Entries Tagged "Wi-Fi"

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Microsoft Buys Corp.com

A few months ago, Brian Krebs told the story of the domain corp.com, and how it is basically a security nightmare:

At issue is a problem known as “namespace collision,” a situation where domain names intended to be used exclusively on an internal company network end up overlapping with domains that can resolve normally on the open Internet.

Windows computers on an internal corporate network validate other things on that network using a Microsoft innovation called Active Directory, which is the umbrella term for a broad range of identity-related services in Windows environments. A core part of the way these things find each other involves a Windows feature called “DNS name devolution,” which is a kind of network shorthand that makes it easier to find other computers or servers without having to specify a full, legitimate domain name for those resources.

For instance, if a company runs an internal network with the name internalnetwork.example.com, and an employee on that network wishes to access a shared drive called “drive1,” there’s no need to type “drive1.internalnetwork.example.com” into Windows Explorer; typing “\\drive1\” alone will suffice, and Windows takes care of the rest.

But things can get far trickier with an internal Windows domain that does not map back to a second-level domain the organization actually owns and controls. And unfortunately, in early versions of Windows that supported Active Directory — Windows 2000 Server, for example — the default or example Active Directory path was given as “corp,” and many companies apparently adopted this setting without modifying it to include a domain they controlled.

Compounding things further, some companies then went on to build (and/or assimilate) vast networks of networks on top of this erroneous setting.

Now, none of this was much of a security concern back in the day when it was impractical for employees to lug their bulky desktop computers and monitors outside of the corporate network. But what happens when an employee working at a company with an Active Directory network path called “corp” takes a company laptop to the local Starbucks?

Chances are good that at least some resources on the employee’s laptop will still try to access that internal “corp” domain. And because of the way DNS name devolution works on Windows, that company laptop online via the Starbucks wireless connection is likely to then seek those same resources at “corp.com.”

In practical terms, this means that whoever controls corp.com can passively intercept private communications from hundreds of thousands of computers that end up being taken outside of a corporate environment which uses this “corp” designation for its Active Directory domain.

Microsoft just bought it, so it wouldn’t fall into the hands of any bad actors:

In a written statement, Microsoft said it acquired the domain to protect its customers.

“To help in keeping systems protected we encourage customers to practice safe security habits when planning for internal domain and network names,” the statement reads. “We released a security advisory in June of 2009 and a security update that helps keep customers safe. In our ongoing commitment to customer security, we also acquired the Corp.com domain.”

Posted on April 9, 2020 at 6:45 AMView Comments

Wi-Fi Chip Vulnerability

There’s a vulnerability in Wi-Fi hardware that breaks the encryption:

The vulnerability exists in Wi-Fi chips made by Cypress Semiconductor and Broadcom, the latter a chipmaker Cypress acquired in 2016. The affected devices include iPhones, iPads, Macs, Amazon Echos and Kindles, Android devices, and Wi-Fi routers from Asus and Huawei, as well as the Raspberry Pi 3. Eset, the security company that discovered the vulnerability, said the flaw primarily affects Cypress’ and Broadcom’s FullMAC WLAN chips, which are used in billions of devices. Eset has named the vulnerability Kr00k, and it is tracked as CVE-2019-15126.

Manufacturers have made patches available for most or all of the affected devices, but it’s not clear how many devices have installed the patches. Of greatest concern are vulnerable wireless routers, which often go unpatched indefinitely.

That’s the real problem. Many of these devices won’t get patched — ever.

Posted on March 3, 2020 at 6:43 AMView Comments

Wi-Fi Hotspot Tracking

Free Wi-Fi hotspots can track your location, even if you don’t connect to them. This is because your phone or computer broadcasts a unique MAC address.

What distinguishes location-based marketing hotspot providers like Zenreach and Euclid is that the personal information you enter in the captive portal­ — like your email address, phone number, or social media profile­ — can be linked to your laptop or smartphone’s Media Access Control (MAC) address. That’s the unique alphanumeric ID that devices broadcast when Wi-Fi is switched on.

As Euclid explains in its privacy policy, “…if you bring your mobile device to your favorite clothing store today that is a Location — ­and then a popular local restaurant a few days later that is also a Location­ — we may know that a mobile device was in both locations based on seeing the same MAC Address.”

MAC addresses alone don’t contain identifying information besides the make of a device, such as whether a smartphone is an iPhone or a Samsung Galaxy. But as long as a device’s MAC address is linked to someone’s profile, and the device’s Wi-Fi is turned on, the movements of its owner can be followed by any hotspot from the same provider.

“After a user signs up, we associate their email address and other personal information with their device’s MAC address and with any location history we may previously have gathered (or later gather) for that device’s MAC address,” according to Zenreach’s privacy policy.

The defense is to turn Wi-Fi off on your phone when you’re not using it.

EDITED TO ADD: Note that the article is from 2018. Not that I think anything is different today….

Posted on October 10, 2019 at 5:49 AMView Comments

How Apple's "Find My" Feature Works

Matthew Green intelligently speculates about how Apple’s new “Find My” feature works.

If you haven’t already been inspired by the description above, let me phrase the question you ought to be asking: how is this system going to avoid being a massive privacy nightmare?

Let me count the concerns:

  • If your device is constantly emitting a BLE signal that uniquely identifies it, the whole world is going to have (yet another) way to track you. Marketers already use WiFi and Bluetooth MAC addresses to do this: Find My could create yet another tracking channel.
  • It also exposes the phones who are doing the tracking. These people are now going to be sending their current location to Apple (which they may or may not already be doing). Now they’ll also be potentially sharing this information with strangers who “lose” their devices. That could go badly.
  • Scammers might also run active attacks in which they fake the location of your device. While this seems unlikely, people will always surprise you.

The good news is that Apple claims that their system actually does provide strong privacy, and that it accomplishes this using clever cryptography. But as is typical, they’ve declined to give out the details how they’re going to do it. Andy Greenberg talked me through an incomplete technical description that Apple provided to Wired, so that provides many hints. Unfortunately, what Apple provided still leaves huge gaps. It’s into those gaps that I’m going to fill in my best guess for what Apple is actually doing.

Posted on June 20, 2019 at 12:27 PMView Comments

Vulnerabilities in the WPA3 Wi-Fi Security Protocol

Researchers have found several vulnerabilities in the WPA3 Wi-Fi security protocol:

The design flaws we discovered can be divided in two categories. The first category consists of downgrade attacks against WPA3-capable devices, and the second category consists of weaknesses in the Dragonfly handshake of WPA3, which in the Wi-Fi standard is better known as the Simultaneous Authentication of Equals (SAE) handshake. The discovered flaws can be abused to recover the password of the Wi-Fi network, launch resource consumption attacks, and force devices into using weaker security groups. All attacks are against home networks (i.e. WPA3-Personal), where one password is shared among all users.

News article. Research paper: “Dragonblood: A Security Analysis of WPA3’s SAE Handshake“:

Abstract: The WPA3 certification aims to secure Wi-Fi networks, and provides several advantages over its predecessor WPA2, such as protection against offline dictionary attacks and forward secrecy. Unfortunately, we show that WPA3 is affected by several design flaws,and analyze these flaws both theoretically and practically. Most prominently, we show that WPA3’s Simultaneous Authentication of Equals (SAE) handshake, commonly known as Dragonfly, is affected by password partitioning attacks. These attacks resemble dictionary attacks and allow an adversary to recover the password by abusing timing or cache-based side-channel leaks. Our side-channel attacks target the protocol’s password encoding method. For instance, our cache-based attack exploits SAE’s hash-to-curve algorithm. The resulting attacks are efficient and low cost: brute-forcing all 8-character lowercase password requires less than 125$in Amazon EC2 instances. In light of ongoing standardization efforts on hash-to-curve, Password-Authenticated Key Exchanges (PAKEs), and Dragonfly as a TLS handshake, our findings are also of more general interest. Finally, we discuss how to mitigate our attacks in a backwards-compatible manner, and explain how minor changes to the protocol could have prevented most of our attack

Posted on April 15, 2019 at 2:00 PMView Comments

Security Analysis of the LIFX Smart Light Bulb

The security is terrible:

In a very short limited amount of time, three vulnerabilities have been discovered:

  • Wifi credentials of the user have been recovered (stored in plaintext into the flash memory).
  • No security settings. The device is completely open (no secure boot, no debug interface disabled, no flash encryption).
  • Root certificate and RSA private key have been extracted.

Boing Boing post.

Posted on January 30, 2019 at 10:00 AMView Comments

Counting People through a Wall with Wi-Fi

Interesting research:

In the team’s experiments, one WiFi transmitter and one WiFi receiver are behind walls, outside a room in which a number of people are present. The room can get very crowded with as many as 20 people zigzagging each other. The transmitter sends a wireless signal whose received signal strength (RSSI) is measured by the receiver. Using only such received signal power measurements, the receiver estimates how many people are inside the room ­ an estimate that closely matches the actual number. It is noteworthy that the researchers do not do any prior measurements or calibration in the area of interest; their approach has only a very short calibration phase that need not be done in the same area.

Academic paper.

Posted on September 27, 2018 at 7:43 AMView Comments

Major Bluetooth Vulnerability

Bluetooth has a serious security vulnerability:

In some implementations, the elliptic curve parameters are not all validated by the cryptographic algorithm implementation, which may allow a remote attacker within wireless range to inject an invalid public key to determine the session key with high probability. Such an attacker can then passively intercept and decrypt all device messages, and/or forge and inject malicious messages.

Paper. Website. Three news articles.

This is serious. Update your software now, and try not to think about all of the Bluetooth applications that can’t be updated.

Posted on July 25, 2018 at 2:08 PMView Comments


Everyone is writing about the new WPA3 Wi-Fi security standard, and how it improves security over the current WPA2 standard.

This summary is as good as any other:

The first big new feature in WPA3 is protection against offline, password-guessing attacks. This is where an attacker captures data from your Wi-Fi stream, brings it back to a private computer, and guesses passwords over and over again until they find a match. With WPA3, attackers are only supposed to be able to make a single guess against that offline data before it becomes useless; they’ll instead have to interact with the live Wi-Fi device every time they want to make a guess. (And that’s harder since they need to be physically present, and devices can be set up to protect against repeat guesses.)

WPA3’s other major addition, as highlighted by the Alliance, is forward secrecy. This is a privacy feature that prevents older data from being compromised by a later attack. So if an attacker captures an encrypted Wi-Fi transmission, then cracks the password, they still won’t be able to read the older data — they’d only be able to see new information currently flowing over the network.

Note that we’re just getting the new standard this week. Actual devices that implement the standard are still months away.

Posted on July 12, 2018 at 6:11 AMView Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.