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Schneier on Security

Schneier on Security

The Effects of Iran's Telegram Ban

The Center for Human Rights in Iran has released a report outlining the effect's of that country's ban on Telegram, a secure messaging app used by about half of the country.

The ban will disrupt the most important, uncensored platform for information and communication in Iran, one that is used extensively by activists, independent and citizen journalists, dissidents and international media. It will also impact electoral politics in Iran, as centrist, reformist and other relatively moderate political groups that are allowed to participate in Iran's elections have been heavily and successfully using Telegram to promote their candidates and electoral lists during elections. State-controlled domestic apps and media will not provide these groups with such a platform, even as they continue to do so for conservative and hardline political forces in the country, significantly aiding the latter.

From a Wired article:

Researchers found that the ban has had broad effects, hindering and chilling individual speech, forcing political campaigns to turn to state-sponsored media tools, limiting journalists and activists, curtailing international interactions, and eroding businesses that grew their infrastructure and reach off of Telegram.

It's interesting that the analysis doesn't really center around the security properties of Telegram, but more around its ubiquity as a messaging platform in the country.

Tags: censorship, Iran, privacy, Telegram

Posted on June 22, 2018 at 12:58 PM11 Comments

Perverse Vulnerability from Interaction between 2-Factor Authentication and iOS AutoFill

Apple is rolling out an iOS security usability feature called Security code AutoFill. The basic idea is that the OS scans incoming SMS messages for security codes and suggests them in AutoFill, so that people can use them without having to memorize or type them.

Sounds like a really good idea, but Andreas Gutmann points out an application where this could become a vulnerability: when authenticating transactions:

Transaction authentication, as opposed to user authentication, is used to attest the correctness of the intention of an action rather than just the identity of a user. It is most widely known from online banking, where it is an essential tool to defend against sophisticated attacks. For example, an adversary can try to trick a victim into transferring money to a different account than the one intended. To achieve this the adversary might use social engineering techniques such as phishing and vishing and/or tools such as Man-in-the-Browser malware.

Transaction authentication is used to defend against these adversaries. Different methods exist but in the one of relevance here -- which is among the most common methods currently used -- the bank will summarise the salient information of any transaction request, augment this summary with a TAN tailored to that information, and send this data to the registered phone number via SMS. The user, or bank customer in this case, should verify the summary and, if this summary matches with his or her intentions, copy the TAN from the SMS message into the webpage.

This new iOS feature creates problems for the use of SMS in transaction authentication. Applied to 2FA, the user would no longer need to open and read the SMS from which the code has already been conveniently extracted and presented. Unless this feature can reliably distinguish between OTPs in 2FA and TANs in transaction authentication, we can expect that users will also have their TANs extracted and presented without context of the salient information, e.g. amount and destination of the transaction. Yet, precisely the verification of this salient information is essential for security. Examples of where this scenario could apply include a Man-in-the-Middle attack on the user accessing online banking from their mobile browser, or where a malicious website or app on the user's phone accesses the bank's legitimate online banking service.

This is an interesting interaction between two security systems. Security code AutoFill eliminates the need for the user to view the SMS or memorize the one-time code. Transaction authentication assumes the user read and approved the additional information in the SMS message before using the one-time code.

Tags: Apple, authentication, banking, iOS, SMS, two-factor authentication, usability

Posted on June 20, 2018 at 6:51 AM30 Comments

Are Free Societies at a Disadvantage in National Cybersecurity

Jack Goldsmith and Stuart Russell just published an interesting paper, making the case that free and democratic nations are at a structural disadvantage in nation-on-nation cyberattack and defense. From a blog post:

It seeks to explain why the United States is struggling to deal with the "soft" cyber operations that have been so prevalent in recent years: cyberespionage and cybertheft, often followed by strategic publication; information operations and propaganda; and relatively low-level cyber disruptions such as denial-of-service and ransomware attacks. The main explanation is that constituent elements of U.S. society -- a commitment to free speech, privacy and the rule of law; innovative technology firms; relatively unregulated markets; and deep digital sophistication -- create asymmetric vulnerabilities that foreign adversaries, especially authoritarian ones, can exploit. These asymmetrical vulnerabilities might explain why the United States so often appears to be on the losing end of recent cyber operations and why U.S. attempts to develop and implement policies to enhance defense, resiliency, response or deterrence in the cyber realm have been ineffective.

I have long thought this to be true. There are defensive cybersecurity measures that a totalitarian country can take that a free, open, democratic country cannot. And there are attacks against a free, open, democratic country that just don't matter to a totalitarian country. That makes us more vulnerable. (I don't mean to imply -- and neither do Russell and Goldsmith -- that this disadvantage implies that free societies are overall worse, but it is an asymmetry that we should be aware of.)

I do worry that these disadvantages will someday become intolerable. Dan Geer often said that "the price of freedom is the probability of crime." We are willing to pay this price because it isn't that high. As technology makes individual and small-group actors more powerful, this price will get higher. Will there be a point in the future where free and open societies will no longer be able to survive? I honestly don't know.

EDITED TO ADD (6/21): Jack Goldsmith also wrote this.

Tags: cyberattack, cybercrime, cyberespionage, cybersecurity, national security policy, privacy

Posted on June 19, 2018 at 6:54 AM48 Comments

Ridiculously Insecure Smart Lock

Tapplock sells an "unbreakable" Internet-connected lock that you can open with your fingerprint. It turns out that:

  1. The lock broadcasts its Bluetooth MAC address in the clear, and you can calculate the unlock key from it.

  2. Any Tapplock account an unlock every lock.

  3. You can open the lock with a screwdriver.

Regarding the third flaw, the manufacturer has responded that "...the lock is invincible to the people who do not have a screwdriver."

You can't make this stuff up.

EDITED TO ADD: The quote at the end is from a different smart lock manufacturer. Apologies for that.

Tags: Bluetooth, locks, physical security

Posted on June 18, 2018 at 6:19 AM44 Comments

Russian Censorship of Telegram

Internet censors have a new strategy in their bid to block applications and websites: pressuring the large cloud providers that host them. These providers have concerns that are much broader than the targets of censorship efforts, so they have the choice of either standing up to the censors or capitulating in order to maximize their business. Today's Internet largely reflects the dominance of a handful of companies behind the cloud services, search engines and mobile platforms that underpin the technology landscape. This new centralization radically tips the balance between those who want to censor parts of the Internet and those trying to evade censorship. When the profitable answer is for a software giant to acquiesce to censors' demands, how long can Internet freedom last?

The recent battle between the Russian government and the Telegram messaging app illustrates one way this might play out. Russia has been trying to block Telegram since April, when a Moscow court banned it after the company refused to give Russian authorities access to user messages. Telegram, which is widely used in Russia, works on both iPhone and Android, and there are Windows and Mac desktop versions available. The app offers optional end-to-end encryption, meaning that all messages are encrypted on the sender's phone and decrypted on the receiver's phone; no part of the network can eavesdrop on the messages.

Since then, Telegram has been playing cat-and-mouse with the Russian telecom regulator Roskomnadzor by varying the IP address the app uses to communicate. Because Telegram isn't a fixed website, it doesn't need a fixed IP address. Telegram bought tens of thousands of IP addresses and has been quickly rotating through them, staying a step ahead of censors. Cleverly, this tactic is invisible to users. The app never sees the change, or the entire list of IP addresses, and the censor has no clear way to block them all.

A week after the court ban, Roskomnadzor countered with an unprecedented move of its own: blocking 19 million IP addresses, many on Amazon Web Services and Google Cloud. The collateral damage was widespread: The action inadvertently broke many other web services that use those platforms, and Roskomnadzor scaled back after it became clear that its action had affected services critical for Russian business. Even so, the censor is still blocking millions of IP addresses.

More recently, Russia has been pressuring Apple not to offer the Telegram app in its iPhone App Store. As of this writing, Apple has not complied, and the company has allowed Telegram to download a critical software update to iPhone users (after what the app's founder called a delay last month). Roskomnadzor could further pressure Apple, though, including by threatening to turn off its entire iPhone app business in Russia.

Telegram might seem a weird app for Russia to focus on. Those of us who work in security don't recommend the program, primarily because of the nature of its cryptographic protocols. In general, proprietary cryptography has numerous fatal security flaws. We generally recommend Signal for secure SMS messaging, or, if having that program on your computer is somehow incriminating, WhatsApp. (More than 1.5 billion people worldwide use WhatsApp.) What Telegram has going for it is that it works really well on lousy networks. That's why it is so popular in places like Iran and Afghanistan. (Iran is also trying to ban the app.)

What the Russian government doesn't like about Telegram is its anonymous broadcast feature­ -- channel capability and chats -- ­which makes it an effective platform for political debate and citizen journalism. The Russians might not like that Telegram is encrypted, but odds are good that they can simply break the encryption. Telegram's role in facilitating uncontrolled journalism is the real issue.

Iran attempts to block Telegram have been more successful than Russia's, less because Iran's censorship technology is more sophisticated but because Telegram is not willing to go as far to defend Iranian users. The reasons are not rooted in business decisions. Simply put, Telegram is a Russian product and the designers are more motivated to poke Russia in the eye. Pavel Durov, Telegram's founder, has pledged millions of dollars to help fight Russian censorship.

For the moment, Russia has lost. But this battle is far from over. Russia could easily come back with more targeted pressure on Google, Amazon and Apple. A year earlier, Zello used the same trick Telegram is using to evade Russian censors. Then, Roskomnadzor threatened to block all of Amazon Web Services and Google Cloud; and in that instance, both companies forced Zello to stop its IP-hopping censorship-evasion tactic.

Russia could also further develop its censorship infrastructure. If its capabilities were as finely honed as China's, it would be able to more effectively block Telegram from operating. Right now, Russia can block only specific IP addresses, which is too coarse a tool for this issue. Telegram's voice capabilities in Russia are significantly degraded, however, probably because high-capacity IP addresses are easier to block.

Whatever its current frustrations, Russia might well win in the long term. By demonstrating its willingness to suffer the temporary collateral damage of blocking major cloud providers, it prompted cloud providers to block another and more effective anti-censorship tactic, or at least accelerated the process. In April, Google and Amazon banned­ -- and technically blocked­ -- the practice of "domain fronting," a trick anti-censorship tools use to get around Internet censors by pretending to be other kinds of traffic. Developers would use popular websites as a proxy, routing traffic to their own servers through another website­ -- in this case Google.com­ -- to fool censors into believing the traffic was intended for Google.com. The anonymous web-browsing tool Tor has used domain fronting since 2014. Signal, since 2016. Eliminating the capability is a boon to censors worldwide.

Tech giants have gotten embroiled in censorship battles for years. Sometimes they fight and sometimes they fold, but until now there have always been options. What this particular fight highlights is that Internet freedom is increasingly in the hands of the world's largest Internet companies. And while freedom may have its advocates -- ­the American Civil Liberties Union has tweeted its support for those companies, and some 12,000 people in Moscow protested against the Telegram ban­ -- actions such as disallowing domain fronting illustrate that getting the big tech companies to sacrifice their near-term commercial interests will be an uphill battle. Apple has already removed anti-censorship apps from its Chinese app store.

In 1993, John Gilmore famously said that "The Internet interprets censorship as damage and routes around it." That was technically true when he said it but only because the routing structure of the Internet was so distributed. As centralization increases, the Internet loses that robustness, and censorship by governments and companies becomes easier.

This essay previously appeared on Lawfare.com.

Tags: Android, Apple, censorship, cloud computing, iPhone, Russia, Signal, Telegram, WhatsApp

Posted on June 13, 2018 at 6:55 AM36 Comments

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Schneier on Security is a personal website. Opinions expressed are not necessarily those of IBM Resilient.