Penetration testing - service or commodity

Monday, February 23rd, 2009

We face this kind of issue everyday. There are two different approaches to web application penetration tests:

• An increasingly number of companies are buying automatic web scanners, run them, generate some results and put them in a report-shaped tin, ready to go to the client. No human interaction with the application is needed.
• Some other companies allocate X numbers of days of a highly skilled consultant to assess the security of your web application. Among many other tests the consultant will also run automatic web scanners, but that is only scratching the surface of a real penetration test. The consultant will use all his/her experience to analyse many other factors of the application.

Penetration testing is all about assurance. In the first case the client will get some useful results, no doubt about it, but what level of assurance is it going to get? The report will cover the vulnerabilities discovered by XYZ software. Is that enough? I don’t think so, but that is for the client to decide. There is no question that the report will be incomplete and many issues will be missed.

In the second scenario the client can get the assurance that the results obtained were the work of a motivated attacker focused on the application security for X numbers of days. Is that enough? Again, it is up to the client to decide but in my opinion it gets so much closer to an acceptable assurance level.

It all depends on what do you want to be protected against. The decision in yours.

Tags: information security assurance, penetest, penetration test, Penetration Testing
Posted in Penetration Testing, Risk Management | 1 Comment »

Hackers in your network are closer than they appear

Thursday, January 22nd, 2009

Our marketing department did it again! This is what happens when marketing creatives and techies get together.

From this…

you get a monitor mirror with this design…

and then you get the real thing:

If you are one of our lucky clients, you will probably never look back again to check who is looking over your shoulder. If you are not then you don’t have the assurance of having the very best security consultants looking after your infrastructure and what is more important, you will need to keep looking back.

SECFORCE is an IT security consultancy specialized in providing penetration testing and IT security consultancy. Have a look to our website if you need to protect business assets.

Tags: hackers, marketing, monitor mirror, SECFORCE
Posted in Penetration Testing, SECFORCE | No Comments »

Advantages of penetration testing

Wednesday, January 7th, 2009

Many times we are asked, what are the advantages of penetration testing? why should I conduct a penetration test in my business?

If you find yourself wondering whether or not you should conduct a penetration test, then you should try to answer these questions:

1. Is my system secure?

2. How do I know it is secure?

3. What are the consequences if someone breaks into it?

We often hear people answering these questions saying “Yes, it is secure because it was designed with security in mind”. However one can argue that penetration testing doesn’t test the design of your solution, but the real implementation of it.

We have found many good designs poorly implemented. Too many times the theory is too distant to the real thing.

You may also answer “I don’t know if it is secure or not, but I guess no one is going to attempt breaking into it”. There are many different motivations for attacking a system and the only way of ensuring that the security of your system is not going to be compromised is by securing it.

The advantage of penetration testing is that it gives you very accurate information about the real security posture of your system.

Only if you answered “None” to the third question you should not consider investing your resources in a penetration test.

Tags: advantages, penetration test, Penetration Testing, system security
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FTP bounce network scan - My printers are scanning my network

Wednesday, December 24th, 2008

Some time ago we were performing an internal penetration test an we identified a Canon iR C2880 printer within the IP range in the scope of testing. Printers is the kind of device that a penetration tester tend to dismiss as they don’t look very attractive from the attacker’s perspective.

It is a fact that printers are usually installed with all the settings by default. This includes having the default administration password (if any), default administrative interfaces enabled, default services running, default SNMP community string, etc.

It is interesting to note that some printers run an anonymous FTP server that users (and processes) can use to print documents. A user can upload a document to the FTP server running on the printer and it will be printed. Things get worse when you discover that the FTP server supports the PORT command.

The PORT command is sent by the FTP client to establish a secondary channel for data to travel over. This command can be abused by attacker to network scan other hosts on your network, as shown in the next diagram:

Why an attacker would want to do that? Well, there might be several reasons:

- The target host is not reachable from the network segment the attacker is connected but it is from the printer.
- The target host is reachable but there is a firewall filtering some of the traffic whereas the printer has full connectivity to it.
- The attacker wants to remain stealth and conduct the scans only using FTP connections to the printer without triggering any alarm from potential IDS systems.

This is an example of how the sniffed network traffic would look during an FTP bounce scan:

The network traffic screenshot shows that the attacker is using the printer as a bounce host and the only traffic exchanged is FTP based.

As you can see, IT security and penetration testing is about identifying every issue in your infrastructure and exploiting the weakest link.

Tags: FTP bounce scan, ftp port command, internal penetration test, internal penetration testing, network scan, penetration test, printer security
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why penetration test? firewall is not secure enough?

Tuesday, December 9th, 2008

A few days ago someone visited our website after searching in Google “why penetration test? firewall is not secure enough?“. We are going to dedicate this post just to that topic.

A firewall is a device connected to two different networks and with a number of rules which determine what traffic goes from one network to the other and vice versa. That simple. For example, a recommended configuration for a firewall protecting a web server is to filter all inbound and outbound network traffic by default, allowing only inbound traffic to your web server port (TCP/80).

Firewall protecting web server at the network layer

No doubts this is a good configuration which will protect the web server from many attacks. The firewall will filter network access to many services, but the question is “why penetration test? firewall is not secure enough?”. Well, the answer is “no”, with just a firewall the above environment is not secure enough. A firewall is always going to allow some traffic, otherwise it would be better removing the firewall and having both networks disconnected.

In the configuration above the firewall allows connectivity to the web server, therefore an attacker targeting the website will have full network access to it. The firewall will do very little to protect the web application.

So back to the question, “why penetration testing?”. Penetration testing is a method of assessing the security of a system or network by emulating a real attack scenario whereby a security consultant assumes the role of a motivated but non destructive ‘hacker’. In the scenario above a penetration test will highlight any misconfiguration on the firewall and, what it’s more important in this case, will identify any vulnerability affecting your website which could be exploited by remote attackers.

In summary, a firewall is a great security tool which can protect your infrastructure from some threats, but they certainly can not protect you from everything. Additially, penetration testing can be beneficial to assure that your systems and applications are secure.

Tags: firewall, penetration test, Penetration Testing, web server security
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Penetration testing, antivirus, firewalls and false sense of security

Sunday, November 9th, 2008

False sense of security is an ongoing issue. Fueled by inaccurate marketing strategies promising the ultimate security product and convincing clients that their product will make your system immune to every single attack.

Security professionals are used to hear all kind of comments from clients caught up by false sense of security; the three most common mistakes are:

Client - My application must be secure, it is running over SSL.
Penetration tester - That’s good, your IDS will not pick up my attacks.

Client - My web application must be secure, it is protected by my firewall.
Penetration tester - Sure enough your firewall is not going to filter web traffic on your web server.

Client - My server must be secure, it has an antivirus up to date.
Penetration tester - Your antivirus will only pick up known signatures, it will not pick up my custom made scripts.

We recently performed a back box web application peneration test for a client who expresed (before the penetration test) how secure his application was as he deployed SSL on the application layer, antivirus on the server and everything was protected using a firewall.

During the penetration test we managed to find a page which allowed uploading arbitrary files to the web server. When we tried to upload some of the standard web shells we saw how the antivirus was detecting them and removing them from the server. It is fair to say that an antivirus in this case provides a very thin layer of security. After doing some modifications to the scripts we easily bypassed the antivirus protection.

In this example achieving command execution required another step as the user the web server was running as had not enough privileges. However, it was easy enough finding a high privilege username/password for the MS SQL database also running on the server. The next steps were:

- Creating a custom script which connected to the MS SQL database using a high privileged account.
- Enabling xp_cmdshell stored procedures, as we found it disabled.
- Enjoying command execution.

Once we got to this point it was easy to execute Metasploit Meterpreter to bypass firewall protection, tunneling services over HTTP.

In conclusion, SSL, antivirus and firewalls are essential parts on the security of an infrastructure, however they need to be properly implemented and they don’t protect from all kinds of attacks.

Tags: antivirus, antivirus bypass, black box, false sense of security, firewall, firewall bypass, metasploit, meterpreter, Penetration Testing, web application penetration test
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Black box penetration testing vs white box penetration testing

Monday, November 3rd, 2008

One of the common questions that we get from our clients is about the differences between a black box penetration test and a white box penetration test.

White box testing, also known as clear box testing or glass box testing, is a penetration testing approach that uses the knowledge of the internals of the target system to elaborate the test cases. In application penetration tests the source code of the application is usually provided along with design information, interviews with developers/analysts, etc. In infrastructure penetration tests network maps, infrastructure details, etc. are provided. The goal of a white box penetration test is to provide as much information as possible to the penetration tester so that he/she can gain insight understanding of the system and elaborate the test based on it.

White box penetration testing has some clear benefits:

• Deep and thorough testing
• Maximizes testing time
• Extends the testing area where black box testing can not reach (such as quality of code, application design, etc.)

However, there are also some disadvantages:

• Non realistic attack, as the penetration tester is not in the same position as an non-informed potential attacker

A black box penetration test requires no previous information and usually takes the approach of an uninformed attacker. In a black box penetration test the penetration tester has no previous information about the target system.

The benefits of this type of attack are:

• It simulates a very realistic scenario

The disadvantages of a black box penetration test are:

• Testing time can not be maximised in certain scenarios
• Some areas of the infrastructure might remain untested

When commissioning a penetration test, there is no right/wrong decision about white box or black box, it really depends on the scenario that needs to be tested.

Tags: black box, penetration test, Penetration Testing, white box
Posted in Penetration Testing | 1 Comment »

Penetration testing and risk management - Consultants vs Monkeys

Thursday, October 30th, 2008

There are no doubts that penetration testing is becoming mainstream now. It looks like business are eventually concerned about security. Compared to some years ago the number of companies requesting penetration tests has increased exponentially and therefore the number of companies conducting them has incresed too.

One of the important problems affecting some penetration testing companies is that they conduct penetration tests with a very narrow perspective, they don’t put things into context. I call it monkey work. It is quite easy running an automated vulnerability scanner and produce a nice report. However, vulnerability scanners are not clever enough to know how a specific vulnerability affects a bussiness.

A typical example is XSS vulnerabilities. Depending on the context they can be devastating or just a minor issue. It is up to the penetration tester to decide how important this security issue is for the business. I call it consultant work and it is where risk management comes into the game.

At the end of the day a business man just cares about the business. If he/she is conducting a penetration test it is not due to the pleasure of learning about buffer overflows and injection vulnerabilities - it is because he/she thinks the penetration test is good for the business (due to a number of reasons such as clients trust, compliance, etc.).

Therefore what they really want to know about a security issues is:

• What is the impact for the business
• What is the likelihood of happening
• How can be solved

What they are not interested in is:

• Why stack protection mechanisms can not protect you from a heap overflow
• How you control EIP on this exploit
• Why a fuzzer would have never discovered that vulnerability
• etc…

Tags: Penetration Testing, Risk Management
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Penetration testing with IPv6

Tuesday, October 14th, 2008

Today has been released the Uninformed (number 10) magazine. As usual it is a very interesting read, with very nice and technical articles there. One of them caught my eye, written by H D Moore - Exploiting Tomorrow’s Internet Today, Penetration testing with IPv6.

IPv6 is an Internet layer protocol designed to substitute the current IPv4. The article covers the basics of IPv6 such as configuration and addressing standards.

Later in the article the author some of the common tasks of penetration testing focusing on IPv6 protocol:

Network Discovery

Van Hauser’s IPv6 Attack Toolkit contains a tool for this. The alive6 tool sends an ICMP6 packet using Neighbor Discovery protocol:

# alive6 eth0
Alive: fe80:0000:0000:0000:xxxx:xxff:fexx:xxxx
Alive: fe80:0000:0000:0000:yyyy:yyff:feyy:yyyy

Found 2 systems alive

Tools ip and ping6 can also be used for that:

# ping6 -c 3 -I eth0 ff02::1 >/dev/null 2>&1
# ip neigh | grep ^fe80
fe80::211:43ff:fexx:xxxx dev eth0 lladdr 00:11:43:xx:xx:xx
fe80::21e:c9ff:fexx:xxxx dev eth0 lladdr 00:1e:c9:xx:xx:xx
fe80::218:8bff:fexx:xxxx dev eth0 lladdr 00:18:8b:xx:xx:xx
[...]

H D More also covers the use of Nmap and Metasploit against IPv6 hosts.

It is interesting the use of socat to ‘translate’ from IPv4 to IPv6 and then being able to use the common penetration testing tools:

$ socat TCP-LISTEN:8080,reuseaddr,fork TCP6:[IPv6%eth0]:80

In the example above socat creates and binds a local IPv4 port (8080) to a remote IPv6 service which was listening on port 80. After running the command above, the penetration tester can confortably use the common web assessment tools such as nikto o web proxies even if they don’t natively support IPv6.

Tags: IPv6, metasploit, nmap, Penetration Testing
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Cisco config retrieval tool and password reuse

Wednesday, October 8th, 2008

The other day we were at a client site doing a penetration test. This was a very big deployment with almost 100 routers. At some point during the test we managed to get the read/write community string of one of the routers, as there was a script with the hard-coded credentials.

We managed to connect to the router with the SNMP credentials and pulled the Cisco config file. After that, we decoded the telnet and enable passwords and we were ready to go. We tried (with no much hope initially) a couple of other routers reusing the telnet password and they all worked. Every single router was protected with exactly the same password.

We had limited time and the prospect of telneting 100 routers pulling config files was not very appealing so we wrote a nice python script to pull them for us. We released the tool in our research section, so check it out if you are interested.

The lesson to learn here is that no matter how confident you are about the strength of your password because it can be potentially compromise and if you are reusing it, the impact for the business becomes critical.

Tags: cisco, cisco config, Penetration Testing, Tools
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