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Archive for the ‘Cryptography’ Category

Security researchers on Friday unveiled an open-source device that captures the traffic of a wide variety of wireless devices, including keyboards, medical devices, and remote controls.

Keykeriki version 2 captures the entire data stream sent between wireless devices using a popular series of chips made by Norway-based Nordic Semiconductor. That includes the device addresses and the raw payload being sent between them. The open-source package was developed by researchers of Switzerland-based Dreamlab Technologies and includes complete software, firmware, and schematics for building the $100 sniffer.

Keykeriki not only allows researchers or attackers to capture the entire layer 2 frames, it also allows them to send their own unauthorized payloads. That means devices that don’t encrypt communications - or don’t encrypt them properly - can be forced to cough up sensitive communications or be forced to execute rogue commands.

At the CanSecWest conference in Vancouver, Dreamlab Senior Security Expert Thorsten Schroder demonstrated how Keykeriki could be used to attack wireless keyboards sold by Microsoft. The exploit worked because communications in the devices are protected by a weak form of encryption known as xor, which is trivial to break. As a result, he was able to intercept keyboard strokes as they were typed and to remotely send input that executed commands on the attached computer.

“Microsoft made it easy for us because they used their own proprietary crypto,” Schroder said. “Xor is not a very proper way to secure data.”

Even when devices employ strong cryptography, Schroder said Keykeriki may still be able to remotely send unauthorized commands using a technique known as a replay attack, in which commands sent previously are recorded and then sent again.

The device can also be used to spot weaknesses in cryptographic communications by comparing keystrokes to corresponding ciphertext. His analysis shows wireless keyboards made by Logitech most likely use 128-bit AES encryption. But even so, it may still be possible to decipher the contents by exploiting the way the secret key is exchanged.

“We still didn’t figure out how to crack that one, but I think it’s just a matter of time,” he said.

Credit: The Register

Catalogue firm Argos has been criticised for an email security breach that exposed customers’ credit card details and CCV security numbers. The breach was discovered by UK Argos customer Tony Graham and first reported by PC Pro. Graham’s card details were recently fraudulently misused, but this incident has not been linked to the Argos email slip-up.

The exposure came to light after an Argos customer who checked his order confirmation email found that his credit card number and security code was buried in the HTML source of the message. The slip-up meant that any miscreants who intercepted email confirmation messages from Argos would be able to harvest plastic card payment details - if they spotted where the numbers were stashed.

It’s unclear how long the exposure problem lasted, or how many Argos customers were affected.

In a statement, Argos said it had already corrected the fault and was working with privacy watchdogs at the Information Commissioner’s Office in dealing with the fallout from the breach.

Argos takes the security of its customers’ data extremely seriously, is fully aware of the requirements of the Data Protection Act and has taken remedial action in relation to this matter.

We are in contact with the Information Commissioner’s Office. We have made them aware of our approach to customer communications and will continue to work closely with them to ensure we are taking all appropriate actions.

Ed Rowley, product manager EMEA at content security firm M86 Security, said the whole incident might easily have been prevented. “It is incomprehensible that this credit card data was sent out in an unencrypted format - even if the sensitive information was not visible in the main body it should have been protected from being sent out,” he said.

“A good email content filtering product could have enforced encryption or blocked this data from being sent out at all by Argos, using standard or default email security rules.

“This case highlights the need to filter both inbound and outbound email in order to guard against malware coming in but also to block sensitive information from leaking out. It’s astonishing that larger companies are not using these well established security tools and procedures.”

Credit: The Register

Cryptographers have broken the proprietary encryption used to prevent eavesdropping on more than 800 million cordless phones worldwide, demonstrating once again the risks of relying on obscure technologies to remain secure.

The attack is the first to crack the cipher at the heart of the DECT, or Digital Enhanced Cordless Telecommunications, standard, which encrypts radio signals as they travel between cordless phones in homes and businesses and corresponding base stations. A previous hack, by contrast, merely exploited weaknesses in the way the algorithm was implemented.

The fatal flaw in the DECT Standard Cipher is its insufficient amount of “pre-ciphering,” which is the encryption equivalent of shaking a cup of dice to make sure they generate unpredictable results. Because the algorithm discards only the first 40 or 80 bits during the encryption process, it’s possible to deduce the secret key after collecting and analyzing enough of the protected conversation.

“This standard, as with everything else we have broken, has been designed some 20 years ago, and it is proprietary encryption,” said Karsten Nohl, one of the cryptographers who helped devise the attack. “It relied on the fact that the encryption was unknown and hence could not be broken. This is a case where something that has some potential for being strong is broken by just this one design decision that in any public review would have been spotted immediately.”

Nohl, 28, is the same University of Virginia microscope-wielding reverse engineer to crack the encryption in the world’s most widely used smartcard. In December, he struck again after devising a practical attack for eavesdropping on cellphone calls.

He and fellow researchers Erik Tews of the Darmstadt University of Technology and Ralf-Philipp Weinmann of the University of Luxembourg, plan to present their findings Monday at the 2010 Fast Software Encryption workshop in Korea.

Like several of Nohl’s previous hacks, it began with nitric acid and an electron microscope. After dissolving away the epoxy on the silicon chip and then shaving down and magnifying the section dedicated to the DECT encryption, he was able to glean key insights into the underlying algorithm. He then compared the findings against details selectively laid out in a patent and exposed during a debug process.

The results of all three probe methods revealed the fatally insufficient amount of pre-ciphering in the DECT Standard Cipher.

In practical terms, the attack works by collecting bits of the encrypted data stream with known unencrypted contents. In cordless phones, this often comes from a device’s control channel, which broadcasts a variety of predictable data, including call duration and button responses. Sniffing an encrypted conversation with a USRP antenna and the average PC, an attacker would need to collect about four hours of data to break the key in typical scenarios.

In others - such as where DECT is used in restaurants and bars to wirelessly zap payment card details - the time needed to crack the key could be dramatically shorter, Nohl said. The time can also be sped up in a variety of other ways, including by adding certain types of graphics cards to beef up the power of the attacking PC. In some cases, the attack can retrieve the secret key in 10 minutes.

“We expect that some smarter cryptographers than ourselves will find better attacks, of course. We found the algorithm and then implemented the first attack. It’s almost guaranteed that this is not the best attack.”

The DECT Forum, the international body that oversees the standard, said it takes the attack scenarios laid out in the paper seriously and “continues to investigate their applicability.”

The crack of DECT is only the latest time Nohl has defeated the proprietary encryption of a device with critical mass. His 2008 attack on the Mifare Classic smartcard used similar techniques of filing down a silicon chip and then tracing the connections between transistors. His proposed attack of GSM encryption affects cellphones used by more than 800 carriers in 219 countries.

Credit: The Register

Yet another domino in the RSA encryption scheme has fallen with the announcement Thursday that cryptographers have broken 768-bit keys using the widely used public-key algorithm.

An international team of mathematicians, computer scientists and cryptographers broke the key though NFS, or number field sieve, which allowed them to deduce two prime numbers that when multiplied together generated a number with 768 bits. The discovery, which took about two-and-a-half years and hundreds of general-purpose computers, means 768-bit RSA keys can no longer be counted on to encrypt or authenticate sensitive communications.

More importantly, it means it’s only a matter of another decade or so - sooner assuming there’s some sort of breakthrough in NFS or some other form of mathematical factoring - until the next largest RSA key size, at 1024 bits, is similarly cracked. The accomplishment was reached on December 12.

“It’s an important milestone,” said Benjamin Jun, vice president of technology at security consultancy Cryptography Research. “There’s indisputable evidence here that 768-bit key are not enough. It’s a pretty interesting way to close out a decade.”

The team managed to factor the 232-digit number that RSA held out as a representative 768-bit modulus from a now-obsolete challenge. They spent half a year using 80 processors on polynomial selection. Sieving took almost two years and was done on “many hundreds of machines.” Using a single-core 2.2GHz AMD Opteron with 2GB RAM, sieving would have taken about 1,500 years, they estimated.

Factoring the 768-bit key was “several thousand times harder” than factoring a 512-bit one, a feat that was first performed in 1999. By contrast, factoring a 1024-bit RSA modulus, will be about 1,000 times harder than this most recent milestone. That’s more than five times easier than a 768-bit RSA modulus looked just a decade ago.

“If we are optimistic, it may be possible to factor a 1024-bit RSA modulus within the next decade by means of an academic effort on the same limited scale as the effort presented here,” authors of the research wrote. “From a practical security point of view this is not a big deal, given that standards recommend phasing out such moduli by the end of the year 2010.”

But Nate Lawson, a cryptographer who is principal of security consultancy Root Labs, said smaller keys continue to be used for a variety of purposes, often by smaller embedded devices that don’t have the processing power to handle larger keys.

The research team includes Thorsten Kleinjung, Arjen K. Lenstra, Joppe W. Bos and Dag Arne Osvik of EPFL IC LACAL, in Lausanne, Switzerland; Kazumaro Aoki of NTT, in Tokyo; Jens Franke of the University of Bonn’s Department of Mathematics; Emmanuel Thomé, Pierrick Gaudry, Alexander Kruppa and and Paul Zimmermann of INRIA CNRS LORIA, in Cedex, France; and Peter L. Montgomery, Herman te Riele and Andrey Timofeev of Microsoft. A PDF of their paper is at http://eprint.iacr.org/2010/006.pdf

Credit: The Register

The unveiling of a GSM (Global System for Mobile Communications) encryption codebook compiled by a German security researcher and his team of collaborators lowers the bar significantly for the amount of money and technical expertise required to listen in on a GSM-based mobile phone call. More importantly, it illustrates just how old the current GSM encryption is and demonstrates why it’s time for an upgrade.

Law enforcement officials and well-financed cyber criminals have been able to crack GSM encryption for sometime, but the investment was so high that it didn’t pose much of a threat. This new method lowers the price of entry to the point that it is more of an issue, but still not a high risk.

Karsten Nohl announced that he and his team have compiled 2 terabytes worth of GSM encryption data. PC World’s Robert McMillan explains that the results are like “cracking tables that can be used as a kind of reverse phone-book to determine the encryption key used to secure a GSM (Global System for Mobile communications) telephone conversation or text message.”

GSM is the most widely-used mobile phone technology in the world–accounting for over 80 percent of the world’s 4.3 billion mobile phones. The encryption algorithm that protects GSM-based calls from being intercepted and eavesdropped is more than twenty years old, though.

Time is the enemy of encryption. When a new encryption algorithm is developed and claimed to be impenetrable, or that cracking it is so impractical as to not be plausible, those claims are based on current technology. As technology improves, the mainstream consumer computers of tomorrow eventually have the processing capacity of yesterday’s mainframes and suddenly the processing power required to crack the encryption becomes trivial.

As an analogy, think of encryption like a jigsaw puzzle where you have to find one specific puzzle piece. If the puzzle only has 25 pieces, it won’t take you too long to accomplish. That is like a weak encryption algorithm. However, if the puzzle has 10,000 pieces it will take significantly longer.

As time goes on, though, you gather more people to join in the process and develop new strategies to sift through the pieces faster and compress the time required to look through the 10,000 pieces. That is similar to the way difficult encryption algorithms eventually become simple to crack.

There is also always the possibility of a lucky guess. The encryption cracking estimates are based on the amount of time it would take to work through every possible combination and permutation of characters to determine the encryption key. But, you could theoretically find the right key on the eighth try rather than the ten thousandth.

The fact that the A5/1 algorithm used to encrypt GSM handsets is more than two decades old and still chugging along is a testament to the strength the algorithm had at its inception. The mobile phone industry should consider itself lucky that this is only now becoming an issue.

For now, the methods revealed at the Chaos Communication Conference in Berlin still require a fairly hefty investment in technology likely to discourage any casual GSM hacking. But, the mobile phone industry as a whole needs to address the weakness of the geriatric A5/1 encryption algorithm before breaking it becomes so trivial that the encryption is completely useless.

Credit: PCworld

Researchers have uncovered a weakness in the internet’s digital certificate system that allows them to forge counterfeit credentials needed to impersonate virtually any website that relies on the widely used security measure. Using more than 200 PlayStation 3 game consoles, the researchers are able to create a secure sockets layer certificate for any website of their choosing. The forged certificate causes all the major browsers to display a message indicating the website the user is visiting is legitimate because it’s been vetted by a trusted certificate authority using supposedly robust cryptographic measures.

Such attacks could make it easier for phishers to impersonate the sites of banks and other sensitive online services. The findings were presented Tuesday at the 25th annual Chaos Communication Congress in Berlin by researchers from Centrum Wiskunde & Informatica (CWI) in the Netherlands, EPFL in Switzerland, Eindhoven University of Technology (TU/e) in the Netherlands and independent labs in California.

The attack is based on known weaknesses in the cryptographic hash function known as MD5. In 2004, researchers from China showed it was possible to generate the same MD5 fingerprint for two different messages using off-the-shelf computer hardware. Three years later, a separate group of researchers - many who participated in Tuesday’s presentation in Berlin - built off of those findings by showing how to have almost complete freedom in the choice of both messages.

The latest findings take the known MD5 weaknesses a step further by showing how so-called collisions allow for the creation of valid digital credentials used by certificate authorities, which are appointed organizations that validate the authenticity of websites used for banking and other sensitive online activities. Once the researchers have generated the rogue certificate authority certificate, they can create SSL certificates for any site that will be accepted by just about any web-connecting device.

The vulnerability in the web’s SSL system is made possible by a handful of certificate authorities who continue to rely solely on MD5 to sign certificates. Even though the number amounts to a tiny fraction of authorities, all web browsers continue to accept MD5 hashes. The researchers didn’t identify the certificate authorities by name.

The researchers began their proof-of-concept attack with more than 200 PlayStation 3 consoles running in a Linux cluster, which they used to generate millions of possible certificates. Once they found a pair that had a special collision in the MD5 hash, they requested a legitimate website certificate from one of the authorities that relies only on MD5 to generate signatures.

After copying the signature into a rogue certificate authority credential, they had the ability to generate widely accepted website certificates for any site of their choosing.

To prevent misuse of their certificate, they set it to expire in 2004, so only machines that are badly out of date can be tricked by their attack. Still, Appelbaum says, it should now be clear that MD5 is irretrievably broken and can no longer be trusted.

Credit: The Register

A security researcher with Canola & Jones, Rodney Thayer, uncovered flaws in the encryption certificates used to protect the websites of hospitals, banks, and even top-secret government spy agencies, in his research. The founding raising questions about compliance with regulations requiring them to adequately safeguard their online visitors.

Security sockets layer (SSL) was developed in the mid 1990s as a measure to prevent websites that transact commerce or other sensitive business from being spoofed by attackers intent on defrauding visitors. It uses cryptographic certificates that mathematically validate that the site is operated by a particularly company or organization.

Using search queries typed into Google, the researcher found 31 sites maintained by the US Central Intelligence Agency, NASA, the World Bank, and Fortune 500 companies that used flawed security sockets layer certificates for authentication.

Among flawed sites there was a page for partner accounts offered by technology website CNET and an application page offered by Gartner, a company that dispenses advice on a host of security issues. Other organizations using defective certificates included the US Computer Emergency Readiness Team, Advanced Micro Devices, Intuit, Google, Mercedes Benz, Adobe and Microsoft.

In many cases, the certs identified by Thayer have expired. In other cases, they use an insecure version known as SSL 2, an obsolete algorithm known as 40-bit RC-4 or certificates that are misc-configured. In some cases, the dysfunctional forms accompany web addresses that webmasters long abandoned. This may seem innocuous, but Thayer warns they can erode security by training users to ignore security warnings automatically generated by web browsers.

SSL “suffers from the fact that it’s one of the exotic technologies that we all had to get working for the whole internet .com thing to happen,” Thayer says. “Everybody basically for the last 5 years at least who’s done this was just following a check list that got handed, so nobody’s really been thinking of this as a security issue.”

The Federal Information Processing Standards require federal agencies to use valid SSL certificates for webpages that accept employee logins. The Health Insurance Portability and Accountability Act and Payment Card Industry rules place similar requirements on health care providers and online merchants.

Credit: The Register

A new version of Gpcode, which was recently discovered, uses a complex encryption algorithm to encrypt user files, making it impossible to open them. The files that might be encrypted by this virus are .doc, .txt, .pdf, .xls, .jpg, .png, .cpp, .h and some others. Encrypted files original name will remain but a suffix “._CRYPT” will be added to each file. It also drops a file called “!_READ_ME_!.txt” onto the same folder with encrypted files, which contains the following text:

“Your files are encrypted with RSA-1024 algorithm. To recovery your files you need to buy our decryptor. To buy decrypting tool contact us at: ********@yahoo.com”

Files encrypted by previous versions of Gpcode were possible to decrypt. In the past, signatures for Virus.Win32.Gpcode.ai have been added to the Kaspersky Anti-Virus databases. This time quick and painless decryption should be impossible, since Kaspersky analysts confirmed a strong 1024 bit encryption that can not be decrypted without the original key.

Kaspersky Lab offers affected users to contact them at stopgpcode@kaspersky.com by using another PC in case of this particular infection. Users who did not reboot or turn off their infected PC, who can tell what did they do before the infection occurred and who can tell the exact infection time and date, will be helped and Kaspersky Lab promises to do everything they can to restore the encrypted files.

If your files have been encrypted by Gpcode, Kaspersky Lab strongly recommends that you should not pay money to the creators of this virus, as this will encourage further crime. There is also no guaranty you will receive the decryption key after payment.