Re: [sqlmap-users] Optimizing LIMIT 1 UNIONable injections

[Brandon P. <bpe...@gm...>]

> On Aug 15, 2017, at 8:21 PM, Miroslav Stampar <mir...@gm...> wrote:
> 
> Hi.
> 
> sqlmap either does the full dump (FULL UNION case) or one row at a time (PARTIAL UNION case - e.g. single row of result). There is no "let's dump N rows per request" - this is really not possible to do in a simple and generic way as targets tend to cut the results in most exotic ways (e.g. first 1024 characters). Also, concatenation of rows in non-MySQL DBMSes is a challenge at least.

Thanks, you’re right. I’m thinking about this purely from a MySQL perspective.

Thanks for the insight.

> 
> Bye
> 
> On Wed, Aug 16, 2017 at 12:36 AM, Brandon Perry <bpe...@gm... <mailto:bpe...@gm...>> wrote:
> Looking at some later requests, it appears that dumping a row from a table is performed this way (each column is concated together). So it looks like this kind of strategy is just not used consistently when limited to a single row.
> 
> However, it could still chunk multiple rows into a single concat statement (selecting 10 rows per request for instance, instead just one).
> 
> Just thoughts.
> 
> 
> > On Aug 15, 2017, at 4:04 PM, Brandon Perry <bpe...@gm... <mailto:bpe...@gm...>> wrote:
> >
> > Currently, it seems that sqlmap will use a payload such as the following is a UNIONable parameter is found that can only return one row in order for data to be exfil’ed.
> >
> > -16301 UNION ALL SELECT NULL,NULL,(SELECT CONCAT(0x71787a7871,IFNULL(CAST(schema_name AS CHAR),0x20),0x716a706271) FROM INFORMATION_SCHEMA.SCHEMATA LIMIT 4,1),NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL
> >
> > When enumerating databases in an injection like this, sqlmap will make a single request per db name (note the LIMIT clause). This is a bit inefficient. I understand there may be length limitations to query string parameters, but I’m curious why sqlmap wouldn’t use a more efficient payload, such as the following.
> >
> > -16301 UNION ALL SELECT NULL,NULL,CONCAT(0x41414141, (SELECT schema_name FROM INFORMATION_SCHEMA.SCHEMATA LIMIT 4,1), 0x41414141,(SELECT schema_name FROM INFORMATION_SCHEMA.SCHEMATA LIMIT 3,1), 0x41414141,(SELECT schema_name FROM INFORMATION_SCHEMA.SCHEMATA LIMIT 2,1)),NULL,NULL,NULL,NULL,NULL,NULL,NULL,NULL
> >
> > Error-based payloads certainly have length limitations in the data they can get out per request, but is there something preventing sqlmap from implementing a more efficient single-row UNION strategy when exfiltrating data?
> >
> > Let me know if this doesn’t make sense.
> 
> 
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> Miroslav Stampar
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