Another day another hacked website

Yesterday morning, phone rings to notify my of a new sms. Someone could not access his website on some server that I am root/administer.
I tried to ping the server and got 1 reply every 10-15 packets so my initial thought was that the hosting provider had fucked up. I pinged other machines in the “neighborhood”, they replied just fine. So the problem lied in my server. I got console access through IPMI, you know…the ones with the cipher zero bug, and I managed to login. An apache2 process was constantly using 100% of a core and the machine sent gazillion packets towards a certain destination.

Since I wanted to investigate what exactly this process did, I put an iptables entry in my OUTPUT chain to block packets towards that destination. The machine became responsive again, though the apache process still ran at 100%. Since I run my vhosts using apache2 mpm_itk module, I knew through the apache2 PIDs’ username which site had been hacked. I grepped the logs for any POST, but I couldn’t see anything. Unfortunately the logs only go back 2 days (NOT my policy! and a very bad one actually…but anyway).

strace -p PID did not yield anything interesting, just the process trying to create sockets to send packets towards the destination.

socket(PF_NETLINK, SOCK_RAW, 0) = 417
bind(417, {sa_family=AF_NETLINK, pid=0, groups=00000000}, 12) = 0
getsockname(417, {sa_family=AF_NETLINK, pid=11398, groups=00000000}, [12]) = 0
sendto(417, "\24\0\0\0\26\0\1\3\233\323\354Q\0\0\0\0\0\0\0\0", 20, 0, {sa_family=AF_NETLINK, pid=0, groups=00000000}, 12) = 20
recvmsg(417, {msg_name(12)={sa_family=AF_NETLINK, pid=0, groups=00000000}, msg_iov(1)=[{"0\0\0\0\24\0\2\0\233\323\354Q\206,\0\0\2\10\200\376\1\0\0\0\10\0\1\0\177\0\0\1"..., 4096}], msg_controllen=0, msg_flags=0}, 0) = 588
recvmsg(417, {msg_name(12)={sa_family=AF_NETLINK, pid=0, groups=00000000}, msg_iov(1)=[{"@\0\0\0\24\0\2\0\233\323\354Q\206,\0\0\n\200\200\376\1\0\0\0\24\0\1\0\0\0\0\0"..., 4096}], msg_controllen=0, msg_flags=0}, 0) = 128
recvmsg(417, {msg_name(12)={sa_family=AF_NETLINK, pid=0, groups=00000000}, msg_iov(1)=[{"\24\0\0\0\3\0\2\0\233\323\354Q\206,\0\0\0\0\0\0\1\0\0\0\24\0\1\0\0\0\0\0"..., 4096}], msg_controllen=0, msg_flags=0}, 0) = 20
close(417) = 0
fcntl(417, F_GETFL) = 0x2 (flags O_RDWR)
fcntl(417, F_SETFL, O_RDWR|O_NONBLOCK) = 0
connect(417, {sa_family=AF_INET, sin_port=htons(4883), sin_addr=inet_addr("X.Y.Z.W")}, 16) = 0
fcntl(417, F_SETFL, O_RDWR) = 0
sendto(417, "\207\25\312P\322t\0#\317}jf\2(W\374\375\232h\213\220\31\355\277)\320[\255\273\276\221\374"..., 8192, MSG_DONTWAIT, NULL, 0) = -1 EPERM (Operation not permitted)
close(417) = 0

lsof -n -p PID output had hundreds of open log files and a few connections. Grepping out the logs I noticed one that was quite interesting, it went towards another server at port 5555.
apache2 11398 XXXXXXX 416u IPv4 831501972 0t0 TCP A.B.C.D:59210->B.C.D.E:5555 (CLOSE_WAIT)

I run tcpdump there, and of course it was an irc connection. I started capturing everything.

lsof also revealed this:
apache2 11398 XXXXXXX cwd DIR 8,7 4096 2474373 /var/www/vhosts/XXXXXXX/httpdocs/libraries/phpgacl
which I could have have also seen it doing ls /proc/PID/cwd/ …but anyway.

Looking inside that dir I found a file named gacl_db.php. It was base64 encoded. Well actually it was multiple times base64 encoded and obfsuscated by using character substitutions, so I had to de-obfuscate it. It was quite easy using php and some bash scripting.

This is the original base64 encoded/obfuscated file: Original gacl_db.php
This is the final result: Deobfuscated gacl_db.php
(I have removed the irc server details from the deobfuscated file, it’s still there in the original file for whoever wants it though)

It’s just an IRC bot containing a perl reverse shell as well. It has commands to flood other servers, and that’s what my server was doing.

I joined the IRC server and at that time there were more than 90 bots inside. Right now that I’m writing this blog post there are less than 50. Every bot joining the channel outputs a text like this:

[uname!]: FreeBSD a.b.c.d 8.1-RELEASE-p5 FreeBSD 8.1-RELEASE-p5 #10: Fri Sep 30 14:45:56 MSK 2011 root@a.b.c.d:/path/to/to/to/sth pl#27 amd64 (safe: off)
[vuln!]: http://www.a-vhost-name.TLD/libraries/phpgacl/gacl_db.php
[uname!]: Linux x.y.z.w 3.2.0-43-generic #68-Ubuntu SMP Wed May 15 03:33:33 UTC 2013 x86_64 (safe: off)
[vuln!]: http://www.another-vhost-name.another-TLD/libraries/phpgacl/gacl_db.php

So if you run servers or websites, do a locate gacl_db.php.

Since all the bot/servers entering post a [vuln!] message about phpgacl, my guess is that the original vulnerability that allowed the attacker to gain access is right there. I haven’t had time to look into it yet, but I’ve warned my clients to remove this library from their websites as a precaution. You should probably do the same.

Greek PGP Web of Trust 2012 edition

I’ve very glad for hosting this guest post. Dorothea put some real effort into it. So…enjoy!

In 2008 Patroklos Argyroudis created the first visualization of the greek PGP web of trust, based on information supplied mostly by people who attended a keysigning party at Thessaloniki. You can read his related posts at [0]
In 2012, during the second cryptoparty [1] at [2], George Kargiotakis suggested if someone wanted to update the network. I decided to undertake the task and you can see some of the visualizations below.

1. Venn of persons that have signed others and of persons that have been signed by others
2. Greek PGP network for 2012
3. Trust in the 2012 Greek PGP network
4. Highlighting the persons who have signed more people
5. Do people trust more persons than they are trusted by?
6. Geolocation of individuals (globally)
7. Geolocation of individuals (in Greece)
8. Gender percentages
9. Educational and research institutes in the PGP network
10. Animation: Formation through time of associations that were active in 2012
11. Communities and the ten most important positions in the 2012 Greek PGP network according to Eigen value centrality

Additional sections:
12. Outline of methodology
13. Keyserver & keys used
14. Notes on methodology
15. Software and visualization notes
16. Problems encountered and how you can help
17. Future plans
18. Web references
19. Synopsis
20. Communication
21. Thanks