Why won’t my call go through? Denial of service in the cell phone network.

Recently, some of the major cellular carriers have released “Network Extenders”, also known as femtocell. The network extender is a device that a subscriber purchases to extend the reach of the cell phone network. (In effect, the subscriber is paying for the privilege of increasing the cellular network coverage. What a deal!)

The network extender is conceptually similar to a Wi-Fi access point. Both connect to the Internet via wire, and both provide wireless services. While the Wi-Fi device provides Internet services, the femtocell provides cellular services.

The femtocell basically appears as a new cell tower to cell phones that are within its range. And, the femtocell will process calls for any and all cell phones that successfully register with the cell phone while is it connected to the Internet. Effectively, the femtocell is just a new gateway to the cellular network.

It is not possible for the cell phone owner to choose to connect to the femtocell or to a regular cell tower. The decision on how the cell phone connects to the cell network is made by the cell phone and the “cell tower”. And, this did not used to be a problem, when only the cellular carriers were putting up cell towers. However, the release of the network extender has allowed individuals to deploy cell towers.

Recently, I encountered a denial of service issue with a cell phone that I tracked back to an issue with a femtocell. A cell phone has registered with the femtocell to connect to the wireless network. However, the femtocell lost connectivity to the Internet. (Remember, the femtocell is a gateway that uses the Internet to connect to the cellular network.)

Since the femtocell still had power, the wireless side was still active. This meant that any cell phone that had registered with the femtocell thought that it was still connected to the cellular network. However, the femtocell had no ability to connect to the cellular network, since the Internet was done. It appears that the current cell phones do not have the ability to determine if they are connected to a cell tower that is active.

Thus, the cell phone could not make or receive calls or text messages. And the user had no ability to tell the cell phone to switch to a working cell tower. The only was to get the cell phone working again was to move to a different area, outside of the range of the femtocell. And, the cell phone reported 3 or 4 bars during the entire outage.

Until the carriers improve the algorithm that a cell phone uses to ensure it has an active cell tower, about the only thing the subscriber can do is use a Voice over IP (VoIP) application as a backup to the standard phone. And, this will only work if the VoIP application can use the Wi-Fi network for calls. And, if that is not possible, use email, which should still work via Wi-Fi if the cell tower is not functioning.



SCADA and security

A recent article  by Hal Hodson of Information Age reports that the FBI has publicly stated that hackers have successfully targeted SCADA systems in three unnamed US communities. The attacks were reported to have the potential to shut down electricity at a nearby mall as well as the potential to dump sewage. Just weeks earlier came an announcement from the Illinois Statewide Terrorism and Intelligence Center that claimed a water pump failure was caused by a hacker attacking the pump control system. The failure came from the attackers repeatedly turning the pump on and off. (The Illinois hacking attack has been refuted the FBI, so then it must not be one of the three sites reported above, right?)

So, what exactly is SCADA? Supervisory Control and Data Acquisition. SCADA systems control power production and distribution, such as those used for the generation of electricity or the delivery of water to communities. They are basically used to support the infrastructure that we rely upon. Thus, the failure of SCADA systems can impact a large number of people.

In a display of the potential damage that can be caused by an attack on the SCADA network , let’s look back to Stuxnet . This malware was reported to have targeted very specific Siemens based SCADA systems. (The attack was so specific that there was speculation that the purpose of the malware was to damage the nuclear facilities of Iran.) While details are hard to come by, it appears that the Stuxnet attack resulted in damage to centrifuges. (The centrifuge is used to separate different isotopes of uranium.)

Stuxnet caused incorrect data to be reported, which lead to the control systems effectively “mis-operating” the equipment. This “mis-operation” then resulted in damage. Stuxnet further revealed that it is difficult to prevent SCADA systems from malware attack. Theoretically, Stuxnet should not have been able to infect the SCADA systems controlling the centrifuges. However, in practice, it did because somehow the malware was introduced, either through an Internet connection or carried in via a USB. This reveals the risks of taking SCADA systems that are already network capable systems and making them accessible via the Internet.

So, you would think that a malware infection such as Stuxnet could not happen again. Not so fast, as Iran has reported that they are now dealing with another virus, the Duqu virus, that is targeting their civil defense system.

Well, what can we learn from all of this? Certainly, virus scanners are less effective now, especially against a determined adversary. Therefore, it truly is important that SCADA systems be shielded from the introduction of malware, whether it is via the Internet or through a USB device.

As consumers, we all have an interest in the security of the SCADA systems that manage our power, our water, and even our prisons.

How to find hidden passwords (and how to protect them)

While preparing to teach a computer forensic workshop, I discovered a new live Linux distribution entitled C.A.IN.E, (Computer Aided Investigative Environment.) This software is one of a few live Linux distributions that allows a user to boot Linux from a CD or DVD and start a forensic investigation. The distribution includes tools to make forensic and analyze forensic images. Since it is freeware, it is easy to make use of the software as part of the workshop.

In addition to Linux tools, NBCAINE version 2.5 includes WinTaylor, a set of tools that are designed to run on a Windows system.This software can be loaded onto a USB through the “dd” utility. (Once loaded on the USB,  a user can boot the live distro off of the USB and not access the WinTaylor tools or plug the USB into a running Windows system and access the WinTaylor tools.) Included in the WinTaylor section of the software are Windows based tools from NirSoft that allow a user to recover passwords saved in popular web browsers, view recent file activity on the Windows system, view information about USB drives attached to the computer and more.

The NirSoft tools include some noteworthy ones that are designed to uncover passwords stored on Windows systems. For example, when you log into a password protected website, Internet Explorer (and other browsers) give you the option to save the login information so that you don’t need to enter it the next time. A Nirsoft utility, iepv.exe(Internet Explorer Password Viewer), retrieves and displays the userids and passwords. If you use Microsoft Outlook and save your POP3 or IMAP password,  the Nirsoft utility mailpv.exe will retrieve and display the accounts and passwords saved in Outlook. And, WirelessKeyView.exe will display the wireless network names and associated passwords that are stored in your system.

I encourage you to obtain these tools and run them on your system to reveal how many passwords are stored on your system. If you discover sensitive passwords stored on your system and you allow others to use your system, you will want to ensure that you clean out the stored passwords.

While you might not be able to delete all of the saved passwords, at least you will now have a better handle on all of the passwords stored on your system that are recoverable.

Revenge Hacking

Revenge is a powerful motivator for hacking. Take, for example, the case of Barry Ardolf of Minnesota. Trouble started when Mr. Ardolf was accused by a neighbor of kissing their 4-year boy on the lips. When the parents confronted Mr. Ardolf, he confessed that the accusation was true. Naturally, the parents of the 4-year old contacted the police. This made Mr. Ardolf angry and he decided to seek revenge.

As part of his revenge, court documents indicate that Mr. Ardolf used aircrack, a freely available wireless security tool, to discover the Wired Enhanced Privacy (WEP ) password for his neighbor’s network.  With the neighbor’s WEP password, Mr. Ardolf could use his own computer to connect to the neighbor’s wireless network. Once connected to the wireless network, Mr. Ardolf would be able to access the Internet using the  neighbor’s IP address. Thus, any activity performed by Mr. Ardolf on the Internet would be tracked back to his neighbor’s residence. This provided the opportunity for Mr. Ardolf to take revenge by taking actions that would appear to be done by his neighbor.

Meanwhile, the “hacked” neighbor had been getting reports that coworkers were receiving bizarre email messages that could not be explained. The neighbor had taken the step of bringing in a security consultant to monitor activity on his network. During the time that the monitor was active, the Secret Service investigated an email threat that was found to have been sent from Mr. Ardolf through the neighbor’s wireless network. Since it was sent from “hacked” network, the IP address of the email message came back to the neighbor, not Mr. Ardolf. This lead the Secret Service to visit the neighbor, who turnover over the information from the monitor. In the monitor logs was Mr. Ardolf’s POP3 username and password, presumably known only to Mr. Ardolf. This piece of incriminating information cause the government to turn its attention toward Mr. Ardolf.

The username and password found in the monitor log gave the government probable cause to obtain a search warrant for Mr. Ardolf’s residence. Examination of his computers revealed that he had sent the threatening email, as well as created false email addresses and MySpace accounts designed to appear to be the neighbor.

Further, evidence was uncovered  that Mr. Ardolf had in his possession underage illicit images. He appears to have sent these images from the fake accounts that he created, apparently to “frame” his neighbor.

There are a few lessons that show up from this case. One is that revenge is a powerful and dangerous motivation, one that I covered in my book from a few years ago, High Tech Crimes Revealed.  Revenges is a dangerous motivation since the goal is to damage or hurt another.

Another lesson is that security weaknesses can be used to attack home networks as well as business networks. While WEP encryption is better that no encryption, it suffers from security flaws that can be easily exploited using freely available tools.

In this case, the use of improved WiFi Protect Access (WPA) encryption would have made it more difficult for Mr. Ardolf to break into the neighbor’s wireless network.


Are Macs immune to virus or malware?

A couple of weeks ago, I was asked to check on a Windows-based computer that had recently been infected with a “virus scanner” malware. In this case, the malware (malicious software) would put up a pop up screen that was kind enough to inform you that your computer was loaded with a bunch of virus infections. Further, it offered a link that would allow you to pay for a virus scanner to clean things up, right away. The malware writers made it very difficult for the average user to ignore their malware, as it disabled the buttons that would allow you to close the pop up boxes. Further, it redirected any attempts to run programs such as regedit back to the malware. Cleaning the malware had to be done through Safe-mode.

But, why would I mention this in a posting about Macs and virii? Well, in this case, I was able to track the source of this Windows malware infection back to an email message which contained a series of links to articles that the author thought people would find useful. When the email author, let’s call him Stan, was notified that his email was linked to a malware attack, his response was, quite simply, “That is impossible, because I have a Mac.”

Of course, this is not true. Macs, as good as they are, are not able to scrub malware out of email messages or links on webpages. But, this comment got me thinking, are Macs actually malware free. Dan Moren of Mac World recently released an article entitled “New Mac Trojan horse masquerades as virus scanner“. This articles describes malware written for the Mac that impersonates a virus scanner. Sound familiar?

This is not the first case of the Mac being susceptible to a malware attack. Back in April of 2006, an article from the AP called “Macs no longer immune to viruses, experts say” was released. So, it appears that the Mac has been susceptible to malware for a while.

What Apple has done, it seems,  is taken steps to protect the user environment from malware, as shown in this explanation from Apple. Noteworthy steps include using a sand-box environment and screening the content of downloaded files. So, how did the virus scanner attack affect Macs? Apparently, the malware writers were able find a way around the Mac security and/or screening defenses. It is quite possible that it will happen more often in the future, as Macs continue to become a more popular, more widely used platform and the malware writers become more adept.

So, it appears that Apple has done a lot to secure their user environment, but that malware is still getting through…

how safe is your digital data?

The recent hack of the Sony network has exposed user information on approximately 77 million accounts.  The attack, according to an article in the The Telegraph, has potentially exposed passwords and credit card numbers.  If this is true, this is “not good”, since it would imply that the passwords and the credit card numbers were not encrypted when they were stored in Sony’s network.

I registered for the Sony network, so apparently my credentials were among the ones stolen during this attack. At the end of this posting is the email message that I received from Sony about the incident. (I have removed some information that is not important for this posting.) The posting recommends changing the account password once the Sony network has been reactivated.

The Sony network required an email address and a password for a user to log into their network. An email address along with a password is used for authentication to other networks, such as LinkedIN or Facebook. Thus, it is possible that some of the accounts compromised in the Sony network attack can be used to hijack non Sony accounts. The below email message from Sony would be better if it recommended that users change all accounts using the same email address and/or the same password used in the Sony network.

What can users do? When registering for networks such as Sony’s, Amazon’s or others, be sure the email adress and password used for authenticiation on one site is not used for authentication on other sites. This means that a user needs to  ensure that the userid/password used to log into Facebook is not the same as the userid/password used to log into the Sony network. This will limit the potential risk if one network is compromised For example, my amazon ID is not at risk from this attack since I user different account information for the Amazon and Sony networks.

Here is the email I recieved.

" Valued PlayStation(R)Network/Qriocity Customer:
 We have discovered that between April 17 and April 19, 2011, certain PlayStation Network 
and Qriocity service user account information was compromised in connection with an illegal
and unauthorized intrusion into our network. In response to this intrusion, we have:
 1) Temporarily turned off PlayStation Network and Qriocity services;
 2) Engaged an outside, recognized security firm to conduct a full and complete investigation
into what happened; and
 3) Quickly taken steps to enhance security and strengthen our network infrastructure by rebuilding our system to provide you with greater protection of your personal information.
 We greatly appreciate your patience, understanding and goodwill as we do whatever it takes 
to resolve these issues as quickly and efficiently as practicable.
 Although we are still investigating the details of this incident, we believe that an 
unauthorized person has obtained the following information that you provided: name, address 
(city, state, zip), country, email address, birthdate, PlayStation Network/Qriocity password
and login, and handle/PSN online ID. It is also possible that your profile data, including 
purchase history and billing address (city, state, zip), and your PlayStation 
Network/Qriocity password security answers may have been obtained. If you have authorized a 

sub-account for your dependent, the same data with respect to your dependent may have been 
obtained. While there is no evidence at this time that credit card data was taken, we 
cannot rule out the possibility. If you have provided your credit card data through 
PlayStation Network or Qriocity, out of an abundance of caution we are advising you that 
your credit card number (excluding security code) and expiration date may have been 
... When the PlayStation Network and Qriocity services are fully restored, we strongly 
recommend that you log on and change your password. Additionally, if you use your 
PlayStation Network or Qriocity user name or password for other unrelated services or 
accounts, we strongly recommend that you change them as well.
 To protect against possible identity theft or other financial loss, we encourage you to 
remain vigilant, to review your account statements and to monitor your credit reports. We 
are providing the following information for those who wish to consider it:   
- U.S. residents are entitled under U.S. law to one free credit report annually from each of
 the three major credit bureaus. To order your free credit report, visit 
www.annualcreditreport.com or call toll-free (877) 322-8228.
 - We have also provided names and contact information for the three major U.S. credit 
bureaus below.  At no charge, U.S. residents can have these credit bureaus place a "fraud 
alert" on your file that alerts creditors to take additional steps to verify your identity 
prior to granting credit in your name. This service can make it more difficult for someone 
to get credit in your name. Note, however, that because it tells creditors to follow 
certain procedures to protect you, it also may delay your ability to obtain credit while 
the agency verifies your identity.  As soon as one credit bureau confirms your fraud alert, 
the others are notified to place fraud alerts on your file. Should you wish to place a 
fraud alert, or should you have any questions regarding your credit report, please contact 
any one of the agencies listed below:
  • Experian: 888-397-3742; www.experian.com; P.O. Box 9532, Allen, TX 75013
  • Equifax: 800-525-6285; www.equifax.com; P.O. Box 740241, Atlanta, GA 30374-0241
  • TransUnion: 800-680-7289; www.transunion.com; Fraud Victim Assistance Division, P.O. 
    Box 6790, Fullerton, CA 92834-6790
 - You may wish to visit the website of the U.S. Federal Trade Commission at
 www.consumer.gov/idtheft or reach the FTC at 1-877-382-4357 or 600 Pennsylvania Avenue, 
NW, Washington, DC 20580 for further information about how to protect yourself from 
identity theft. Your state Attorney General may also have advice on preventing identity 
theft, and you should report instances of known or suspected identity theft to law 
enforcement, your State Attorney General, and the FTC. For North Carolina residents, the 
Attorney General can be contacted at 9001 Mail Service Center, Raleigh, NC 27699-9001; 
telephone (877) 566-7226; or www.ncdoj.gov. For Maryland residents, the Attorney General 
can be contacted at 200 St. Paul Place, 16th Floor, Baltimore, MD 21202;
telephone: (888) 743-0023; or www.oag.state.md.us.
 Sony Computer Entertainment and Sony Network Entertainment"

From this message, it appears that the attacker were able to get hold of significant personal information. 

So, what can we do to better protect ourselves? Kkeep in mind that some of the networks that we rely on will be compromised by attackers. Thus, it is the user’s responsibility to ensure that ids are different on each site.

is the day of the virus scanner over?

I have noticed a new trend emerging over the past couple of years… the virus writers are out-pacing the virus detectors. First, consider the clampi/zeus virus which I wrote about in 2009.  This virus was being used to steal banking credentials and was very successful. Of note was that up to date virus scanners were not detecting the clampi virus.

Then, last year, information came to light on the “stuxnet” virus. This virus has recently been “cracked” by Ralph Langner. His presented his findings at TED (see the video here .) The summary of his presentation was that the virus was very advanced and written to attack specific systems involved in the refinement of uranium in Iran. This is the stuff of spy movies.

Note that clampi and stuxnet virii have the following things in common:

  1. they were not detected by virus scanners,
  2. they wanted to be stealth and not damage the host computer,
  3. they were targetted in their attacks.

So, what can we make of this new trend. Virus detection seems to be losing the battle against the truly sophisticated virus writers, and this is not a good trend. As computers contain more sensitive information such as banking records or nuclear secrets, they will become targets of attack. And, since the virus writers are outpacing the virus defenders at the moment, it is difficult to trust any system connected to the Internet, whether it has a virus scanner or not.

One option that might become useful in the future is a computer that runs a virtual operating system, such as VMWare. A virtual operating system loads its operating system from a static image. Though the VMware operating system might get infected with a virus, the virus itself does not infect the static image from which the VMWare is loaded. (At least not yet.) Basically, the virutal operating system is protected from a persistent virus threat since it reloads the operating system with every reboot.

Of course, this means that making real persistent changes to the operating system, such as installing new software, becomes very difficult. So difficult, in fact, that we probably won’t see people using virtual operating systems for a while…

Meanwhile, the search goes on for a better method to protect systems against persistent virus infections.