Category Archives: Platform Security

Revisiting Shodan Computer Search Engine: Oh Noes, the places you’ll go!

I’m sorry to say so
But, sadly it’s true
That bang-ups and hang-ups
Can happen to you

— Dr. Seuss, "Oh, the places you’ll go!" (1990)

Back in January 2010, I wrote a short blog post about Shodan and VoIP devices and mentioned that it’s a site well worth revisiting.  Well, that time has come, and there’s plenty more to talk about when it comes to Shodan.

What is Shodan?

It is a publicly available, searchable database of pre-scanned networked devices.  The scanning includes banner results from common services like telnet and http, and is akin to fingerprinting.  One way to look at it is like Rainbow Tables for networked devices.

What’s the risk?

When a new vulnerability is discovered, Shodan makes it easy for attackers to search for vulnerable devices without actively scanning.  For example, say a vulnerability is published about Apache Mod_Security — an attacker can easily search Shodan for vulnerable version and then launch an attack to pwn the box.

Attackers can also use Shodan search filters and really narrow down search results, by country code or CIDR netblock for example.  You do have to register for more specific search functionality if you’re interested in say, the 24 Cisco boxes in Iran with no authentication.

Pssst….wanna Pwn 7000 Cisco routers/switches?

Yes you can.  And only because some network admin didn’t know how to configure HTTP authentication.  It’s easy peasy with Shodan’s most popular search.  Click on the resulting IP addresses from that search and you’ll get the HTTP interface of a Cisco router/switch with no authentication.  Add "/level/15/exec/-/sh/run/CR" to the IP address and you’ll get the "show running configuration" output of the device.  Understand what’s going on here.  An attacker can easily add an admin-level account, change the configuration, crack the listed Cisco passwords in the configuration to target other devices on that network, etc. 

Why should I care?

Shodan creates risk by making poor configurations and other adminstrator mistakes much more visible to potential attackers.  It also creates risk by providing a pre-scanned inventory of potential targets.  I’ve seen some amazingly frightning devices discovered through Shodan that are wide open and have no authentication — for a few examples:

  • An Eastern European country’s SCADA water treatment network
  • A switch controlling the Neurosurgery VLANs of a hospital
  • Physical security door access controller systems
  • Routers with VoIP configurations
  • and plenty more….

These are just a few examples of the micro-risks.  I think from a macro-risk perspective, specifically concerning the Cisco routers with no authentication, is the very possible and easy mass takeover of routers and potential for BGP attacks.  Not possible?  Well, think back to early 2008 when Pakistan modified BGP routes to block YouTube and because of a misconfiguration, large swaths of the Internet outside of Pakistan could not access the site. This was the result of a error from a few routers broadcasting bad BGP routes — now imagine if an attacker does this with a few thousand routers distributed globally?  I think it’s really only a matter of time…

What should I do?

There are tangible steps you can take.  First and foremost if to register fora free Shodan account and search for devices on your organization’s CIDR netblock.  If you are working with buisness partners that are connected to you, check their CIDR netblocks in Shodan as well.  Make a stink and inform the right network and security people of the risks of Shodan exposure.


You can do nothing, and let Shodan determine your fate.  Your choice.

Weaponizing the Nokia N900 – Part 1

In the 80s movie “The Color of Money” there’s a great scene where a player challenges Tom Cruise’s character to a game. He strolls up to Vincent and says “So what you got in there?” — to which Vincent replies. “Doom.”

This is akin to how I felt a few weeks ago after I finally got ahold of a Nokia N900 smartphone. Calling it a phone is a bit of a stretch, as it is primarily a Debian Linux tablet with impressive hardware specs and a huge number of .deb packages available for installation…oh, and you can make cellular phone calls with it. Many people use this phone, and despite some glitches it is rapidly developing into a formidable platform for security tools and penetration testing.

Broadly speaking, the objective of this series of blog posts is to introduce folks to the tools available and the potential for this phone as a security testing platform. Given the fact I’m a bit late in obtaining this phone, some smart people out there have already started to address the n900’s capabilities and available tools, and I would be remiss not to mention, and build upon, their insightful work. The key phrase here is “build upon” and get the word out, not to steal or simply re-hash their fine work and efforts!

I’ve one caveat to this series of blog posts. As my n900 is for now a “production phone” for me in that I need to use it and can’t brick it just yet, the path of this blog series on “Weaponizing the Nokia N900” will progress from known, tested and functioning security tools on this phone — and therefore lower risk of bricking — to more advanced, edgy tools that require more tweaks and modifications, such as replacing the stock kernel. If someone out there finds this series useful, and has interest in furthering research on running security tools on the n900, I’d welcome the donation of a n900 for development and testing, and would credit them for their support. Please ping me offline if you’re interested 🙂

NeoPwn and the Nokia N900

One project to watch in particular is the upcoming release of NeoPwn, which is based on BackTrack and bills itself as the “First Ever Network Auditing Distribution for a Mobile Phone Platform” and is due for release sometime this month, hopefully before DefCon. I am fortunate to be in the BETA and will write up a blog post for this series on NeoPwn once I get full access to the NeoPwn toolset.

Worthy Resources on Nokia n900 Security Tools

1. Metasploit on the Nokia n900. ‘Nuff said.

metaspolit n900

2. Blog SimonLR wrote an excellent post on “Using the N900 for Fun and Profit” that covers several awesome tools, such as Metasploit, Dsniff, SSLstrip, Aircrack-NG, etc. He’s clearly savvy and his future blogging on tools for the n900 will be great to see.

3. Asterisk on the n900

Asterisk n900

When I added the extra package repositories to my n900, I was more than a bit surprised to see a full version of Asterisk available as a .deb package. Wow. Think about this for a moment. One can run a full Asterisk server on a phone in their pocket. The capability of Asterisk on the n900 could enable attackers to do all sorts of mischief, such as running the SPITTER tool from their pocket as a simple example. From a surveillance aspect, think of “bad people” with n900s in their pockets running Asterisk servers on their phones and connecting to each other point-to-point over encrypted tunnels — now that’s a challenge.

Stay tuned for more posts on “Weaponizing the Nokia N900” 🙂

Linux crash on a Plane!

I don’t travel nearly as as much as I used to, yet when I do I always keep a sharp eye out for the technical glitches in devices around me in travel environments. What can I say? It provides me endless amusement.

Linux crash plane

While Linux boxes crashing in airlines’ on-board entertainment systems are nothing new, and several photos exist on the Internet depicting these crashes, I’m seeing something different these days…

On my way back from ph-neutral security conference in Berlin, I took a Continental 757 back to the US and observed the passenger entertainment system headrest in the row in front of me was frozen on the the movie selection GUI. The passenger in that seat asked the flight attendant to fix the problem and the headrest PC was rebooted from somewhere up front.

So, the funny (and a bit scary perhaps) bit is the screenshot I took of the reboot process. You can see the very high resolution photo here:

Observations from the linux crash on a plane photo:

1. 172.17.X.X private IP address range

2. FTP server IP address and transfer of system log tarball to the FTP server…user is “xxxxx” — imagine what the password might be…

Some reasonable concerns:

1. Tilting up the headrest PC and peeking behind it I saw CAT-5 cable. With a small tool or hands, and big cajones, an attacker *could possibly* unplug that cable and attach it to a laptop and hop onto the entertainment network. In addition, with some imagination and the right tools, an attacker could feasibly take over some or all aspects of the headrest PCs, including perhaps the sniffing of credit cards used by patrons, or even adding some specialized content…

2. This aircraft did not have on-board wireless Internet access, but I suspect that some airlines offering this service could have network crossover connectivity to different subnets, or perhaps only relying on VLANs for separation.

In the end, we can only hope that of the several networks likely running on a modern passenger jet, that true air-gapping is taking place and these systems are in no way connected to critical on-board networks. Time will tell if this is indeed the case. In the meantime, keep an eye out for those Linux boxes crashing on planes!

VoIP on the iPhone and iPod Touch – a security warning

iVoIP clientsAt first sight, using any VoIP client on the iPhone or the iPod Touch (a.k.a. iDevices) may seem like a uninteresting thing. The reason for this is that Apple does not allow 3rd party applications to run in the background. So when a user close down his iVoIP Client he will not be able to receive any calls at all, thus defeating the reason for using VoIP on these devices in the first place.

However, if we take a look at some of the VoIP clients offerings available we notice that a few of these clients have the ability to receive incoming calls, even when the software it self is not running.

At first sight this seems to be a Good Thing – however, there are severe security implications by doing this. Users will in fact willingly, put them self under a man-in-the-middle attack.

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China’s TOM-Skype Surveillance

According to a report published on October 1st by Citizen Lab, full chat text messages from TOM-Skype users were found on publicly-accessible web servers as well as the encryption key required to decrypt the data.  Additional data such as millions of IP address, user names, and land-line phone numbers, and records of international users who regularly communicated with Chinese users were found alongside the chat logs.

From an Ars Technica article about the report:

Clearly, there are a number of problems with this discovery, starting with security. Villeneuve notes that the information contained on the servers could be used to exploit the TOM-Skype server network, and an attacker can access detailed user profiles. “In fact, evidence suggests that the servers used to store captured data have been compromised in the past and used to host pirated movies and torrents (for peer-to-peer file sharing),” reads the report. Clearly, crafty hackers already know where these servers are and how to get into them.

While troubling from an overall Skype security standpoint, it’s not much of a surprise that the Chinese government had a way to monitor their Skype users, especially with Skype being partnered with TOM Online, a Chinese company.

Since around September 2005, Chinese users attempting to download the Skype client were blocked from doing so, instead being redirected to a modified Chinese version hosted by TOM.  Did anyone really think that this modified version wasn’t backdoored?  Who wants to bet that they have keys to decrypt the voice channels as well?

Hacking ZyXEL Gateways

An interesting paper recently published by Adrian Pastor of ProCheckup discusses vulnerabilities and attacks against ZyXEL gateways, including (yikes) Remote wardriving/attacking internal networks over the Internet, among others:

  • Privilege escalation from “user‟ to “admin‟ account
  • SNMP read and SNMP write access enabled by default
  • Persistent XSS via SNMP
  • Poor session management allows hijacking of admin sessions
  • Authentication vulnerable to replay and password cracking attacks
  • Disclosure of credentials
  • Considering the code reuse among various products made by most vendors of these residential gateways, not to mention the widespread deployment by service providers, I think it would be quite interesting for VOIPSA folks to expand on Adrian Pastor’s work and pursue this type of testing on some of the VoIP gateway products that ZyXEL offers, specifically the Analog Telephone Adapter, Station Gateway and Integrated Access Device to start. Also, the web interface of embedded devices like these are especially problemmatic from a security perspective, and it’s well worth a look at another one of Adrian Pastor’s papers over at OWASP.

    “So what” you might say about the security of these types of devices? Well, SANS diary notes some strange things afoot at the Circle K with Dlink, and there is the recent BT Home Hub CVE-2008-1334 vulnerability. More routers and details at GNU Citizen’s router hacking challenge.

    Isolation vs. Integration

    I’ve long been a staunch opponent of the “isolate your VoIP network from your data network” strategy. I personally believe that by putting up such restrictive barriers as would be required to provide any sense of actual security, the owners and administrators of a VoIP deployment are severely limiting the potential value they are able to receive from using Internet telephony. One of the Great Promises of VoIP is the ability to integrate communications with other productivity technologies such as work-group software and CRM applications. A lot of VoIP security practitioners tout the isolation strategy as a solution for the insecurity of the VoIP core devices and endpoints when in reality it is little more than a stop-gap, and not a very good one at that. By providing a false sense of security by way of network isolation, many VoIP deployment administrators may become complacent and pay less attention to the security posture of the actual VoIP devices and endpoints themselves. If you plan to integrate your communications system into the data-flow of your business in even the most minimal way, you’ll find quickly that most types of isolation that are available either provide a barrier to the desired functionality or open up so many holes in the barrier that it may as well not be there.

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