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Message-ID: <bbdb4e11-9743-4862-9a3c-f7cc7f5022d3@aklaver.com>
Date: Sat, 7 Jun 2025 14:56:45 -0700
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Subject: Re: Feature request: Settings to disable comments and multiple
 statements in a connection
To: Glen K <glenk1973@hotmail.com>, Tom Lane <tgl@sss.pgh.pa.us>
Cc: "pgsql-general@lists.postgresql.org" <pgsql-general@lists.postgresql.org>
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 <1079732.1749078352@sss.pgh.pa.us>
 <BN0P223MB01527999F0D58FEB13757986A869A@BN0P223MB0152.NAMP223.PROD.OUTLOOK.COM>
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From: Adrian Klaver <adrian.klaver@aklaver.com>
In-Reply-To: <BN0P223MB01527999F0D58FEB13757986A869A@BN0P223MB0152.NAMP223.PROD.OUTLOOK.COM>
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On 6/7/25 14:18, Glen K wrote:
>>  I don't believe that this would move the needle on SQL-injection
> safety by enough to be worth doing.  An injection attack is normally
> trying to break out of a quoted string, not a comment.
> 
> Yes, SQL injections frequently involve escaping quoted strings, but if 
> you do a search for SQL injection examples, you will find that most of 
> them (I would say 90% or more) also use comments to remove the remainder 
> of the SQL statement from consideration. Here is one example where an 
> attacker specifies "admin'--;" as the username:
> 
> SELECT * FROM members WHERE username = 'admin'--;' AND password = 
> 'password';
> 
> The comment in this example removes the password from inclusion in the 
> statement, allowing the attacker to login as admin without a password.

Really?

select username, first_name, last_name from auth_user where username = 
'aklaver';

  username | first_name | last_name
----------+------------+-----------
  aklaver  | Adrian     | Klaver

  select username, first_name, last_name from auth_user where username = 
'aklaver--;' and password = 'password';

  username | first_name | last_name
----------+------------+-----------
(0 rows)

What authentication system are you using that does not actually verify 
the password and allows entry for a zero return result?


-- 
Adrian Klaver
adrian.klaver@aklaver.com