Category: Cryptography

Feb 28 2014

Tor to Release Instant Messaging Bundle (TIMB)

Tor Instant Messaging BundleThe TOR project is about to join the world of secure instant messaging, laying out a roadmap that would see its first code for a new project delivered by the end of March 2014.

The first aim of the Tor Instant Messaging Bundle will be to get experimental builds happening with Instantbird providing the messaging interface.

As explained, Instantbird was considered to be the best of the three messaging platforms considered by the TOR people. Pidgin/libpurple and xmpp-client were also looked at but didn’t make the cut.

The developers’ “mild preference” for Instantbird is tempered by a couple of open questions. One is what attack profile it presents to the outside world; the other, its OTR support, is being addressed by the TOR developers. Libpurple, which is currenly an Instantbird dependency, is being removed.

As this document notes, the group also plans to have the Tor Instant Messaging Bundle audited so “people in countries where communication for the purpose of activism is met with intimidation, violence, and prosecution will be able to avoid the scrutiny of criminal cartels, corrupt officials, and authoritarian governments.”

With Facebook’s recent US$16bn takeover of the messaging service that has more than 450m monthly users, some of the more worried corners of the online communities have questioned the move and whether this will mean their messages will become more susceptible to being monitored, something Facebook has been accused of in the past.

That is why Tor has timed its announcement perfectly!

Dec 25 2013

4096-bit RSA Key Extraction Attack via Acoustic Cryptanalysis

A trio of scientists have verified that results they first presented nearly 10 years ago are in fact valid, proving that they can extract a 4096-bit RSA key from a laptop using an acoustic side-channel attack that enables them to record the noise coming from the laptop during decryption, using a smartphone placed nearby. The attack, laid out in a new paper, can be used to reveal a large RSA key in less than an hour.

Acoustic Cryptanalysis
Parabolic microphone extracting an RSA key from a target laptop

The attack relies on a number of factors, including proximity to the machine performing the decryption operation and being able to develop chosen ciphertexts that incite certain observable numerical cancellations in the GnuPG algorithm. Over several thousand repetitions of the algorithm’s operation, the researchers discovered that there was sound leakage they could record over the course of fractions of a second and interpret, resulting in the discovery of the RSA key in use.

Their attack works against a number of laptop models and they said that there are a number of ways that they could implement it, including through a malicious smartphone app running on a device near a target machine. They could also implement it through software on a compromised mobile device of through the kind of eavesdropping bugs used by intelligence agencies and private investigators.

The developers of GnuPG have developed a patch for the vulnerability that the Israeli researchers used, implementing a technique known as blinding. The patch is included in version 1.4.16 of GnuPG. Shamir and his co-authors, Daniel Genkin and Eran Tromer, said that they also could perform their attack from a greater distance using a parabolic microphone and may also work with a laser microphone or vibrometer.

Research Paper: RSA Key Extraction via Low-Bandwidth Acoustic Cryptanalysis

Jun 26 2012

Crack RSA SecurID 800 Secret Key in 13 Minutes

RSA SecurID 800RSA’s SecurID 800 is one of at least five commercially available security devices susceptible to a new attack that extracts cryptographic keys used to log in to sensitive corporate and government networks.

Scientists have devised an attack that takes only minutes to steal the sensitive cryptographic keys stored on a raft of hardened security devices that corporations and government organizations use to access networks, encrypt hard drives, and digitally sign e-mails.

The exploit, described in a paper to be presented at the CRYPTO 2012 conference in August, requires just 13 minutes to extract a secret key from RSA’s SecurID 800, which company marketers hold out as a secure way for employees to store credentials needed to access confidential virtual private networks, corporate domains, and other sensitive environments. The attack also works against other widely used devices, including the electronic identification cards the government of Estonia requires all citizens 15 years or older to carry, as well as tokens made by a variety of other companies.

“They’re designed specifically to deal with the case where somebody gets physical access to it or takes control of a computer that has access to it, and they’re still supposed to hang onto their secrets and be secure,” Matthew Green, a professor specializing in cryptography in the computer science department at Johns Hopkins University, told Ars. “Here, if the malware is very smart, it can actually extract the keys out of the token. That’s why it’s dangerous.” Green has blogged about the attack here.

It’s this version of the attack the scientists used to extract secret keys stored on RSA’s SecurID 800 and many other devices that use PKCS#11, a programming interface included in a wide variety of commercial cryptographic devices. Under the attack Bleichenbacher devised, it took attackers about 215,000 oracle calls on average to pierce a 1024-bit cryptographic wrapper. That required enough overhead to prevent the attack from posing a practical threat against such devices. By modifying the algorithm used in the original attack, the revised method reduced the number of calls to just 9,400, requiring only about 13 minutes of queries, Green said.

Other devices that store RSA keys that are vulnerable to the same attack include the Aladdin eTokenPro and iKey 2032 made by SafeNet, the CyberFlex manufactured by Gemalto, and Siemens’ CardOS, according to the paper.

Nov 30 2011

BozoCrack – MD5 Password Hash Cracker

BozoCrack is a depressingly effective MD5 password hash cracker with almost zero CPU/GPU load. Instead of rainbow tables, dictionaries, or brute force, BozoCrack simply finds the plaintext password. Specifically, it googles the MD5 hash and hopes the plaintext appears somewhere on the first page of results.

It works way better than it ever should.

How?
Basic usage:

$ ruby bozocrack.rb my_md5_hashes.txt

The input file has no specified format. BozoCrack automatically picks up strings that look like MD5 hashes. A single line shouldn’t contain more than one hash.

Example with output:

$ ruby bozocrack.rb example.txt
Loaded 5 unique hashes
fcf1eed8596699624167416a1e7e122e:octopus
bed128365216c019988915ed3add75fb:passw0rd
d0763edaa9d9bd2a9516280e9044d885:monkey
dfd8c10c1b9b58c8bf102225ae3be9eb:12081977
ede6b50e7b5826fe48fc1f0fe772c48f:1q2w3e4r5t6y

Why?
To show just how bad an idea it is to use plain MD5 as a password hashing mechanism. Honestly, if the passwords can be cracked with this software, there are no excuses.

Who?
BozoCrack was written by Juuso Salonen

Download: bozocrack.rb

Sep 20 2011

Hackers Break SSL Encryption

SSL BreaksResearchers have discovered a serious weakness in virtually all websites protected by the secure sockets layer protocol that allows attackers to silently decrypt data that’s passing between a webserver and an end-user browser.

The vulnerability resides in versions 1.0 and earlier of TLS, or transport layer security, the successor to the secure sockets layer technology that serves as the internet’s foundation of trust. Although versions 1.1 and 1.2 of TLS aren’t susceptible, they remain almost entirely unsupported in browsers and websites alike, making encrypted transactions on PayPal, GMail, and just about every other website vulnerable to eavesdropping by hackers who are able to control the connection between the end user and the website he’s visiting.

At the Ekoparty security conference in Buenos Aires later this week, researchers Thai Duong and Juliano Rizzo plan to demonstrate proof-of-concept code called BEAST, which is short for Browser Exploit Against SSL/TLS. The stealthy piece of JavaScript works with a network sniffer to decrypt encrypted cookies a targeted website uses to grant access to restricted user accounts. The exploit works even against sites that use HSTS, or HTTP Strict Transport Security, which prevents certain pages from loading unless they’re protected by SSL.

The demo will decrypt an authentication cookie used to access a PayPal account, Duong said. Two days after this article was first published, Google released a developer version of its Chrome browser designed to thwart the attack.