Discovered by: GoSecure!
Date of discovery: 16 september 2016
First contact with vendor: 18  september 2016 – Case Id: 01702458
Patching date: 24 march 2016
Full Disclosure: 25 march 2016

Details:
A cross site scripting web vulnerability has been discovered in Veeam Backup Enterprise Manager Service v9.0.0.902.
Authenticated users are able to inject own malicious Java Script codes in order to spoof session of other users of the affected web-application.

The issues are located in:
1 – Configuration > Search Server > Add > “DNS name” field – reflected XSS
2 – Configuration > Backup Server > Add > “Server description” field – stored XSS
3 – Jobs > “Description” field – stored XSS injected via remote backup server

The security risk of the client-side web vulnerability is estimated as medium with a Overall CVSS (common vulnerability scoring system) Score 4.1 .The attackers can spoof session or emulate every action that the victim can do in the web application.

Proof of Concept (PoC):
The cross site scripting web vulnerability can be exploited by authenticated user that may want to make a privilege escalation or impersonate another user of the web-application. For security demonstration or to reproduce the vulnerability follow the provided information and steps below.

1 – Configuration > Search Server > Add > “DNS name” field – reflected XSS
Attacker injection and activation:
– Go to Configuration > Search Server
– click on Add button
– insert the following string in the “DNS name or IP …” field and click ok
<iframe width="300" height="150">
– the script is activated

2 – Configuration > Backup Server > Add > “Server description” field – stored XSS
Attacker injection and activation:
– Go to Configuration > Backup Server
– click on Add button
– add a server and insert the follow string in the “Server description” field
<iframe onload=alert('GoSecure!')>
– point the mouse over the description of the new server: the script is activated

Otherwise edit the description of an existing server

3 – Jobs > “Description” field – stored XSS injected via remote backup server
Attacker injection:
– Go in a “Veeam Backup an Replication Server” that is managed by the “Veeam Backup Enterprise Manager Server”
– In “Home” > “Managed server” click on a job (eg. File Copy)
– Create e new job and insert the following description:§
<iframe onload=alert('Peru GoSecure!')></iframe>
– Complete the creation of the job and click finish.

Victim activation:
– Go in the Enterprise Manager web interface
– In Jobs, point the mouse over the description of the new job: the script is activated.

Note that, although this third issue is not unauthenticated, the problem can be that an evil user can create Job in a remote Backup server and inject code in another server/app in order to get e session in the Enterprise Manager Server
The JS injected, using POSTDATA as payload, can do every thing the victim can do in the web interface of the Enterprise Manager Server

Remediation:
https://www.veeam.com/kb2114

https://barracudalabs.com/research-resources/bug-bounty-program/bug-bounty-hall-of-fame-2/

Let’s try to run WCE using the -w option. Note that you must be a priveliged user to run this tool.

It’s pretty simple: WCE shows every passwords cached; in clear text.
Let’s assume that the pc CLI01 is joined to a domain and let’s see what happen if some service is started using domain admin password:

WOW! The domain admin password stored locally is showed.

How many service are misconfigured in your network? Let’s hope very few because you are a very good sysadmin and no service starts with domain sensitive password, but what about social engeneering?
Each time a user is begging for a password for an installation or he asks to you something that leads to digit your admin password on his pc, is it a legittimate request or does he wants your password cached?
So, you domain admin, what kind of password do you use on company users pc? The domain-admin-super-God password or the local pc password?

Basing ourselves on this and the previous post let’s now compile an hypothetical roadmap from simple user to domain admin:
1- Boot the company Microsoft PC using a CD/DVD with a bootable operating System
2- Use the sethc “feature” to become local admin
3- Begging for a domain admin password (“Please I need the latest java update, but I need your password”, “I’m trying to add a new charset, but the pc is asking for an admin password…”)
4- Run WCE and become domain admin
5- Use some other tool like pstool and collect the password of every user of the network

I think that these are the defences that a network/system admin can adopt:
1- No external device boot allowed and PC and case locked
2- No remediation on this (may be some domain policy). Remember that also Linux has a level 1 booting.
3- Users are invasive and dangerous, even if they don’t want your password. So Always log on their PCs always with the lowest privileges you can.
4- WCE must blocked to users (AV rule, policy, firewall)
5- If an attacker reach this point you will probably spend the next weeks searching another job in another city

The scope of this post is to make system admininistrators and everyone else aware on how to take care about IT security.
Many times, working as sysadmin, we make mistakes, we are pressured and we sometimes left open ports saying “I will patch them later”, but we always have to remember what risks we are taking.
An attack, talking about computer and network, often starts from the bottom and, little by little, try to reach the top; a small door open gives the way for another gate an so on. This process is called Privilege Escalation.

Discovered by: GoSecure!
Date of discovery: 30 march 2014
First contact with vendor: 31 march 2014 – Case Id: 2-199617
Patching date: 19 may 2014
Full Disclosure: 3 june 2014

Four injection points were useful to create a persistent Cross Site Scripting. All the injections are reached using default Web Client interface, but the Web Client Lite seems to be not vulnerable to these tests.

1. Contacts section:
A persistent XSS can be reached adding a new contact with a specific string in the Name field and whatever image:

PoC string:
Go<iframe width="300" height="150"></iframe>Secure!

When the contact is saved and on mouse over the picture the Name is been displayed in a bubble activating the JS:

2. Contacts section:
A vulnerability can also be reached in the Adding Group task.

PoC string:
<iframe src="https://www.gosecure.it" width="500" height="500" frameborder="1" align="center"></iframe>

3. Calendar section:
A persistent XSS can be reached adding a new event in the Calendar; this event can be spread adding the Meeting Request option.
Since, using this injection point, the XSS can be spread to other users, this is the most dangerous of the four and can be used to spoofing sessions and therefore compromising the attacked users account

The JavaScript is executed simply viewing the calendar or when the Reminder pops up.

PoC string:
GS!<iframe width="300" height="150"></iframe>

4.Task section:
In a similar way also the tasks are vulnerable to persistent XXS.

PoC string:
<iframe src="https://www.gosecure.it/blog/remote/xss_h.html" width="300" height="150">

This is an old method that I rediscovered after many years and, with big surprise, is still present on modern MS operating systems (win 7 and 8).
At the base of this “feature” I’m going to describe there is a windows executable: c:\windows\system32\sethc.exe (but it’s not the only way: you can also use shutdown.exe).

If you have a Windows system you can activate this program by pressing 5 times the left SHIFT, this operation runs the executable (sethc.exe).

There are two problems if you analyze this situation: first it can be runned also in the login screen before authentication, second the privilege used to run the executable is SYSTEM (in the login screen no user is already logged in)
This is quite terrible.
Before, in XP sp2 and early xp sp3, this file was used to escalate privilege whitout phisycal access to the pc: the file was accessible by everyone and was not locked by the system, so a user could remove the legittimate sethc.exe, copy the cmd.exe from the same folder and rename it in sethc.exe.

What was the window that poped-up when the user hits CTRL for 5 times after this alteration? A CMD shell! What was the privilege of this shell? System!
Luckily Microsoft patched this problem in late XP sp3 and now the file is locked and can’t be manipulated when the Operating System is started, but the setch.exe is still there.

Some weeks ago I had some problems to access a windows laptop (win 7 SP1). Although I had the authorization to access to it I didn’t have the password to enter and no options to recover it. so I tried this:
I put a linux bootable CD and boot the pc using it. Then I simply mounted the windows file system and used some command like this:

Than I rebooted the system from HD and, when in the login screen, I simply pressed 5 times the left SHIFT.Ta-da! I got a SYSTEM shell.
I used a basic command line to create a new user and put it in Administrators group and, less than 5 minutes later, I had the full graphic control of the box.

This caused me a hundred of ideas, so, put aside this latop, I went on with my tests.
I tried it over a Win8 box, on a domain PC and against a server with strong domain policy and every time it worked fine.

So this is my assume (but you can refute):
If you have physical access and if you can boot from an external device (using bios or physically adding a new HD to the pc case) you can log into a Windows pc using SYSTEM privilege.

That’s why in every Company, that believe in IT security, the external device booting, the PXE, and the access to the PC case must be regulated.

ASAP I will write some example to become Domain admin strarting from this point, to highlight how dangerous is every litle door that a sys admin leaves open.

This is an exampre of how the function works:

In spite of this, as you can see, some sensible chars aren’t escaped like the % that can be useful in a LIKE query.

The mysql_escape_string have some vulnerability partially patched with the mysql_real_escape_string.
Particularly mysql_escape_string don’t require authentication and can be insert before the mysql_connect function.
This means that it doesn’t verify the database character encoding, but analyzes and sanitizes the string one byte at time also if the batabase encoding is multi bytes (GBK, UTF-8, Big5).

Take a look at this example of mysql authentication using PHP code:

If we suppose that the db encoding is GBK (in this case I forced it in the PHP code: mysql_query("SET CHARACTER SET 'gbk'")) we can try to take advantage of the use of different encoding type.
First of all let’s try to use PHP to see difference between GBK and ASCII, before and after mysql_escape_string()
Use the follow php sample:

Image 1

Now modify the previous sample and load it:

Image 1

Ok, the string that reaches the MySQL will be \xbf\x5c\x27; now, if the charset on MySQL is GBK, the behaviour will be the same of the PHP page: a kanji and a single quote that is what we need for a SQLi.
In the image 3 you can see actually the result:

Image 3

The only encoding I found to be vulnerable are GBK and BIG5 because are the only that have \x5c as second byte of an allowed character.
But you can explore more by referring to this site.
Also I can’t find a way to force the DB chatset before MySQL connection, so I suppose that SQLi can be reached only if the GBK is already the BD charset.

You can try to read the following posts to get more info about mysrl_real_escape and this kind of vulnerability:
https://security.stackexchange.com/questions/8028/does-mysql-escape-string-have-any-security-vulnerabilities-if-all-tables-using-l
https://ilia.ws/archives/103-mysql_real_escape_string-versus-Prepared-Statements.html
https://stackoverflow.com/questions/5741187/sql-injection-that-gets-around-mysql-real-escape-string
https://stackoverflow.com/questions/3665572/mysql-escape-string-vs-mysql-real-escape-string
https://www.sans.org/reading-room/whitepapers/application/web-application-injection-vulnerabilities-web-app-039-s-security-nemesis-34247

I’m not talking here about the exploit, but only about the shellcode creation and choices motivations. This exemple can be easly fit to other situations and replicated without inserting it in an exploit, but simply tested in a developer or in a custom binary file.

I started from this sample code. It uses the Windows API function MessageBoxA to popup a message

Looking up the MessageBoxA function in Google reveals four arguments:

So the sample code pushes in the stack all the arguments and then call the address of the function already loaded in memory.

Some things to underline:
– at the end of every argument a null byte is insered (\x00)
– the arguments are pushed in reverse order into the stack (LIFO)
– this is only a shellcode and it has to be appended to a program; this program must have the function MessageBoxA (user32.dll) loaded in memory.
– the address of the function (0x7E45058A) is hadrcoded and works only on the Operating System the shellcode is written for.
– the hardcoded address doesn’t work in random space address context (ASLR or EMET)

Starting from this sample I want to use the System() function to pass commands to the interpreter (typically CMD.EXE); I search in MSDN specifications and I found that it needs only one parameter: the command I want to pass.

First I have to determinate, using the debugger, if the function is loaded in memory, so in Olly I search for “Names in all modules” and, luckly I found it in the msvcrt.dll (Figure 1) at address 0x77BF93C7 (Figure 2).

Figure 1

Figure 2

So the testing shell code will be like this:

Ok, now I have the test shellcode; I can do it directly in Olly. I open the debugger, attach a program, edit the first few lines, put a brake point at the end of my code and run the program (Figure 3).
Remember that the msvcrt.dll must be one of the module loaded by the program attached to the debugger.

Figure 3

Note that the net user/net localgroup need the admin privilege to be executed, so in a real exploit the target program must be started using elevated rights. On the other hand the first command, the echo one, will work also with low privilege.

The Password Attacks on Kali Linux [Part 2]

Offline Password attack
The service that use as authentication a keyword needs to store it somewhere and somehow. Think about /etc/shadow or SAM in Windows, but also browsers, routers, switches and any kind of client (ftp, e-mail, smb). The password can be stored in clear text, in databases or hashed in files; every time you copy these files and then you try, even in other environment, to extract the passwords you are doing an offline password attack. With administrative rights is possible, for example, to dump password hash from Windows and Linux system. The same operation can be done mounting the target system disk on the Kali system, also without credentials, or starting the system to attack using a bootable Kali distribution.
Files that contain hashed or plaintext passwords can be found in every place: sometimes the database backup is directly hosted in a web folder, let alone files named password.txt that can be found directly using Google; also htaccess and htpasswd can be dumped sometimes. FTP client, zip files, RDP connection files are a mine of keywords easy to collect too. Sniffing traffic waiting for a pop3/ snmp clear-text request or taking a 4 way handshake from an access point are just other options you have to perform an offline attack.
Remember that keys are often reused throughout the network, so a complex password simply sniffed with Wireshark in a not encrypted packet like pop3 (see Figure 1) can be the same unbreakable and encrypted 15-chars password used for ssh service.

Figure 1

Windows SAM file and Linux shadow
Windows stores the hash of local passwords in a file named SAM “Security Accounts Manager” present in c:\windows\system32\config\. Of course the file isn’t plain text, but it has to be merged to another file (SYSTEM) present in the same folder. The union of these two files leads to a readable one where you can see the passwords hash just like thise in Figure 2.
These two files can be accessed only when the operating system is down or using tolls like PWdump or FGdump. The other choice is to dump the system backup of these; in fact, up to Windows Vista, you can find them in c:\windows\repair\ folder. To merge the SAM and the SYSTEM file you can use bkhive and samdump2; after getting the hash, John the Ripper is used to extract the password.

As said previousely, if you own the target machine, you can take advantage of tools like FGdump too or, if you have established a meterpreter session, of the hashdump command (see Figure 2).

Figure 2

Note that you need to be Admin or System to launch these commands and you have to upload to the target machine some lines of code that sometimes can be blocked by antivirus.
Since it’s one of the “most wanted” tools, let’s see also JtR in action:

Note that most passwords are immediately decrypted (nina, administrator, user, jasmine, albert, peru) when others only in part.
This is caused by the old windows method to store password called LM. This kind of hashing, putted next to the newer NTLMv2, is present by default up to Vista to guarantee the backward compatibility. LM can be disabled and Microsoft recommended that, but de facto this is a vulnerability that users are carrying on for many years.
The LM hash works as follow:
• the user password is converted in an all upper case string;
• the password is cutted after 14 bytes (max password length);
• the password is splitted in 2 pieces of 7 bytes max;
• this two pieces are encoded using DES.
This is a simple view of what is LM, but your interest is that JtR has the task to crack an hash with no more than 7 chars-upper-case. This is really different from finding a key with 14 chars, upper and lower case. in addition to this DES kind of encrypting is well known and john use this to speed up the work.

Also, Linux stores keys in two files: /etc/passwd and /etc/shadow. In this case it’s not essential the merge of the two files, but it’s better for decrypting. You can use the JtR command unshadow to join the two.
In Kali Linux you will be able to call any tool from anywhere on the system as every application is included in the system path so you can call unshadow and john just like this:

Then you use john to decrypt:

Sometimes you can try to use john on /etc/shadow without unshadowing it, but in this case john will not use the GECOS info (complete name, telephone number…) that helps to perform a better crack. Also the use of some features like -shells will be lost if you don’t perform the unshadow.

Some small words about using Google as hash cracker.
Google is a big container of everything. It’s not unusual to take an encrypted string, paste it in the browser and find the key.
One of the easiest hash to find is the MD5 one. The Message Digest algorithm 5 is an old method of hashing; it is already obsolete and insecure, but users and programs still employ it to encode passwords. If you try to paste an MD5 string in Google you’ll likely find it. Before trying everything else paste the hash in the search engine or use some online rainbowtable program.

The cache and the sniffing
Although the cache and the packet analysis are not pure offline password attacks, they deserve to be mentioned. If you finally own a PC in the net you have to test, squeeze it. Extract all what you are able to take.
First start a sniffing session using Wireshark or, if you can’t, use Ettercap to perform a man in the middle and wait for unencrypted password. These are some normalized output of Ettercap. The first is the capture of a webmail account on an insecure http page instead of more secure https:

Then some capture of POP3 and FTP packets:

This is why is always better to use an ssl version of all protocols, also in internal communications.

If you have access to a PC search for client’s programs like FileZilla or browsers and take note of passwords archived using meterpreter or search in Internet where the client stores it:

Then use ms-cache option of JtR or program like Windows Credentials Editor that locate system cached password: if you are lucky a sysadmin has been logged or some service is misconfigured and the password is stored (not encoded) in the cache.
In the following case of study the user HP\Nina, present in Domain Administrators group, is simply logged on. In this machine is present an agent misconfigured that use HP\administrator credential to work:

Note that cache keys “ninaanin” and “password” are not encoded.

SMB pass-the-hash
Like in the previous example, not always you’ll have to spend time in decrypting operations. Sometimes you can use the hash you get as it is. Ok, you can’t take the string and just paste it in a authentication window request and login using Remote Desktop, but there is a quite controversial feature in Windows on the authentication management of shared folders.

Consider this example:
Computer A has a c:\share and Computer B tries to connect to that share. B sends its credential in hash format (“hello! I am Administrator and my password is e52cac67419a9a224a3b108f3fa6cb6d”) and A verify if it has this credential, if so it connects Computer B to the share. If not it prompts for username and password.
All this process is in clear text!
So, what about If the Computer A is an attacker and has a network sniffer? It collects the Computer B hash! Now attacker on Computer A can try to decode the hash, but not only that. He can use Metasploit, taking advantage of the module pass the hash, and own the B machine.
He uses the Administrator hash to connect to ADMIN$ of B and execute some code like reverse shell. The SMB_relay exploit, present in Metasploit, has everything you need to test this Windows vulnerability: it creates a fake sharing folder, captures the hash, pushes a payload and establishes a connection. Of course the pass the hash function can be also used with hashes previously collected:

Are you still secure to connect to a network shared folder? So, if you have to secure a network, remember the users: force a strong domain policy, patch the systems, use SSL wherever you can, set different passwords for different services and, above all, educate the people.

The Password Attacks on Kali Linux [Part 1]

What is the weakest part of the security chain? You know the answer: the one who stand between the keyboard and the desk chair. And what does this user do on her/his first job day? Set a password. Yes, a big part of our security environment lies around that password.

Of course we talk about internal password because Nerwork Administators have well learned the lesson and secure their external accounts with encryption, strong policy, access restriction; in spite of this the internal accounts are the heaven for hackers (and the hell of sysadmins).
Nowadays internal users are, fortunately, low-privileged and some kind of policy forces a little of security, but even if your policy is set with more than 8 characters with numbers, upper and lower case, there will be a user that set as password something like AAAAaaaa1 or Password1.

The complete takeover of a net is a stairway that goes through information gathering, network discovering, password cracking and system owning. Also, finding a low-privilege password is one stair over and it’s actually one of the biggest gap that a penetration tester has to pass. If you find a password, you can quickly test it on other systems and services previously discovered (ssh, ftp, mail): users have the bad routine to use the same keyword for different services.
When you discover a password, you can make an idea about the security company policy and you can try a widespread brute-force attack. If you find, for example, a key of 8 characters, all low case, you can try an attack using this setting on all systems of the LAN. Even if you find a key word from user that isn’t administrator or root there are lot of well-known privilege escalations that can be attempted, especially for old or unpatched system.
Other options that can be used, when you owned a PC with an unprivileged account, are: sniffing traffic,
extracting stored credentials or pivoting other attacks. All these things lead you over and over inthe stairway. In substance, a right association user-password is one of the core success on a pentest and it’s all trusted to an user and his password, that he has chosen on his first job day.

Some terms
Let’s start making a specification. There are two common names you can hear talking about password attack: BruteForce and WordList.
Brute force is when the password is tested using all designated characters, using a set length. The following is an example: use character ‘a’, ‘b’ and set length 2. The password that will be tested are aa, bb, ab and ba; these are 4 tries. You can calculate the amount of attempts: quantity of characters elevated to length used, in this case 2^2=4. Because it is an exponential, it can be become very difficult to test something with ten characters using full ASCII set: according to Password time calculator by lastbit.com this BruteForce attack will take up to 4274902 years.
BruteForce attack, but a WordList one, where what will be used as keys are all single words present in one list.
Note that the password used is exactly the same written in the list. So if in the document there’s the word ‘backup’ only this word will be tested and not ‘Backup’ or ‘back-up’; fortunately there are programs that make these permutations automatically.
So wordlists are often a smarter attempt than a bruteforce attack; in spite of this, during a pen test, you must have a very strong reason to spend hours for this kind of attack.
Of course the following password attacks are done using Kali Linux, because it has every tool you’ll need. Thanks to OffensiveSecurity, Kali Linux, like its father BackTrack, is one of the most used pentesting distributions. If you are reading here you known what we are talking about.

Create your user and password list
To perform a wordlist attack you need, of course, a list of words. There are many techniques to create it, and many places where you can find a precompiled one, but the best way is to create a document based on your needs. From my personal opinion, in this case, is necessary to start from locating valid usernames from the network I‘m testing and using these as a first simple list, trying blank, username as password or very simple passwords.
The harvest, by Edge-Security Research, is a very useful tool that helps you by searching for a company name in various resources database (Google, Linkedin, PGP, Bing…) and then extracts for you probable user names. In the Figure 1 you can see the result of a research: maybe vdiaz, cdelojo and cmartorella are also FTP, SSH or RDP users.
Then you can try to locate some useful accounts from the company website: e-mails and documents such as pdfs, docs or similar can be downloaded to gain such information. You can automate the operation by using another tool by Edge-Security Research: metagoofil (see Figure 2).

Figure 1

Figure 2

Another way to find usernames, when you are in the testing-Company LAN, is to locate a mail server and an SNMP service. Mail server can be vulnerable to VRFY command and you can use it to probe the system for login names. The VRFY is a licit command and fortunately, in modern system, is disabled to patch this security issue, but sometimes you can still use it. Let’s look how it works using a simple Netcat connection:

If the system is vulnerable, smtp-user-enum program can be used to get some usernames; the following is the basic command to use it:

Note that the option -U uses a wordlist in order to find names. If you haven’t one you can find some preloaded in Kali using a command like this:

However the suggestion is to keep your list under 100-150 names. Smtp-user-enum can also be used to test the EXPN function; EXPN is similar to VRFY, but it is used on distribution list and it lists all its users. This can be a bigger problem than the VRFY since sites sometimes have an alias such as “all”.
Another way to compile your focused user list is SNMP analysis. SNMP is a protocol based on UTP that is often used to monitor servers’ service status.
The distribution lists (community strings) are passed in clear and often have the default state (public or private), so you can easily try to find it in order to query the server and get many information.
You can use a combination of Onesixtyone and Snmpcheck; the first can be used to enumerate community strings, so, after locking on the hosts with SNMP service, the program can be run.

The dict.txt is a wordlist (another one) of possible community strings and it is already present in Kali; the host-snmp.txt is a file with the IPs of all hosts with the SNMP service active in the network. The word in the square brackets (see Figure 3) is what you are searching for and the next step is to use this word combined to Snmpcheck to extract data from the service.

Figure 3

In this example the output is limited to the user accounts (grep -a “User accounts” -A 11), but you can get much more info using SNMP such as processes running, programs installed, open ports, network and routing configurations, storages information and much more.

There are several ways to find a username in the net: if something similar to PC-pedro or Maria’s MacBook is found the assumption is that Pedro and Maria are likely to be usernames that will have access on these computers. It’s important to compile the user list meticulously and add every possible username you find, so you can use it later.

Finally you have a user list that will help you in a first simple password attack.
If you will have no results you’ll wish to make some simple extensions to that list using John the Ripper (JtR) or you’ll try another small wordlist like /usr/share/john/password.lst; also in this case JtR can be used to make some little changes.
Let’s see some usage of John the Ripper password cracker by Openwall. Note that this program does more than what you’ll read here. You will see now, how make some simple mutations in order to upgrade your user list and use it as a password list.
The idea is to create something that leads from an input as ‘root’ to an output like Root, ROOT, rootroot, toor, Root1 and so on. Well, let’s expand a small file (wordlist.lst) with only ‘root’ and ‘password’:

In this case a default rule set is used (--rules), but you can modify it using /etc/john/john.conf; note that with 2 words JtR generates 100 words instantly.
The output is normalized, in this case, using tr -s '\n' ' ', but you can remove this part of command and redirect all in a file that fits your needs. Later,
talking about offline attacks, you’ll come across JtR again and you’ll find some other awesome features. Even though, I think, using a huge wordlist is not a good idea, it can be useful to know how to make it, so here are two great tools.
The first is CeWL, you can use it to dig a Company web site to extract words and convert these in a list. The basic usage is very simple and the impact awesome:

You can even use it to extract usernames by pointing CeWL to sites that collect popular birth names. Similarly you can use it to create monothematic wordlists: animals, plants, countries, cars, “Lord of the Rings”, topic words and so on.
The concept I’d like to remark is that in an online password attack you are connected to the LAN: you make network traffic, you stress systems and you can’t stay there all night and day long.
The second tool is Crunch. It can be used to create a word list too, but starts from a different point of view compared with CeWL. Crunch is more like a bruteforce: it generates all words using some parameters you set. Essentially you establish min and max length and a charset (or use the default one); so you can create all possible combinations of characters a, b, c with length from 2 to 4 using the following command:

More specific and interesting usage can be read in the manual page, like the -t option: you can take one word and append some characters to it:

The output can be sent to the screen, to a file, or to another program; this last option allows the use of Chunch directly on an online/offline cracking operation without physically generating a wordlist, saving hard disk space.

Online Password Attack
One of the best tools to complete the online attack is Hydra. This program is tasked to join your lists and to perform the attack over a network service.
The figure 4 explains how it works: it puts together a username list, a password list and a host list split by services to attack (FTP, RDP, SSH, MySQL…).
Then it starts to try every username and password associations on every hosts. Some other parameters can be set such as proxy or the number of tasks; very useful when attacking some cranky service like RDP.

Figure 4

The following is the command that performs a wordlist attack against all FTP hosts in the net:

The -L, -P and -M options are used to point to the wordlists of users, passwords and hosts and can be replaced by -l, -p and a IP to use a single name, password or target. -s is the port to attack and the ftp at the end is the service used as target. -V stands for verbose and -e option tries n null password, s login as pass and/or r reversed login. Finally -t is the number of task that Hydra will use.
The simplest way to learn the use of this tool is to take a look at the GUI xHydra (see Figure 5).

Figure 5

Hydra is the end (maybe happy) of the online password attack, but it is no more than a task executor. Its force lies in the wordlists you will be able to create, don’t forget this.

[end of part 1]

Some scenarios:
– Sniffing traffic
I setup a RAP and start wireshark, ettercap or another network sniffer. Every connections that pass through my PC are intercepted.
– Phishing
I setup a RAP and force it to use mine DNS Server. If someone will connects to me and start to surf I am able to redirect traffic using my DNS. In this case I can implement some kind of phishing.
– Company network back door
I setup, may be using a small RaspberryPi, an access point using the Company network as wired interface. This is an hot spot directly connectet to the Company LAN.
– Caffè-Latte attack
Locoking at the wireless packets you can see the client trying to connect to the previusly registred access point (eg. MY_NETWORK). I Can setup an access point using the same SID the client is searching for. When the client, that is serching for a known SSID, find my RAP named MY_NETKORK it immediatly try to connect. I can use this connection to sniff WPA handshakes or WEP packets and try to decode passwords.
– Extend my connection
I have a notebook connected to a LAN but no access point. I also have a smartphone and I want a wireless connection on-the-fly.

The basic configuration:
– eth0, the wired connection linked to the network
– a DHCP server working on the LAN where eth0 is connected
– wlan0, a wireless interface able to be setted up in monitor mode

I start the monitor mode on wlan0:

This will create the mon0 interface.
Now I setup an AP on mon0, named “MY_network”, channel 11 and WEP autentication. I can also set it as a free wifi without password (airbase-ng --help).

This will create the at0 interface.
Now the AP is started, in another terminal window I make a bridge named rougue-bridge and link at0 to eth0 using the bridge-utils. Note that in Kali Linux the bridge-utils have to be installed (apt-get install bridge-utils) in order to use brctl command.

I can release the IPs of eth0 and at0. This is because the two interfaces are now integrated in the virtual bridge and don’t need an IP anymore:

I need also the IP forwarding:

At the end I configure the test-bridge. Differently from eth0 and ap0 the bridge needs an IP of the LAN where eth0 is connected.

Note that these are temporary operations that will be discarded by rebooting the system.

Extra
Starting an AP to sniffing handshake.

-z sets WPA1 tags (2 = TKIP)
-W set WEP flag in beacons. The option -W 1 is recommended when using -z or -Z
-F where to store the cap file.

Here’s my old simple script to start a Rougue Access Point using Linux Bash. It may need some adjustment, but I think it will work.