Entries Tagged "keys"

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Bank Card "Master Key" Stolen

South Africa’s Postbank experienced a catastrophic security failure. The bank’s master PIN key was stolen, forcing it to cancel and replace 12 million bank cards.

The breach resulted from the printing of the bank’s encrypted master key in plain, unencrypted digital language at the Postbank’s old data centre in the Pretoria city centre.

According to a number of internal Postbank reports, which the Sunday Times obtained, the master key was then stolen by employees.

One of the reports said that the cards would cost about R1bn to replace. The master key, a 36-digit code, allows anyone who has it to gain unfettered access to the bank’s systems, and allows them to read and rewrite account balances, and change information and data on any of the bank’s 12-million cards.

The bank lost $3.2 million in fraudulent transactions before the theft was discovered. Replacing all the cards will cost an estimated $58 million.

Posted on June 17, 2020 at 6:21 AMView Comments

Another Intel Speculative Execution Vulnerability

Remember Spectre and Meltdown? Back in early 2018, I wrote:

Spectre and Meltdown are pretty catastrophic vulnerabilities, but they only affect the confidentiality of data. Now that they—and the research into the Intel ME vulnerability—have shown researchers where to look, more is coming—and what they’ll find will be worse than either Spectre or Meltdown. There will be vulnerabilities that will allow attackers to manipulate or delete data across processes, potentially fatal in the computers controlling our cars or implanted medical devices. These will be similarly impossible to fix, and the only strategy will be to throw our devices away and buy new ones.

That has turned out to be true. Here’s a new vulnerability:

On Tuesday, two separate academic teams disclosed two new and distinctive exploits that pierce Intel’s Software Guard eXtension, by far the most sensitive region of the company’s processors.

[…]

The new SGX attacks are known as SGAxe and CrossTalk. Both break into the fortified CPU region using separate side-channel attacks, a class of hack that infers sensitive data by measuring timing differences, power consumption, electromagnetic radiation, sound, or other information from the systems that store it. The assumptions for both attacks are roughly the same. An attacker has already broken the security of the target machine through a software exploit or a malicious virtual machine that compromises the integrity of the system. While that’s a tall bar, it’s precisely the scenario that SGX is supposed to defend against.

Another news article.

Posted on June 11, 2020 at 6:40 AMView Comments

Securing Internet Videoconferencing Apps: Zoom and Others

The NSA just published a survey of video conferencing apps. So did Mozilla.

Zoom is on the good list, with some caveats. The company has done a lot of work addressing previous security concerns. It still has a bit to go on end-to-end encryption. Matthew Green looked at this. Zoom does offer end-to-end encryption if 1) everyone is using a Zoom app, and not logging in to the meeting using a webpage, and 2) the meeting is not being recorded in the cloud. That’s pretty good, but the real worry is where the encryption keys are generated and stored. According to Citizen Lab, the company generates them.

The Zoom transport protocol adds Zoom’s own encryption scheme to RTP in an unusual way. By default, all participants’ audio and video in a Zoom meeting appears to be encrypted and decrypted with a single AES-128 key shared amongst the participants. The AES key appears to be generated and distributed to the meeting’s participants by Zoom servers. Zoom’s encryption and decryption use AES in ECB mode, which is well-understood to be a bad idea, because this mode of encryption preserves patterns in the input.

The algorithm part was just fixed:

AES 256-bit GCM encryption: Zoom is upgrading to the AES 256-bit GCM encryption standard, which offers increased protection of your meeting data in transit and resistance against tampering. This provides confidentiality and integrity assurances on your Zoom Meeting, Zoom Video Webinar, and Zoom Phone data. Zoom 5.0, which is slated for release within the week, supports GCM encryption, and this standard will take effect once all accounts are enabled with GCM. System-wide account enablement will take place on May 30.

There is nothing in Zoom’s latest announcement about key management. So: while the company has done a really good job improving the security and privacy of their platform, there seems to be just one step remaining to fully encrypt the sessions.

The other thing I want Zoom to do is to make the security options necessary to prevent Zoombombing to be made available to users of the free version of that platform. Forcing users to pay for security isn’t a viable option right now.

Finally—I use Zoom all the time. I finished my Harvard class using Zoom; it’s the university standard. I am having Inrupt company meetings on Zoom. I am having professional and personal conferences on Zoom. It’s what everyone has, and the features are really good.

Posted on April 30, 2020 at 10:24 AMView Comments

DNSSEC Keysigning Ceremony Postponed Because of Locked Safe

Interesting collision of real-world and Internet security:

The ceremony sees several trusted internet engineers (a minimum of three and up to seven) from across the world descend on one of two secure locations—one in El Segundo, California, just south of Los Angeles, and the other in Culpeper, Virginia—both in America, every three months.

Once in place, they run through a lengthy series of steps and checks to cryptographically sign the digital key pairs used to secure the internet’s root zone. (Here’s Cloudflare‘s in-depth explanation, and IANA’s PDF step-by-step guide.)

[…]

Only specific named people are allowed to take part in the ceremony, and they have to pass through several layers of security—including doors that can only be opened through fingerprint and retinal scans—before getting in the room where the ceremony takes place.

Staff open up two safes, each roughly one-metre across. One contains a hardware security module that contains the private portion of the KSK. The module is activated, allowing the KSK private key to sign keys, using smart cards assigned to the ceremony participants. These credentials are stored in deposit boxes and tamper-proof bags in the second safe. Each step is checked by everyone else, and the event is livestreamed. Once the ceremony is complete—which takes a few hours—all the pieces are separated, sealed, and put back in the safes inside the secure facility, and everyone leaves.

But during what was apparently a check on the system on Tuesday night—the day before the ceremony planned for 1300 PST (2100 UTC) Wednesday—IANA staff discovered that they couldn’t open one of the two safes. One of the locking mechanisms wouldn’t retract and so the safe stayed stubbornly shut.

As soon as they discovered the problem, everyone involved, including those who had flown in for the occasion, were told that the ceremony was being postponed. Thanks to the complexity of the problem—a jammed safe with critical and sensitive equipment inside—they were told it wasn’t going to be possible to hold the ceremony on the back-up date of Thursday, either.

Posted on February 14, 2020 at 6:07 AMView Comments

New SHA-1 Attack

There’s a new, practical, collision attack against SHA-1:

In this paper, we report the first practical implementation of this attack, and its impact on real-world security with a PGP/GnuPG impersonation attack. We managed to significantly reduce the complexity of collisions attack against SHA-1: on an Nvidia GTX 970, identical-prefix collisions can now be computed with a complexity of 261.2rather than264.7, and chosen-prefix collisions with a complexity of263.4rather than267.1. When renting cheap GPUs, this translates to a cost of 11k US$ for a collision,and 45k US$ for a chosen-prefix collision, within the means of academic researchers.Our actual attack required two months of computations using 900 Nvidia GTX 1060GPUs (we paid 75k US$ because GPU prices were higher, and we wasted some time preparing the attack).

It has practical applications:

We chose the PGP/GnuPG Web of Trust as demonstration of our chosen-prefix collision attack against SHA-1. The Web of Trust is a trust model used for PGP that relies on users signing each other’s identity certificate, instead of using a central PKI. For compatibility reasons the legacy branch of GnuPG (version 1.4) still uses SHA-1 by default for identity certification.

Using our SHA-1 chosen-prefix collision, we have created two PGP keys with different UserIDs and colliding certificates: key B is a legitimate key for Bob (to be signed by the Web of Trust), but the signature can be transferred to key A which is a forged key with Alice’s ID. The signature will still be valid because of the collision, but Bob controls key A with the name of Alice, and signed by a third party. Therefore, he can impersonate Alice and sign any document in her name.

From a news article:

The new attack is significant. While SHA1 has been slowly phased out over the past five years, it remains far from being fully deprecated. It’s still the default hash function for certifying PGP keys in the legacy 1.4 version branch of GnuPG, the open-source successor to PGP application for encrypting email and files. Those SHA1-generated signatures were accepted by the modern GnuPG branch until recently, and were only rejected after the researchers behind the new collision privately reported their results.

Git, the world’s most widely used system for managing software development among multiple people, still relies on SHA1 to ensure data integrity. And many non-Web applications that rely on HTTPS encryption still accept SHA1 certificates. SHA1 is also still allowed for in-protocol signatures in the Transport Layer Security and Secure Shell protocols.

Posted on January 8, 2020 at 9:38 AMView Comments

Chrome Extension Stealing Cryptocurrency Keys and Passwords

A malicious Chrome extension surreptitiously steals Ethereum keys and passwords:

According to Denley, the extension is dangerous to users in two ways. First, any funds (ETH coins and ERC0-based tokens) managed directly inside the extension are at risk.

Denley says that the extension sends the private keys of all wallets created or managed through its interface to a third-party website located at erc20wallet[.]tk.

Second, the extension also actively injects malicious JavaScript code when users navigate to five well-known and popular cryptocurrency management platforms. This code steals login credentials and private keys, data that it’s sent to the same erc20wallet[.]tk third-party website.

Another example of how blockchain requires many single points of trust in order to be secure.

Posted on January 3, 2020 at 6:09 AMView Comments

TPM-Fail Attacks Against Cryptographic Coprocessors

Really interesting research: TPM-FAIL: TPM meets Timing and Lattice Attacks, by Daniel Moghimi, Berk Sunar, Thomas Eisenbarth, and Nadia Heninger.

Abstract: Trusted Platform Module (TPM) serves as a hardware-based root of trust that protects cryptographic keys from privileged system and physical adversaries. In this work, we per-form a black-box timing analysis of TPM 2.0 devices deployed on commodity computers. Our analysis reveals that some of these devices feature secret-dependent execution times during signature generation based on elliptic curves. In particular, we discovered timing leakage on an Intel firmware-based TPM as well as a hardware TPM. We show how this information allows an attacker to apply lattice techniques to recover 256-bit private keys for ECDSA and ECSchnorr signatures. On Intel fTPM, our key recovery succeeds after about1,300 observations and in less than two minutes. Similarly, we extract the private ECDSA key from a hardware TPM manufactured by STMicroelectronics, which is certified at CommonCriteria (CC) EAL 4+, after fewer than 40,000 observations. We further highlight the impact of these vulnerabilities by demonstrating a remote attack against a StrongSwan IPsecVPN that uses a TPM to generate the digital signatures for authentication. In this attack, the remote client recovers the server’s private authentication key by timing only 45,000 authentication handshakes via a network connection.

The vulnerabilities we have uncovered emphasize the difficulty of correctly implementing known constant-time techniques, and show the importance of evolutionary testing and transparent evaluation of cryptographic implementations.Even certified devices that claim resistance against attacks require additional scrutiny by the community and industry, as we learn more about these attacks.

These are real attacks, and take between 4-20 minutes to extract the key. Intel has a firmware update.

Attack website. News articles. Boing Boing post. Slashdot thread.

Posted on November 15, 2019 at 9:36 AMView Comments

NordVPN Breached

There was a successful attack against NordVPN:

Based on the command log, another of the leaked secret keys appeared to secure a private certificate authority that NordVPN used to issue digital certificates. Those certificates might be issued for other servers in NordVPN’s network or for a variety of other sensitive purposes. The name of the third certificate suggested it could also have been used for many different sensitive purposes, including securing the server that was compromised in the breach.

The revelations came as evidence surfaced suggesting that two rival VPN services, TorGuard and VikingVPN, also experienced breaches that leaked encryption keys. In a statement, TorGuard said a secret key for a transport layer security certificate for *.torguardvpnaccess.com was stolen. The theft happened in a 2017 server breach. The stolen data related to a squid proxy certificate.

TorGuard officials said on Twitter that the private key was not on the affected server and that attackers “could do nothing with those keys.” Monday’s statement went on to say TorGuard didn’t remove the compromised server until early 2018. TorGuard also said it learned of VPN breaches last May, “and in a related development we filed a legal complaint against NordVPN.”

The breach happened nineteen months ago, but the company is only just disclosing it to the public. We don’t know exactly what was stolen and how it affects VPN security. More details are needed.

VPNs are a shadowy world. We use them to protect our Internet traffic when we’re on a network we don’t trust, but we’re forced to trust the VPN instead. Recommendations are hard. NordVPN’s website says that the company is based in Panama. Do we have any reason to trust it at all?

I’m curious what VPNs others use, and why they should be believed to be trustworthy.

Posted on October 23, 2019 at 6:15 AMView Comments

Crown Sterling Claims to Factor RSA Keylengths First Factored Twenty Years Ago

Earlier this month, I made fun of a company called Crown Sterling, for…for…for being a company that deserves being made fun of.

This morning, the company announced that they “decrypted two 256-bit asymmetric public keys in approximately 50 seconds from a standard laptop computer.” Really. They did. This keylength is so small it has never been considered secure. It was too small to be part of the RSA Factoring Challenge when it was introduced in 1991. In 1977, when Ron Rivest, Adi Shamir, and Len Adelman first described RSA, they included a challenge with a 426-bit key. (It was factored in 1994.)

The press release goes on: “Crown Sterling also announced the consistent decryption of 512-bit asymmetric public key in as little as five hours also using standard computing.” They didn’t demonstrate it, but if they’re right they’ve matched a factoring record set in 1999. Five hours is significantly less than the 5.2 months it took in 1999, but slower than would be expected if Crown Sterling just used the 1999 techniques with modern CPUs and networks.

Is anyone taking this company seriously anymore? I honestly wouldn’t be surprised if this was a hoax press release. It’s not currently on the company’s website. (And, if it is a hoax, I apologize to Crown Sterling. I’ll post a retraction as soon as I hear from you.)

EDITED TO ADD: First, the press release is real. And second, I forgot to include the quote from CEO Robert Grant: “Today’s decryptions demonstrate the vulnerabilities associated with the current encryption paradigm. We have clearly demonstrated the problem which also extends to larger keys.”

People, this isn’t hard. Find an RSA Factoring Challenge number that hasn’t been factored yet and factor it. Once you do, the entire world will take you seriously. Until you do, no one will. And, bonus, you won’t have to reveal your super-secret world-destabilizing cryptanalytic techniques.

EDITED TO ADD (9/21): Others are laughing at this, too.

EDITED TO ADD (9/24): More commentary.

EDITED TO ADD (10/9): There’s video of the “demo.” And some history of Crown Sterling’s CEO Robert Grant.

Posted on September 20, 2019 at 12:50 PMView Comments

Sidebar photo of Bruce Schneier by Joe MacInnis.