Key reinstallation attacks: my suggested readings

Release the KRACKen!

Security researcher Mathy Vanhoef has discovered several vulnerabilities in the core of WPA2 protocol that could allow an attacker to hack into a Wi-Fi network and eavesdrop on the Internet communications.

WPA2 is a authentication scheme widely used to secure WiFi connections: now the standard has been compromised and this flaws impacting almost all Wi-Fi devices.

The flaw was dubbed KRACK (Key Reinstallation Attack): the proof-of-concept attack works against all modern protected Wi-Fi networks and can be used to steal sensitive information like credit card numbers, passwords, chat messages, emails, and photos.

Since the weaknesses reside in the Wi-Fi standard itself, and not in the implementations or any individual product, the attack works against:

– Both WPA1 and WPA2,
– Personal and enterprise networks,
– Ciphers WPA-TKIP, AES-CCMP, and GCMP

The paper is here. It’s pretty easy to read, and you should.

Below some interesting article about the new vulnerability:

We discovered serious weaknesses in WPA2, a protocol that secures all modern protected Wi-Fi networks. An attacker within range of a victim can exploit these weaknesses using key reinstallation attacks (KRACKs). Concretely, attackers can use this novel attack technique to read information that was previously assumed to be safely encrypted.

I don’t want to spend much time talking about KRACK itself, because the vulnerability is pretty straightforward. Instead, I want to talk about why this vulnerability continues to exist so many years after WPA was standardized. And separately, to answer a question: how did this attack slip through, despite the fact that the 802.11i handshake was formally proven secure?

However the flaws are not easy to exploit and require attackers to be in close proximity to a victim, thereby making the flaws somewhat less severe of a threat despite their ubiquity.

This is not a crypto bug but a protocol bug (a pretty obvious and trivial protocol bug).

I have created a list of known information regarding various WiFi vendors and whether new drivers are available. As this vulnerability is fairly new, there is little information available, I advise you to check this page throughout the coming days to see if new information is available.

Vanhoef describes the attack as being “exceptionally devastating against Linux and Android 6.0 or higher.”

However, don’t panic too much.

Currently, over two-fifths (41%) of Android devices are vulnerable to this kind of attack.

Always check to make sure there’s a green lock icon in the address bar of your browser. That lock indicates that an HTTPS (encrypted and therefore secure) connection to this particular website is being used. If someone attempts to use SSLstrip against you, the browser will be forced to use HTTP versions of websites, and the lock will disappear. If the lock is in place, your connection is still secure.

[…] consider browsing the Web with an extension or browser add-on like HTTPS Everywhere, which forces any site that supports https:// connections to encrypt your communications with the Web site — regardless of whether this is the default for that site.

It is important to keep in mind that it’s not only individuals who are impacted by this vulnerability, but also businesses. Any Wi-Fi deployment that uses WPA2 can be exploited. This means organizations should also push updates and be sure remote workers are securing their devices and systems as well.

Changing your Wi-Fi password won’t help: this attack doesn’t recover the password (PSK) itself, but instead allows an attacker to decrypt some of the content of some sessions.

Changing routers probably won’t help either, because there are numerous variants of the KRACK Attacks that affect most Wi-Fi software implementations in most operating systems.

So what can you do?

– Patch. Once patches become available, apply them expediciously.

– If possible, do not just rely on WPA2 for security. SSL / IPSec can provide an additional layer of defense

– Use wired networks if possible (always a good idea)

This is yet another of a series of marketed attacks; with a cool name, a website, and a logo. The Q&A on the website answers a lot of questions about the attack and its implications.

There are no reports yet of attackers attempting to exploit these vulnerabilities in the wild. However, as with all newly discovered vulnerabilities, it is only a matter of time before attacks are attempted.

Do you think your wireless network is secure because you’re using WPA2 encryption?

If yes, think again!

A devastating weakness plagues the WPA2 protocol used to secure all modern Wi-Fi networks, and it can be abused to decrypt traffic from enterprise and consumer networks with varying degrees of difficulty.

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