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Difference between revisions of "SQL injection/Blind/Extraction"

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== Bitwise Extraction ==  
+
== Blind extraction ==  
  
'''There are multiple types of bitwise extraction attacks:'''
+
'''There are multiple types of blind data extraction attacks:'''
 
* Timing based
 
* Timing based
 
* Pre-computation based
 
* Pre-computation based
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'''The only three things that all of these methods have in common is:'''
 
'''The only three things that all of these methods have in common is:'''
 
* <u>These attacks</u> are all limited in some fashion because of local environment and latency or remote environment and dataset.
 
* <u>These attacks</u> are all limited in some fashion because of local environment and latency or remote environment and dataset.
* <u>The target environment</u> must not filter or otherwise restrict the use of commas (''','''); [[#Testing_with_Regular_Expression_Operators_.28REGEXP.2C_.7E.2C_and_RLIKE.29|regular expressions]] will not work here because injected queries are <i>selecting</i> rather than <i>comparing</i> the value of a single [[byte]].
 
 
* <u>You</u> must not be afraid of programming.
 
* <u>You</u> must not be afraid of programming.
  
===Timing-based bitwise extraction===
+
===Timing-based extraction===
 
{{warning|<i>If not on a '''LAN''' when this technique is utilized, buggy and unpredictable results '''will''' be attained.</i>}}
 
{{warning|<i>If not on a '''LAN''' when this technique is utilized, buggy and unpredictable results '''will''' be attained.</i>}}
 
This testing is ideal when''':
 
This testing is ideal when''':

Revision as of 17:07, 19 November 2012

Blind extraction

There are multiple types of blind data extraction attacks:

  • Timing based
  • Pre-computation based

The only three things that all of these methods have in common is:

  • These attacks are all limited in some fashion because of local environment and latency or remote environment and dataset.
  • You must not be afraid of programming.

Timing-based extraction

RPU0j.png If not on a LAN when this technique is utilized, buggy and unpredictable results will be attained.

This testing is ideal when:

  • It is taking place on a relatively low latency network
  • There is access to a consistent latency and the remote page has a consistent load time (may not vary by more than 0.5 seconds)

Single byte exfiltration takes less queries to perform the same results, and leaves a smaller log footprint.

  • A timer will need to be used to see how long it takes the remote server to serve the page.

Examples of timing-based single-byte exfiltration:

  • Exfiltrating the first character of the database name in a single request:
 
  AND sleep(ascii(SUBSTRING(@@DATABASE,1,1)))                  -- MySQL
  AND pg_sleep(ascii(SUBSTRING(current_database,1,1))) IS NULL -- PostgreSQL
 
By timing these (in seconds) the integer value of the ascii code of the first character of the database will be attained.