A Geek With Guns

Chronicling the depravities of the State.

Archive for the ‘Security’ tag

Avoid E-Mail for Security Communications

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The Pretty Good Privacy (PGP) protocol was created to provide a means to securely communicate via e-mail. Unfortunately, it was a bandage applied to a protocol that has only increased significantly in complexity since PGP was released. The ad-hoc nature of PGP combined with the increasing complexity of e-mail itself has lead to rather unfortunate implementation failures that have left PGP users vulnerable. A newly released attack enables attackers to spoof PGP signatures:

Digital signatures are used to prove the source of an encrypted message, data backup, or software update. Typically, the source must use a private encryption key to cause an application to show that a message or file is signed. But a series of vulnerabilities dubbed SigSpoof makes it possible in certain cases for attackers to fake signatures with nothing more than someone’s public key or key ID, both of which are often published online. The spoofed email shown at the top of this post can’t be detected as malicious without doing forensic analysis that’s beyond the ability of many users.

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The spoofing works by hiding metadata in an encrypted email or other message in a way that causes applications to treat it as if it were the result of a signature-verification operation. Applications such as Enigmail and GPGTools then cause email clients such as Thunderbird or Apple Mail to falsely show that an email was cryptographically signed by someone chosen by the attacker. All that’s required to spoof a signature is to have a public key or key ID.

The good news is that many PGP plugins have been updated to patch this vulnerability. The bad news is that this is the second major vulnerability found in PGP in the span of about a month. It’s likely that other major vulnerabilities will be discovered in the near future since the protocol appears to be receiving a lot of attention.

PGP is suffering from the same fate as most attempts to bolt security onto insecure protocols. This is why I urge people to utilize secure communication technology that was designed from the start to be secure and has been audited. While there are no guarantees in life, protocols that were designed from the ground up with security in mind tend to fair better than protocols that were bolted on after the fact. Of course designs can be garbage, which is where an audit comes in. The reason you want to rely on a secure communication tool only after it has been audited is because an audit by an independent third-party can verify that the tool is well designed and provides effective security. And audit isn’t a magic bullet, unfortunately those don’t exist, but it allows you to be reasonably sure that the tool you’re using isn’t complete garbage.

Written by Christopher Burg

June 15th, 2018 at 10:00 am

When Your Smart Lock Isn’t Smart

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My biggest gripe with so-called smart products is that they tend to not be very smart. For example, the idea of a padlock that can be unlocked with your phone isn’t a bad idea in of itself. It would certainly be convenient since most people carry a smartphone these days. However, if it’s designed by people who paid no attention to security, the lock quickly because convenient for unauthorized parties as well:

Yes. The only thing we need to unlock the lock is to know the BLE MAC address. The BLE MAC address that is broadcast by the lock.

I was so astounded by how bad the security was that I ordered another and emailed Tapplock to check the lock and app were genuine.

I scripted the attack up to scan for Tapplocks and unlock them. You can just walk up to any Tapplock and unlock it in under 2s. It requires no skill or knowledge to do this.

I wish that this was one of those findings that is so rare that it’s newsworthy. Unfortunately, a total lack of interest in security seems to be a defining characteristic for developers of “smart” products. While this lack of awareness isn’t unexpected for a company developing, say, a smart thermostat (after all, I wouldn’t expect somebody who is knowledgeable about thermostats to necessarily be an expert in security as well), it’s an entirely different matter when the product being developed is itself a security product.

The problem with this attack is how trivial it is to perform. The author of the article notes that they’re porting the script they developed to unlock these “smart” locks to Android. Once the attack is available for smartphones, anybody can potentially unlock any of these locks with a literal tap of a button. This makes them even easier to bypass than those cheap Masterlock padlocks that are notorious for being insecure.

Written by Christopher Burg

June 14th, 2018 at 11:00 am

You Must Guard Your Own Privacy

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People often make the mistake of believing that they can control the privacy for content they post online. It’s easy to see why they fall into this trap. Facebook and YouTube both offer privacy controls. Facebook along with Twitter also provide private messaging. However, online privacy settings are only as good as the provider makes them:

Facebook disclosed a new privacy blunder on Thursday in a statement that said the site accidentally made the posts of 14 million users public even when they designated the posts to be shared with only a limited number of contacts.

The mixup was the result of a bug that automatically suggested posts be set to public, meaning the posts could be viewed by anyone, including people not logged on to Facebook. As a result, from May 18 to May 27, as many as 14 million users who intended posts to be available only to select individuals were, in fact, accessible to anyone on the Internet.

Oops.

Slip ups like this are more common than most people probably realize. Writing software is hard. Writing complex software used by billions of people is really hard. Then after the software is written, it must be administered. Administering complex software used by billions of people is also extremely difficult. Programmers and administrators are bound to make mistakes. When they do, the “confidential” content you posted online can quickly become publicly accessible.

Privacy is like anything else, if you want the job done well, you need to do it yourself. The reason services like Facebook can accidentally make your “private” content public is because they have complete access to your content. If you want to have some semblance of control over your privacy, your content must only be accessible to you. If you want that content to be available to others, you must post it in such a way where only you and them can access it.

This is the problem that public key cryptography attempts to solve. With public key cryptography each person has a private and public key. Anything encrypted with the public key can only be decrypted with the private key. Needless to say, as the names implies, you can post your public key to the Internet but must guard the security of your private key. When you want to make material available to somebody else, you encrypt it with their public key so hey can decrypted it with their private key. Likewise, when they want to make content available to you they must encrypt it with your public key so you can decrypt it with your private key. This setup gives you the best ability to enforce privacy controls because, assuming no party’s private key has been compromised, only specifically authorized parties have access to content. Granted, there are still a lot of ways for this setup to fall apart but a simple bad configuration isn’t going to suddenly make millions of people’s content publicly accessible.

Written by Christopher Burg

June 8th, 2018 at 10:30 am

EFAIL

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A vulnerability was announced yesterday that affects both OpenPGP and S/MIME encrypted e-mails. While this was initially being passed off as an apocalyptic discovery, I don’t think that it’s scope is quite as bad as many are claiming. First, like all good modern vulnerabilities, it has a name, EFAIL, and a dedicated website:

The EFAIL attacks exploit vulnerabilities in the OpenPGP and S/MIME standards to reveal the plaintext of encrypted emails. In a nutshell, EFAIL abuses active content of HTML emails, for example externally loaded images or styles, to exfiltrate plaintext through requested URLs. To create these exfiltration channels, the attacker first needs access to the encrypted emails, for example, by eavesdropping on network traffic, compromising email accounts, email servers, backup systems or client computers. The emails could even have been collected years ago.

The attacker changes an encrypted email in a particular way and sends this changed encrypted email to the victim. The victim’s email client decrypts the email and loads any external content, thus exfiltrating the plaintext to the attacker.

The weakness isn’t in the OpenPGP or S/MIME encryption algorithms themselves but in how mail clients interact with encrypted e-mails. If your e-mail client is configured to automatically decrypt encrypted e-mails and allows HTML content to be displayed, the encrypted potion of your e-mail could be exfiltrated by a malicious attacker.

I generally recommend against using e-mail for secure communications in any capacity. OpenPGP and S/MIME are bandages applied to an insecure protocol. Due to their nature as a bolted on feature added after the fact, they are unable to encrypt a lot of data in your e-mail (the only thing they can encrypt is the body). However, if you are going to use it, I generally recommend against allowing your client to automatically decrypt your encrypted e-mails. Instead at least require that your enter a password to decrypt your private key (this wouldn’t defend against this attack if your client is configured to display HTML e-mail content but it would prevent malicious e-mails from automatically exfiltrating encrypted content). Better yet, have your system setup in such a manner where you actually copy the encrypted contents of an e-mail into a separate decryption program, such as the OpenPGP command line tools, to view the secure contents. Finally, I would recommend disabling the ability to display HTML e-mails in your client if you are at all concerned about security.

If you perform the above practices, you can mitigate this attack… on your system. The real problem is, as always, other people’s systems. While you may perform the above practices, you can’t guarantee that everybody with whom you communicate will as well. If an attacker can exploit one party, they will generally get the e-mails sent by all parties. This is why I’d recommend using a communication tool that was designed to be secure from the beginning, such as Signal, over e-mail with OpenPGP or S/MIME. While tools like Signal aren’t bulletproof, they are designed to be secure by default, which makes them less susceptible to vulnerabilities created by an improper configuration.

Written by Christopher Burg

May 15th, 2018 at 11:00 am

Set a Strong Password on Your Phone

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My girlfriend and I had to take our cat to the emergency vet last night so I didn’t have an opportunity to prepare much material for today. However, I will leave you with a security tip. You should set a strong password on your phone:

How long is your iPhone PIN? If you still use one that’s only made by six numbers (or worse, four!), you may want to change that.

Cops all over the United States are racing to buy a new and relatively cheap technology called GrayKey to unlock iPhones. GrayShift, the company that develops it, promises to crack any iPhone, regardless of the passcode that’s on it. GrayKey is able to unlock some iPhones in two hours, or three days for phones with six digit passcodes, according to an anonymous source who provided security firm Malwarebytes with pictures of the cracking device and some information about how it works.

The article goes on to explain that you should use a password with lowercase and upper case letters, numbers, and symbols. Frankly, I think such advice is antiquated and prefer the advice given in this XKCD comic. You can create more bits of entropy if you have a longer password that is easier to remember. Instead of having something like “Sup3r53cretP@5sw0rd” you could have “garish-bethel-perry-best-finale.” The second is easier to remember and is actually longer. Moreover, you can increase your security by tacking on additional words. If you want a randomly generated password, you can use a Diceware program such as this one (which I used to generate the latter of the two passwords.

Written by Christopher Burg

April 19th, 2018 at 10:00 am

You Can’t Predict What Will Set an Individual Off

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I’m sure you’ve already heard about the shooting at YouTube’s headquarters. Before evidence of the shooter’s motives was revealed, most people predicted the common justifications given by or ascribed to shooters (an attack in the name of ISIS, a domestic issue, the shooter taking revenge for being bullied, etc.). However, this shooting took a slightly unusual twist when it was revealed that the shooter may have perpetrated the crime because she was upset about YouTube’s policy changes:

In several videos posted over the last year or so, she angrily spoke about the company’s policies, saying they were filtering her videos so they wouldn’t get any more views, and she was upset over demonetization. It appears the channels have now been completely removed by YouTube, citing policy violations.

Since the shooter committed suicide, we’ll never know for sure what her motivations were. But evidence indicates that her motivation may have been changes to YouTube’s monetization policies that caused at least some of her videos to be demonetized. If this was indeed her motivation, it goes to show that you can’t predict what will set an individual off.

Any action a company or individual takes is potentially dangerous. Although a vast majority of policy decisions don’t result in violence, once in a while the decision to either maintain or change a policy can result in a disgruntled individual responding with violence.

Part of the reason security is so difficult is because people are unpredictable. Who would have predicted that YouTube’s decision to demonetize some videos would result in an individual going to the company’s headquarters and opening fire on employees before turning the gun on herself?

Written by Christopher Burg

April 5th, 2018 at 10:00 am

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A Security Issue Is Still a Security Issue Even If It’s a Hit Job

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A series of flaws were revealed in AMD’s line of processors. The aftermath of these kinds of revelations usually involves a lot of people trying to assess the impact and threat. Can the flaws be exploited remotely? If they can be exploited remotely, is there a way to detect if a system has been exploited? What actions can be taken to mitigate these flaws? Instead of the usual assessment, the aftermath of this revelation has been dominated by people claiming that this revelation was actually a hit job secretly instigated by Intel and individuals wanting to manipulate AMD’s stock price:

Here’s a histrionic quote for you: “AMD must cease the sale of Ryzen and EPYC chips in the interest of public safety.”

That’s a real quote from Viceroy Research’s deranged, apoplectic report on CTS Labs’ security allegations against AMD’s Ryzen architecture. The big story today seemed to mirror Meltdown, except for AMD: CTS Labs, a research company supposedly started in 2017, has launched a report declaring glaring security flaws for AMD’s processors. By and large, the biggest flaw revolves around the user installing bad microcode.

There are roots in legitimacy here, but as we dug deep into the origins of the companies involved in this new hit piece on AMD, we found peculiar financial connections that make us question the motive behind the reportage.

The goal here is to research whether the hysterical whitepapers — hysterical as in “crazy,” not “funny” — have any weight to them, and where these previously unknown companies come from.

A lot of people seem to have lost sight of the fact that just because a revelation is a hit job (which I’m not saying this revelation is) doesn’t mean that the revealed exploit isn’t a legitimate exploit. Even if CTS Labs is a company secretly created by Intel for the specific purpose of wrecking AMD’s reputation, the revealed exploits need to be assessed and, if they’re found to be legitimate exploits, addressed.

Written by Christopher Burg

March 15th, 2018 at 10:00 am

Spook Squad

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I’ve often wondered how Geek Squad stays in business. The prices it charges for even the most trivial repairs are absurd. More and more I’m becoming convinced that Geek Squad stays in business because it is being propped up by the Federal Bureau of Investigations (FBI):

After the prosecution of a California doctor revealed the FBI’s ties to a Best Buy Geek Squad computer repair facility in Kentucky, new documents released to EFF show that the relationship goes back years. The records also confirm that the FBI has paid Geek Squad employees as informants.

EFF filed a Freedom of Information Act (FOIA) lawsuit last year to learn more about how the FBI uses Geek Squad employees to flag illegal material when people pay Best Buy to repair their computers. The relationship potentially circumvents computer owners’ Fourth Amendment rights.

While Geek Squad has been caught red handed working with the FBI, any employee at any computer repair company could be operating under the same deal. The FBI has a vested interest in access the information on as many computers as possible and people who repair computers often have unrestricted access to a lot of information on a lot of computers.

If you’re going to send your computer to somebody else for repairs, here are my recommendations to guard your privacy. If the device you’re sending in has a removable hard drive, remove the drive that is in it and replace it with a blank drive (one that has never been used to store personal information). On the blank drive install the operating system that came on the device and a user account with generic credentials (this is one of the few times where the password “password” is a good idea) so the repair person can log in. By doing this you ensure that the repair person doesn’t have access to any of your personal data. When the device comes back, format the drive that you provided the repair person, remove it, and install the hard drive with your data again.

If your device doesn’t have a removable drive, ensure that the first thing you do when you initially start the device after getting it out of the box is enable full disk encryption. When you need to send the device in for repairs, format the drive, reinstall the default operating system, setup a user account with generic credentials, and send the device in. When the drive comes back, wipe the drive again and restore your data from a backup. For those who are wondering why full disk encryption should be enabled it’s because formatting a drive doesn’t necessarily erase the data. By default formatting a drive wipes the file allocation table but leaves the data preserved. Enabling full disk encryption ensures that the data on the drive is unreadable without the proper decryption key. While formatting won’t erase the data, the data will be unreadable to the repair man if they attempt to restore the old file allocation table to pilfer your data for law enforcers.

Written by Christopher Burg

March 7th, 2018 at 11:00 am

The Beginning of the End for Unsecured Websites

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Chrome looks to be the first browser that is going to call a spade a spade. Starting in July 2018, Chrome will list all websites that aren’t utilizing HTTPS as unsecured:

For the past several years, we’ve moved toward a more secure web by strongly advocating that sites adopt HTTPS encryption. And within the last year, we’ve also helped users understand that HTTP sites are not secure by gradually marking a larger subset of HTTP pages as “not secure”. Beginning in July 2018 with the release of Chrome 68, Chrome will mark all HTTP sites as “not secure”.

I think Let’s Encrypt was the catalyst that made this decision possible. Before Let’s Encrypt was released, acquiring and managing TLS certificates could be a painful experience. What made matters worse is that the entire process had to be redone whenever the acquired TLS certificates expired. Let’s Encrypt turned that oftentimes annoying and expensive process into an easy command. This made it feasible for even amateur website administrators to implement HTTPS.

The Internet is slowly moving to a more secure model. HTTPS not only prevents third parties from seeing your web traffic but, maybe even more importantly, it also prevents third parties from altering your web traffic.

Written by Christopher Burg

February 16th, 2018 at 10:00 am

Let’s Put a Remotely Accessible Computer in a Door Lock

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Let’s put a remotely accessible computer in a door lock, what could possibly go wrong?

A HomeKit vulnerability in the current version of iOS 11.2 has been demonstrated to 9to5Mac that allows unauthorized control of accessories including smart locks and garage door openers. Our understanding is Apple has rolled out a server-side fix that now prevent unauthorized access from occurring while limiting some functionality, and an update to iOS 11.2 coming next week will restore that full functionality.

The Internet of Things (IoT) introduces all sorts of new and interesting exploits. These exploits range from minor, such as your lights turn colors, to severe, such as having your doors unlock for an unauthorized person. Unfortunately, since software is already incredibly complex and becoming more so every day it’s unlikely we’ll see secure IoT devices anytime in the near future. Fortunately, it appears that Apple caught this vulnerability and was able to patch it before it was actively exploited.

Written by Christopher Burg

December 8th, 2017 at 10:00 am

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