Re: Feature request: Settings to disable comments and multiple statements in a connection

On 6/7/25 14:56, Adrian Klaver wrote:
> 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)

Oops, missed a quote:

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

Still I don't see how this would work, even if you add another ';' and got:

production=# select username, first_name, last_name from auth_user where
username = 'aklaver'--;' and password = 'password';
production-# ;
username | first_name | last_name
----------+------------+-----------
aklaver | Adrian | Klaver

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

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com