str) -> None:
|
|
if v not in seen:
|
|
seen.add(v)
|
|
variants.append(v)
|
|
|
|
secret_bytes = secret.encode("utf-8")
|
|
|
|
# Standard base64 — with and without padding
|
|
b64 = base64.b64encode(secret_bytes).decode("ascii")
|
|
_add(b64)
|
|
_add(b64.rstrip("="))
|
|
|
|
# URL-safe base64 (JWT/OAuth use -_ alphabet) — with and without padding
|
|
b64url = base64.urlsafe_b64encode(secret_bytes).decode("ascii")
|
|
_add(b64url)
|
|
_add(b64url.rstrip("="))
|
|
|
|
# URL percent-encoding
|
|
_add(url_quote(secret, safe=""))
|
|
|
|
# Hex — lowercase and uppercase
|
|
_add(secret_bytes.hex())
|
|
_add(secret_bytes.hex().upper())
|
|
|
|
# Base32 (TOTP seeds, some DNS-exfil channels)
|
|
_add(base64.b32encode(secret_bytes).decode("ascii"))
|
|
|
|
# gzip + base64 (deterministic: mtime=0); recognisable by H4sI prefix
|
|
_add(base64.b64encode(gzip.compress(secret_bytes, mtime=0)).decode("ascii"))
|
|
|
|
return variants
|
|
|
|
|
|
def scan_known_secrets(
|
|
text: str,
|
|
*,
|
|
location: str = "body",
|
|
env: typing.Mapping[str, str] | None = None,
|
|
) -> ScanResult | None:
|
|
if env is None:
|
|
return None
|
|
for key, value in env.items():
|
|
if not key.startswith("EGRESS_TOKEN_") or not value:
|
|
continue
|
|
for variant in _encoded_variants(value):
|
|
pos = text.find(variant)
|
|
if pos >= 0:
|
|
return ScanResult(
|
|
severity="block",
|
|
reason=f"provisioned secret from {key} found in {location}",
|
|
location=location,
|
|
context=_snippet(text, pos, pos + len(variant)),
|
|
)
|
|
return None
|
|
|
|
|
|
# ---------------------------------------------------------------------------
|
|
# Naive prompt injection detector (Phase 2)
|
|
# ---------------------------------------------------------------------------
|
|
|
|
DISCLOSURE_PHRASES: tuple[re.Pattern[str], ...] = (
|
|
re.compile(r"(?i)system\s+prompt"),
|
|
re.compile(r"(?i)my\s+instructions\s+are"),
|
|
re.compile(r"(?i)original\s+instructions"),
|
|
re.compile(r"(?i)secret\s+instructions"),
|
|
re.compile(r"(?i)hidden\s+rules"),
|
|
)
|
|
|
|
JAILBREAK_PHRASES: tuple[re.Pattern[str], ...] = (
|
|
re.compile(r"(?i)ignore\s+previous"),
|
|
re.compile(r"(?i)forget\s+everything"),
|
|
re.compile(r"(?i)disregard\s+(?:all\s+)?(?:previous|prior)"),
|
|
re.compile(r"(?i)pretend\s+you\s+are"),
|
|
re.compile(r"(?i)act\s+as\s+(?:if|though)"),
|
|
)
|
|
|
|
|
|
PROXIMITY_CHARS = 500
|
|
|
|
|
|
def _closest_pair(
|
|
a_matches: list[re.Match[str]],
|
|
b_matches: list[re.Match[str]],
|
|
) -> tuple[re.Match[str], re.Match[str]] | None:
|
|
"""Return the pair (a, b) with the smallest character gap, or None."""
|
|
best: tuple[re.Match[str], re.Match[str]] | None = None
|
|
best_gap: int | None = None
|
|
for a in a_matches:
|
|
for b in b_matches:
|
|
gap = max(0, max(a.start(), b.start()) - min(a.end(), b.end()))
|
|
if best_gap is None or gap < best_gap:
|
|
best_gap = gap
|
|
best = (a, b)
|
|
return best
|
|
|
|
|
|
def scan_naive_injection(text: str) -> ScanResult | None:
|
|
location = "response body"
|
|
disclosure_hits = [m for p in DISCLOSURE_PHRASES for m in p.finditer(text)]
|
|
jailbreak_hits = [m for p in JAILBREAK_PHRASES for m in p.finditer(text)]
|
|
|
|
if disclosure_hits and jailbreak_hits:
|
|
pair = _closest_pair(disclosure_hits, jailbreak_hits)
|
|
if pair is not None:
|
|
dist = max(0, max(pair[0].start(), pair[1].start()) - min(pair[0].end(), pair[1].end()))
|
|
if dist <= PROXIMITY_CHARS:
|
|
first = pair[0] if pair[0].start() <= pair[1].start() else pair[1]
|
|
return ScanResult(
|
|
severity="block",
|
|
reason=(
|
|
f"disclosure and jailbreak phrases within "
|
|
f"{dist} chars in {location}"
|
|
),
|
|
location=location,
|
|
context=_snippet(text, first.start(), first.end()),
|
|
)
|
|
|
|
if disclosure_hits:
|
|
m = disclosure_hits[0]
|
|
return ScanResult(
|
|
severity="warn",
|
|
reason=f"prompt disclosure phrase detected in {location}",
|
|
location=location,
|
|
context=_snippet(text, m.start(), m.end()),
|
|
)
|
|
|
|
if jailbreak_hits:
|
|
m = jailbreak_hits[0]
|
|
return ScanResult(
|
|
severity="warn",
|
|
reason=f"jailbreak phrase detected in {location}",
|
|
location=location,
|
|
context=_snippet(text, m.start(), m.end()),
|
|
)
|
|
|
|
return None
|
|
|
|
|
|
# ---------------------------------------------------------------------------
|
|
# CRLF injection detector
|
|
# ---------------------------------------------------------------------------
|
|
|
|
# URL-encoded CRLF is never legitimate in a request URL or header value.
|
|
_CRLF_ENCODED_RE = re.compile(r"%0[dD]%0[aA]", re.ASCII)
|
|
# Literal CRLF followed by a header-name pattern indicates header injection.
|
|
_CRLF_HEADER_INJECT_RE = re.compile(r"\r\n[A-Za-z][A-Za-z0-9\-]+\s*:", re.ASCII)
|
|
|
|
|
|
def scan_crlf_injection(text: str) -> ScanResult | None:
|
|
if _CRLF_ENCODED_RE.search(text):
|
|
return ScanResult(
|
|
severity="block",
|
|
reason="URL-encoded CRLF (%0d%0a) in outbound request",
|
|
)
|
|
if _CRLF_HEADER_INJECT_RE.search(text):
|
|
return ScanResult(
|
|
severity="block",
|
|
reason="CRLF header injection pattern in outbound request",
|
|
)
|
|
return None
|
|
|
|
|
|
__all__ = [
|
|
"REDACT",
|
|
"SNIPPET_CONTEXT",
|
|
"TOKEN_PATTERNS",
|
|
"redact_tokens",
|
|
"scan_crlf_injection",
|
|
"scan_known_secrets",
|
|
"scan_naive_injection",
|
|
"scan_token_patterns",
|
|
]
|