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Python: fix py/insecure-protocol false positive on ssl.create_default_context() #22028

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Python: fix py/insecure-protocol false positive on ssl.create_default_context() #22028

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7 changes: 5 additions & 2 deletions python/ql/src/Security/CWE-327/Ssl.qll
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Original file line number Diff line number Diff line change
Expand Up @@ -33,9 +33,12 @@ class SslDefaultContextCreation extends ContextCreation {
this = API::moduleImport("ssl").getMember("create_default_context").getACall()
}

// Allowed insecure versions are "TLSv1" and "TLSv1_1"
// Since Python 3.10, `ssl.create_default_context` returns a context whose
// `minimum_version` defaults to `TLSVersion.TLSv1_2`, so TLSv1 and TLSv1_1 are not allowed.
// (Earlier Python versions also allowed TLSv1 and TLSv1_1.)
// see https://docs.python.org/3/library/ssl.html#context-creation
override ProtocolVersion getProtocol() { result in ["TLSv1", "TLSv1_1", "TLSv1_2", "TLSv1_3"] }
// and https://docs.python.org/3/whatsnew/3.10.html#ssl
override ProtocolVersion getProtocol() { result in ["TLSv1_2", "TLSv1_3"] }
}

/** Gets a reference to an `ssl.Context` instance. */
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4 changes: 4 additions & 0 deletions python/ql/src/change-notes/2026-06-20-insecure-protocol-create-default-context.md
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@@ -0,0 +1,4 @@
---
category: minorAnalysis
---
* The `py/insecure-protocol` query no longer reports `ssl.create_default_context` as allowing TLS 1.0 or TLS 1.1. Since Python 3.10, the context returned by `ssl.create_default_context` has its `minimum_version` set to `TLSVersion.TLSv1_2` by default, so these protocol versions are not allowed and the previous alerts were false positives.
2 changes: 0 additions & 2 deletions python/ql/test/query-tests/Security/CWE-327-InsecureProtocol/InsecureProtocol.expected
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Expand Up @@ -41,5 +41,3 @@
| ssl_fluent.py:97:14:97:20 | ControlFlowNode for context | Insecure SSL/TLS protocol version TLSv1_1 allowed by $@. | ssl_fluent.py:65:15:65:46 | ControlFlowNode for Attribute() | call to ssl.SSLContext |
| ssl_fluent.py:146:14:146:20 | ControlFlowNode for context | Insecure SSL/TLS protocol version TLSv1_1 allowed by $@. | ssl_fluent.py:142:15:142:46 | ControlFlowNode for Attribute() | call to ssl.SSLContext |
| ssl_fluent.py:165:14:165:20 | ControlFlowNode for context | Insecure SSL/TLS protocol version SSLv3 allowed by $@. | ssl_fluent.py:161:15:161:65 | ControlFlowNode for Attribute() | call to ssl.create_default_context |
| ssl_fluent.py:165:14:165:20 | ControlFlowNode for context | Insecure SSL/TLS protocol version TLSv1 allowed by $@. | ssl_fluent.py:161:15:161:65 | ControlFlowNode for Attribute() | call to ssl.create_default_context |
| ssl_fluent.py:165:14:165:20 | ControlFlowNode for context | Insecure SSL/TLS protocol version TLSv1_1 allowed by $@. | ssl_fluent.py:161:15:161:65 | ControlFlowNode for Attribute() | call to ssl.create_default_context |
11 changes: 11 additions & 0 deletions python/ql/test/query-tests/Security/CWE-327-InsecureProtocol/ssl_fluent.py
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Expand Up @@ -164,3 +164,14 @@ def test_fluent_explicitly_unsafe():
with socket.create_connection((hostname, 443)) as sock:
with context.wrap_socket(sock, server_hostname=hostname) as ssock: # $ Alert
print(ssock.version())

# Since Python 3.10, `ssl.create_default_context` sets `minimum_version` to
# `TLSVersion.TLSv1_2`, so TLSv1 and TLSv1_1 are not allowed.
# see https://docs.python.org/3/library/ssl.html#context-creation
def test_fluent_default_context_safe():
hostname = 'www.python.org'
context = ssl.create_default_context(ssl.Purpose.SERVER_AUTH)

with socket.create_connection((hostname, 443)) as sock:
with context.wrap_socket(sock, server_hostname=hostname) as ssock: # No alert
print(ssock.version())
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