Home Security Flaw in WPA2 protocol puts most Wi-Fi devices at risk
Flaw in WPA2 protocol puts most Wi-Fi devices at risk Featured

Belgian researcher Mathy Vanhoef of imec-DistriNet, KU Leuven has revealed details of a major flaw in the WPA2 protocol that is used for wireless security.

Vanhoef said tonight (Australian time) that attackers within range of a victim could exploit these weaknesses using key reinstallation attacks (KRACKs). (A detailed paper on the flaws is here.)

"Concretely, attackers can use this novel attack technique to read information that was previously assumed to be safely encrypted. This can be abused to steal sensitive information such as credit card numbers, passwords, chat messages, emails, photos, and so on," he wrote.

"The attack works against all modern protected Wi-Fi networks. Depending on the network configuration, it is also possible to inject and manipulate data. For example, an attacker might be able to inject ransomware or other malware into websites."

Vanhoef said the flaws were in the Wi-Fi standard itself, and not in individual products or implementations.

"Therefore, any correct implementation of WPA2 is likely affected. To prevent the attack, users must update affected products as soon as security updates become available," he wrote.

"Note that if your device supports Wi-Fi, it is most likely affected. During our initial research, we discovered ourselves that Android, Linux, Apple, Windows, OpenBSD, MediaTek, Linksys, and others, are all affected by some variant of the attacks."

Vanhoef said there was no need for a WPA3 implementation.

"No, luckily implementations can be patched in a backwards-compatible manner. This means a patched client can still communicate with an unpatched access point, and vice versa," he wrote

"In other words, a patched client or access points send exactly the same handshake messages as before, and at exactly the same moments in time. However, the security updates will assure a key is only installed once, preventing our attacks. So again, update all your devices once security updates are available."

The research behind the attack will be presented at the Computer and Communications Security conference, and at the Black Hat Europe conference, to be held from 30 October and 2 December respectively.

As a proof of concept, Vanhoef said he had carried out a key reinstallation attack against an Android smartphone.

"In this demonstration, the attacker is able to decrypt all data that the victim transmits. For an attacker this is easy to accomplish, because our key reinstallation attack is exceptionally devastating against Linux and Android 6.0 or higher," he wrote.

"This is because Android and Linux can be tricked into (re)installing an all-zero encryption key. When attacking other devices, it is harder to decrypt all packets, although a large number of packets can nevertheless be decrypted.

"In any case, the following demonstration highlights the type of information that an attacker can obtain when performing key reinstallation attacks against protected Wi-Fi networks."

The main attack that Vanhoef demonstrated was against the 4-way handshake of the WPA2 protocol that is executed when a client wants to join a protected Wi-Fi network.

It is used to confirm that both the client and access point possess the correct credentials (e.g. the pre-shared password of the network). Simultaneously, the 4-way handshake also negotiates a fresh encryption key that will be used to encrypt all subsequent traffic. All modern protected Wi-Fi networks use the 4-way handshake.

Explaining the attack, Vanhoef said in a key reinstallation attack, the adversary tricked a victim into reinstalling an already-in-use key.

"This is achieved by manipulating and replaying cryptographic handshake messages. When the victim reinstalls the key, associated parameters such as the incremental transmit packet number (i.e. nonce) and receive packet number (i.e. replay counter) are reset to their initial value.

"Essentially, to guarantee security, a key should only be installed and used once. Unfortunately, we found this is not guaranteed by the WPA2 protocol. By manipulating cryptographic handshakes, we can abuse this weakness in practice."

Well-known British security researcher Kevin Beaumont made a list of the takeaways from the detailed research paper. They were:

  • It is patchable, both client and server (Wi-Fi) side.
  • Linux patches are available now. Linux distributions should have it very shortly.
  • The attack doesn’t realistically doesn’t work against Windows or iOS devices. The Group vuln is there, but it’s not near enough to actually do anything of interest.
  • There is currently no publicly available code out there to attack this in the real world — you would need an incredibly high skill set and to be at the Wi-Fi base station to attack this.
  • Android is the issue, which is why the research paper concentrates on it. The issue with Android is people largely don’t patch.

The CVE identifiers assigned to track the products affected specific instantiations of the key reinstallation attack are given below:

CVE-2017-13077: Reinstallation of the pairwise encryption key (PTK-TK) in the 4-way handshake.

CVE-2017-13078: Reinstallation of the group key (GTK) in the 4-way handshake.

CVE-2017-13079: Reinstallation of the integrity group key (IGTK) in the 4-way handshake.

CVE-2017-13080: Reinstallation of the group key (GTK) in the group key handshake.

CVE-2017-13081: Reinstallation of the integrity group key (IGTK) in the group key handshake.

CVE-2017-13082: Accepting a retransmitted Fast BSS Transition (FT) Reassociation Request and reinstalling the pairwise encryption key (PTK-TK) while processing it.

CVE-2017-13084: Reinstallation of the STK key in the PeerKey handshake.

CVE-2017-13086: reinstallation of the Tunneled Direct-Link Setup (TDLS) PeerKey (TPK) key in the TDLS handshake.

CVE-2017-13087: reinstallation of the group key (GTK) when processing a Wireless Network Management (WNM) Sleep Mode Response frame.

CVE-2017-13088: reinstallation of the integrity group key (IGTK) when processing a Wireless Network Management (WNM) Sleep Mode Response frame.

LEARN HOW TO REDUCE YOUR RISK OF A CYBER ATTACK

Australia is a cyber espionage hot spot.

As we automate, script and move to the cloud, more and more businesses are reliant on infrastructure that has the high potential to be exposed to risk.

It only takes one awry email to expose an accounts’ payable process, and for cyber attackers to cost a business thousands of dollars.

In the free white paper ‘6 Steps to Improve your Business Cyber Security’ you’ll learn some simple steps you should be taking to prevent devastating and malicious cyber attacks from destroying your business.

Cyber security can no longer be ignored, in this white paper you’ll learn:

· How does business security get breached?
· What can it cost to get it wrong?
· 6 actionable tips

DOWNLOAD NOW!

10 SIMPLE TIPS TO PROTECT YOUR ORGANISATION FROM RANSOMWARE

Ransomware attacks on businesses and institutions are now the most common type of malware breach, accounting for 39% of all IT security incidents, and they are still growing.

Criminal ransomware revenues are projected to reach $11.5B by 2019.

With a few simple policies and procedures, plus some cutting-edge endpoint countermeasures, you can effectively protect your business from the ransomware menace.

DOWNLOAD NOW!

Sam Varghese

website statistics

A professional journalist with decades of experience, Sam for nine years used DOS and then Windows, which led him to start experimenting with GNU/Linux in 1998. Since then he has written widely about the use of both free and open source software, and the people behind the code. His personal blog is titled Irregular Expression.

 

Popular News

 

Telecommunications

 

Sponsored News

 

 

 

 

Connect