16f6c0aecf
Inline adoc files when they are included exactly once. Also fix language tags because this inlining gives us better information on what language the code is written in.
54 lines
1.4 KiB
Plaintext
54 lines
1.4 KiB
Plaintext
== How to fix it in Python SQLite
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=== Code examples
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The following code is an example of an overly simple data retrieval function.
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It is vulnerable to SQL injection because user-controlled data is inserted
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directly into a query string: The application assumes that incoming data
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always has a specific range of characters and ignores that some characters may
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change the query logic to a malicious one.
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In this particular case, the query can be exploited with the following string:
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----
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' OR '1'='1
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----
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Using the UNION clause, an attacker would also be able to perform queries against
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other tables and combine the returned data within the same query result.
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==== Noncompliant code example
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[source,python,diff-id=1,diff-type=noncompliant]
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----
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from flask import request
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@app.route('/example')
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def get_users():
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user = request.args["user"]
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sql = """SELECT user FROM users WHERE user = \'%s\'"""
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conn = sqlite3.connect('example')
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conn.cursor().execute(sql % (user)) # Noncompliant
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----
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==== Compliant solution
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[source,python,diff-id=1,diff-type=compliant]
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----
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from flask import request
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@app.route('/example')
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def get_users():
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user = request.args["user"]
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sql = """SELECT user FROM users WHERE user = (?)"""
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value = (user,)
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conn = sqlite3.connect('example')
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conn.cursor().execute(sql, value)
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----
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=== How does this work?
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include::../../common/fix/prepared-statements.adoc[]
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