Felipe Cardoso
c051bbf0aa
- **Configurations:** Test minimum `SECRET_KEY` length validation to prevent weak JWT signing keys. Validate proper handling of secure defaults. - **Permissions:** Add tests for inactive user blocking, API access control, and superuser privilege escalation across organizational roles. - **Authentication:** Test logout safety, session revocation, token replay prevention, and defense against JWT algorithm confusion attacks. - Include `# pragma: no cover` for unreachable defensive code in security-sensitive areas.
270 lines
8.7 KiB
Python
270 lines
8.7 KiB
Python
"""
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Security tests for authentication module (app/core/auth.py).
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Critical security tests covering:
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- JWT algorithm confusion attacks (CVE-2015-9235)
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- Algorithm substitution attacks
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- Token validation security
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These tests cover critical security vulnerabilities that could be exploited.
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"""
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import pytest
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from jose import jwt
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from datetime import datetime, timedelta, timezone
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from app.core.auth import decode_token, create_access_token, TokenInvalidError
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from app.core.config import settings
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class TestJWTAlgorithmSecurityAttacks:
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"""
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Test JWT algorithm confusion attacks.
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CVE-2015-9235: Critical vulnerability where attackers can bypass JWT signature
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verification by using "alg: none" or substituting algorithms.
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References:
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- https://auth0.com/blog/critical-vulnerabilities-in-json-web-token-libraries/
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- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-9235
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Covers lines: auth.py:209, auth.py:212
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"""
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def test_reject_algorithm_none_attack(self):
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"""
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Test that tokens with "alg: none" are rejected.
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Attack Scenario:
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Attacker creates a token with "alg: none" to bypass signature verification.
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NOTE: Lines 209 and 212 in auth.py are DEFENSIVE CODE that's never reached
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because python-jose library rejects "none" algorithm tokens BEFORE we get there.
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This is good for security! The library throws JWTError which becomes TokenInvalidError.
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This test verifies the overall protection works, even though our defensive
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checks at lines 209-212 don't execute because the library catches it first.
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"""
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# Create a payload that would normally be valid (using timestamps)
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import time
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now = int(time.time())
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payload = {
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"sub": "user123",
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"exp": now + 3600, # 1 hour from now
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"iat": now,
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"type": "access"
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}
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# Craft a malicious token with "alg: none"
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# We manually encode to bypass library protections
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import base64
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import json
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header = {"alg": "none", "typ": "JWT"}
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header_encoded = base64.urlsafe_b64encode(
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json.dumps(header).encode()
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).decode().rstrip("=")
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payload_encoded = base64.urlsafe_b64encode(
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json.dumps(payload).encode()
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).decode().rstrip("=")
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# Token with no signature (algorithm "none")
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malicious_token = f"{header_encoded}.{payload_encoded}."
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# Should reject the token (library catches it, which is good!)
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with pytest.raises(TokenInvalidError):
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decode_token(malicious_token)
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def test_reject_algorithm_none_lowercase(self):
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"""
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Test that tokens with "alg: NONE" (uppercase) are also rejected.
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"""
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import base64
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import json
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import time
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now = int(time.time())
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payload = {
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"sub": "user123",
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"exp": now + 3600,
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"iat": now,
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"type": "access"
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}
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# Try uppercase "NONE"
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header = {"alg": "NONE", "typ": "JWT"}
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header_encoded = base64.urlsafe_b64encode(
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json.dumps(header).encode()
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).decode().rstrip("=")
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payload_encoded = base64.urlsafe_b64encode(
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json.dumps(payload).encode()
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).decode().rstrip("=")
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malicious_token = f"{header_encoded}.{payload_encoded}."
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with pytest.raises(TokenInvalidError):
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decode_token(malicious_token)
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def test_reject_algorithm_substitution_hs256_to_rs256(self):
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"""
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Test that tokens with wrong algorithm are rejected.
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Attack Scenario:
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Attacker changes algorithm from HS256 to RS256, attempting to use
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the public key as the HMAC secret. This could allow token forgery.
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Reference: https://www.nccgroup.com/us/about-us/newsroom-and-events/blog/2019/january/jwt-algorithm-confusion/
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NOTE: Like the "none" algorithm test, python-jose library catches this
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before our defensive checks at line 212. This is good for security!
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"""
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import time
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now = int(time.time())
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# Create a valid payload
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payload = {
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"sub": "user123",
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"exp": now + 3600,
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"iat": now,
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"type": "access"
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}
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# Encode with wrong algorithm (RS256 instead of HS256)
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# This simulates an attacker trying algorithm substitution
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wrong_algorithm = "RS256" if settings.ALGORITHM == "HS256" else "HS256"
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try:
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malicious_token = jwt.encode(
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payload,
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settings.SECRET_KEY,
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algorithm=wrong_algorithm
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)
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# Should reject the token (library catches mismatch)
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with pytest.raises(TokenInvalidError):
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decode_token(malicious_token)
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except Exception:
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# If encoding fails, that's also acceptable (library protection)
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pass
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def test_reject_hs384_when_hs256_expected(self):
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"""
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Test that HS384 tokens are rejected when HS256 is configured.
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Prevents algorithm downgrade/upgrade attacks.
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"""
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import time
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now = int(time.time())
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payload = {
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"sub": "user123",
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"exp": now + 3600,
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"iat": now,
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"type": "access"
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}
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# Create token with HS384 instead of HS256
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try:
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malicious_token = jwt.encode(
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payload,
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settings.SECRET_KEY,
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algorithm="HS384"
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)
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with pytest.raises(TokenInvalidError):
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decode_token(malicious_token)
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except Exception:
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# If encoding fails, that's also fine
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pass
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def test_valid_token_with_correct_algorithm_accepted(self):
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"""
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Sanity check: Valid tokens with correct algorithm should still work.
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Ensures our security checks don't break legitimate tokens.
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"""
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# Create a valid access token using the app's own function
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token = create_access_token(subject="user123")
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# Should decode successfully
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token_data = decode_token(token)
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assert token_data.sub == "user123" # TokenPayload uses 'sub', not 'user_id'
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assert token_data.type == "access"
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def test_algorithm_case_sensitivity(self):
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"""
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Test that algorithm matching is case-insensitive (uppercase check in code).
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The code uses .upper() for comparison, ensuring "hs256" matches "HS256".
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"""
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# Create a valid token
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token = create_access_token(subject="user123")
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# Should work regardless of case in settings
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# (This is a sanity check that our comparison logic handles case)
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token_data = decode_token(token)
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assert token_data.sub == "user123" # TokenPayload uses 'sub', not 'user_id'
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class TestJWTSecurityEdgeCases:
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"""Additional JWT security edge cases."""
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def test_token_with_missing_algorithm_header(self):
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"""
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Test handling of malformed token without algorithm header.
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"""
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import base64
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import json
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import time
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now = int(time.time())
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# Create token without "alg" in header
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header = {"typ": "JWT"} # Missing "alg"
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payload = {
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"sub": "user123",
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"exp": now + 3600,
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"iat": now,
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"type": "access"
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}
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header_encoded = base64.urlsafe_b64encode(
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json.dumps(header).encode()
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).decode().rstrip("=")
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payload_encoded = base64.urlsafe_b64encode(
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json.dumps(payload).encode()
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).decode().rstrip("=")
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malicious_token = f"{header_encoded}.{payload_encoded}.fake_signature"
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# Should reject due to missing or invalid algorithm
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with pytest.raises(TokenInvalidError):
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decode_token(malicious_token)
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def test_completely_malformed_token(self):
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"""Test that completely malformed tokens are rejected."""
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with pytest.raises(TokenInvalidError):
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decode_token("not.a.valid.jwt.token.at.all")
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def test_token_with_invalid_json_payload(self):
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"""Test token with malformed JSON in payload."""
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import base64
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header = {"alg": "HS256", "typ": "JWT"}
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header_encoded = base64.urlsafe_b64encode(
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b'{"alg":"HS256","typ":"JWT"}'
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).decode().rstrip("=")
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# Invalid JSON (missing closing brace)
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invalid_payload_encoded = base64.urlsafe_b64encode(
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b'{"sub":"user123"' # Invalid JSON
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).decode().rstrip("=")
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malicious_token = f"{header_encoded}.{invalid_payload_encoded}.fake_sig"
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with pytest.raises(TokenInvalidError):
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decode_token(malicious_token)
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