--- title: KRACK, WPA2 & Unforeseen Behaviour description: One of the biggest reasons for this panic about KRACK is that many people are unaware that WPA and WPA2 have long been considered broken. image: https://reflare.com/hubfs/Blog%20image%20in%20post/KRACK%2c%20WPA2%20%26%20Unforeseen%20Behaviour.png --- [![Reflare home](https://reflare.com/hs-fs/hubfs/Reflare%20website%20images/Reflare%20Logos/reflare%20logo.png?width=421&height=150&name=reflare%20logo.png "Reflare home")](https://reflare.com) [![logo](https://reflare.com/hs-fs/hubfs/Reflare%20website%20images/Reflare%20Logos/logo.png?width=262&height=82&name=logo.png "logo")](https://reflare.com/act3) [![reflare logo](https://reflare.com/hs-fs/hubfs/Reflare%20website%20images/Reflare%20Logos/reflare%20logo.png?width=168&height=60&name=reflare%20logo.png "reflare logo")](https://reflare.com/act3) - [Galena](https://reflare.com/galena) - [Galena Overview](https://reflare.com/galena) - [Galena for Tech Teams](https://reflare.com/technical-teams) - [Galena for L&D Teams](https://reflare.com/learning-development) - [Galena Security and Deployment](https://reflare.com/security-deployment) - Training - [Capture the Flag](https://reflare.com/rctf-reflare-capture-the-flag) - [Developers](https://reflare.com/rcsd) - [Administrators](https://reflare.com/rcsa) - [PCI DSS](https://reflare.com/rcsd) - Audit - [PCI DSS](https://reflare.com/pcidss) - [PCI 3DS](https://reflare.com/pci3ds) - [PCI PIN](https://reflare.com/pcipin) - [PCI DSS ASV](https://reflare.com/pcidssasv) - [Penetration Testing](https://reflare.com/penetration) - [Vulnerability Scanning](https://reflare.com/vulnerability) - [Advisory and Management](https://reflare.com/advisory) - [Research](https://reflare.com/research) - [Anatomy of a Breach](https://reflare.com/research/tag/anatomy-of-a-breach) - [High Tech](https://reflare.com/research/tag/high-tech) - [Infosec Culture](https://reflare.com/research/tag/infosec-culture) - [Infrastructure](https://reflare.com/research/tag/infrastructure) - [Normal People and Infosec](https://reflare.com/research/tag/normal-people-and-infosec) - [WTFWIB](https://whythefuckwasibreached.com/) - [About](https://reflare.com/about) - [Contact](https://reflare.com/contact) - [Company](https://reflare.com/about) - [Careers](https://reflare.com/careers) - [Service Status](https://statuspage.reflare.com/) - [日本語](https://jp.reflare.com/) [Login](https://reflare.com/login) [Buy Now](https://www.hubspot.com/) [Login](https://www.hubspot.com/)Login to your Reflare account - [Galena](https://reflare.com/galena) - [Galena Overview](https://reflare.com/galena) - [Galena for Tech Teams](https://reflare.com/technical-teams) - [Galena for L&D Teams](https://reflare.com/learning-development) - [Galena Security and Deployment](https://reflare.com/security-deployment) - Training - [Capture the Flag](https://reflare.com/rctf-reflare-capture-the-flag) - [Developers](https://reflare.com/rcsd) - [Administrators](https://reflare.com/rcsa) - [PCI DSS](https://reflare.com/rcsd) - Audit - [PCI DSS](https://reflare.com/pcidss) - [PCI 3DS](https://reflare.com/pci3ds) - [PCI PIN](https://reflare.com/pcipin) - [PCI DSS ASV](https://reflare.com/pcidssasv) - [Penetration Testing](https://reflare.com/penetration) - [Vulnerability Scanning](https://reflare.com/vulnerability) - [Advisory and Management](https://reflare.com/advisory) - [Research](https://reflare.com/research) - [Anatomy of a Breach](https://reflare.com/research/tag/anatomy-of-a-breach) - [High Tech](https://reflare.com/research/tag/high-tech) - [Infosec Culture](https://reflare.com/research/tag/infosec-culture) - [Infrastructure](https://reflare.com/research/tag/infrastructure) - [Normal People and Infosec](https://reflare.com/research/tag/normal-people-and-infosec) - [WTFWIB](https://whythefuckwasibreached.com/) - [About](https://reflare.com/about) - [Contact](https://reflare.com/contact) - [Company](https://reflare.com/about) - [Careers](https://reflare.com/careers) - [Service Status](https://statuspage.reflare.com/) - [日本語](https://jp.reflare.com/) [Buy Now](https://www.hubspot.com/) Research #### Share this [Share on Twitter](https://twitter.com/share?url=https://reflare.com/research/krack-wpa2-unforeseen-behaviour&text=KRACK,%20WPA2%20&%20Unforeseen%20Behaviour) [Share on Facebook](https://www.facebook.com/sharer/sharer.php?u=https://reflare.com/research/krack-wpa2-unforeseen-behaviour&t=KRACK,%20WPA2%20&%20Unforeseen%20Behaviour) [Share on LinkedIn](https://www.linkedin.com/shareArticle?mini=true&url=https://reflare.com/research/krack-wpa2-unforeseen-behaviour&t=KRACK,%20WPA2%20&%20Unforeseen%20Behaviour) # KRACK, WPA2 & Unforeseen Behaviour by [**Reflare Research Team**](https://reflare.com/research/author/reflare-research-team) on Oct 20, 2017 6:50:00 PM There are some shocking headlines going around about a newly discovered security flaw called KRACK. But one of the biggest reasons for this panic is because many people are unaware that WPA and WPA2 have long been considered broken. First Published 20th October 2017 ![KRACK, WPA2 & Unforeseen Behaviour](https://reflare.com/hs-fs/hubfs/Blog%20image%20in%20post/KRACK%2c%20WPA2%20%26%20Unforeseen%20Behaviour.png?width=672&height=448&name=KRACK%2c%20WPA2%20%26%20Unforeseen%20Behaviour.png) *Removal of the power supply has proven to be one successful risk mitigation strategy.* 4 min read  |  Reflare Research Team Earlier this week Mathy Vanhoef, a security researcher at the Belgian KU Leuven University, [released details](https://www.krackattacks.com/#details) on an attack which can compromise the security of Wifi networks secured with WPA and WPA2. These attacks - which were named KRACK - caused a significant stir in both the information security community and the general news media. Unfortunately, much of the reporting on this issue has been sensationalized and oversimplified to a point where even basics are misstated. In this briefing, we will have a look at KRACK and attempt to clarify the impact it is likely to have. ## The Basics WPA2 is an authentication and encryption algorithm used to secure 802.11 compliant wireless transmissions (“Wifi”). It replaced WPA (which has several theoretical vulnerabilities) and WEP (which is completely broken). If you have a phone, tablet, computer, coffee maker, car or any other kind of device with Wifi functionality built after 2004, it is almost certainly guaranteed to support WPA2. KRACK can be used to decrypt - and on some devices also to manipulate - data sent over a WPA and WPA2 protected wifi network. ## How does it work? The exact technique behind KRACK is too complex to adequately explain in this briefing. If you are interested, we encourage you to read the [original paper](https://papers.mathyvanhoef.com/ccs2017.pdf). A highly compressed summary is that the WPA2 standard never explicitly specified that a certain encryption key must not be used more than once. WPA2 uses many changing encryption keys to operate and the same key will never be used during regular interactions between legitimate access points and clients. However, Mr. Vanhoef discovered that attackers could trick wireless clients into re-using old keys repeatedly or even using very weak encryption keys. This in turn makes it trivial to decrypt the transmitted data. This is a great example of a well-designed and well-tested security mechanism that fails because attackers use it in ways that its creators didn’t anticipate. ## What KRACK is not Despite of what has been reported by various news outlets, KRACK is not the end of WPA2. It is possible to fix the vulnerability without breaking compatibility with unpatched devices and all major vendors are currently working on patches. KRACK also does not reveal the PSK (“wifi password”) used by the network. An attacker can thus not use the attack to authenticate with a WPA2 protected network. Merely traffic sent between a legitimate client and the access point can be decrypted and potentially manipulated. Lastly, KRACK can not be used to decrypt WPA2 protected traffic that was previously captured. The attack needs to constantly trick clients into reusing old encryption keys to work. This is also why - while definitions vary - many security researchers do not consider WPA2 itself to be broken. ## How can I protect myself? The risk a private user faces from KRACK has been overblown by media reports. The attacker needs to be in constant close proximity to the victim for the attack to succeed. Unless you present a highly valuable target to attackers, it is very unlikely that you will be targeted. Updating all of your devices as soon as patches become available should be adequate protection. The risk for corporate networks is significantly larger. Decrypting large amounts of corporate data traffic in hopes of stealing confidential information or access credentials appears to be a viable use for this attack vector. The attackers will still need to be in close physical proximity to the target company, thus significantly increasing the risk of detection and arrest compared to a remote cyber attack. Companies are encouraged to ensure all devices are updated in a timely manner. Lastly, using protocol-level encryption for all communications will completely mitigate KRACK. This means for example ensuring you are using HTTPS when loading websites or SMTPS, IMAPS or POPS when using email clients. Unfortunately, while these practices are used by most users when dealing with servers on the internet, many home or office servers do not use proper encryption and rely only on security provided by the closed Intranet. If your home or corporate network should have such services, we highly recommend that you upgrade or reconfigure them to use encryption for all communications. Topics: [High Tech](https://reflare.com/research/tag/high-tech) #### Share this [Share on Twitter](https://twitter.com/share?url=https://reflare.com/research/krack-wpa2-unforeseen-behaviour&text=KRACK,%20WPA2%20&%20Unforeseen%20Behaviour) [Share on Facebook](https://www.facebook.com/sharer/sharer.php?u=https://reflare.com/research/krack-wpa2-unforeseen-behaviour&t=KRACK,%20WPA2%20&%20Unforeseen%20Behaviour) [Share on LinkedIn](https://www.linkedin.com/shareArticle?mini=true&url=https://reflare.com/research/krack-wpa2-unforeseen-behaviour&t=KRACK,%20WPA2%20&%20Unforeseen%20Behaviour) - Recent - Topics - Archive Recent Topics - [Infosec Culture (113)](https://reflare.com/research/tag/infosec-culture) - [Anatomy of a Breach (60)](https://reflare.com/research/tag/anatomy-of-a-breach) - [Normal People and Infosec (42)](https://reflare.com/research/tag/normal-people-and-infosec) - [High Tech (31)](https://reflare.com/research/tag/high-tech) - [Infrastructure (21)](https://reflare.com/research/tag/infrastructure) - [Capture the Flag (8)](https://reflare.com/research/tag/capture-the-flag) See all Archive - [June 2026 (1)](https://reflare.com/research/archive/2026/06) - [May 2026 (1)](https://reflare.com/research/archive/2026/05) - [April 2026 (1)](https://reflare.com/research/archive/2026/04) - [March 2026 (1)](https://reflare.com/research/archive/2026/03) - [February 2026 (1)](https://reflare.com/research/archive/2026/02) - [January 2026 (1)](https://reflare.com/research/archive/2026/01) - [December 2025 (1)](https://reflare.com/research/archive/2025/12) - [November 2025 (1)](https://reflare.com/research/archive/2025/11) - [October 2025 (1)](https://reflare.com/research/archive/2025/10) - [September 2025 (1)](https://reflare.com/research/archive/2025/09) - [August 2025 (1)](https://reflare.com/research/archive/2025/08) - [July 2025 (1)](https://reflare.com/research/archive/2025/07) - [June 2025 (1)](https://reflare.com/research/archive/2025/06) - [May 2025 (1)](https://reflare.com/research/archive/2025/05) - [April 2025 (1)](https://reflare.com/research/archive/2025/04) - [March 2025 (1)](https://reflare.com/research/archive/2025/03) - [February 2025 (1)](https://reflare.com/research/archive/2025/02) - [January 2025 (1)](https://reflare.com/research/archive/2025/01) - [December 2024 (1)](https://reflare.com/research/archive/2024/12) - [November 2024 (1)](https://reflare.com/research/archive/2024/11) - [October 2024 (1)](https://reflare.com/research/archive/2024/10) - [September 2024 (1)](https://reflare.com/research/archive/2024/09) - [August 2024 (1)](https://reflare.com/research/archive/2024/08) - [July 2024 (1)](https://reflare.com/research/archive/2024/07) - [June 2024 (1)](https://reflare.com/research/archive/2024/06) - [April 2024 (2)](https://reflare.com/research/archive/2024/04) - [February 2024 (1)](https://reflare.com/research/archive/2024/02) - [January 2024 (1)](https://reflare.com/research/archive/2024/01) - [December 2023 (1)](https://reflare.com/research/archive/2023/12) - [November 2023 (1)](https://reflare.com/research/archive/2023/11) - [October 2023 (1)](https://reflare.com/research/archive/2023/10) - [September 2023 (1)](https://reflare.com/research/archive/2023/09) - [August 2023 (1)](https://reflare.com/research/archive/2023/08) - [July 2023 (1)](https://reflare.com/research/archive/2023/07) - [June 2023 (2)](https://reflare.com/research/archive/2023/06) - [May 2023 (2)](https://reflare.com/research/archive/2023/05) - [April 2023 (3)](https://reflare.com/research/archive/2023/04) - [March 2023 (4)](https://reflare.com/research/archive/2023/03) - [February 2023 (3)](https://reflare.com/research/archive/2023/02) - [January 2023 (5)](https://reflare.com/research/archive/2023/01) - [December 2022 (1)](https://reflare.com/research/archive/2022/12) - [November 2022 (2)](https://reflare.com/research/archive/2022/11) - [October 2022 (1)](https://reflare.com/research/archive/2022/10) - [September 2022 (11)](https://reflare.com/research/archive/2022/09) - [August 2022 (5)](https://reflare.com/research/archive/2022/08) - [July 2022 (1)](https://reflare.com/research/archive/2022/07) - [May 2022 (3)](https://reflare.com/research/archive/2022/05) - [April 2022 (1)](https://reflare.com/research/archive/2022/04) - [February 2022 (4)](https://reflare.com/research/archive/2022/02) - [January 2022 (3)](https://reflare.com/research/archive/2022/01) - [December 2021 (2)](https://reflare.com/research/archive/2021/12) - [November 2021 (3)](https://reflare.com/research/archive/2021/11) - [October 2021 (2)](https://reflare.com/research/archive/2021/10) - [September 2021 (1)](https://reflare.com/research/archive/2021/09) - [August 2021 (1)](https://reflare.com/research/archive/2021/08) - [June 2021 (1)](https://reflare.com/research/archive/2021/06) - [May 2021 (14)](https://reflare.com/research/archive/2021/05) - [February 2021 (1)](https://reflare.com/research/archive/2021/02) - [October 2020 (1)](https://reflare.com/research/archive/2020/10) - [September 2020 (1)](https://reflare.com/research/archive/2020/09) - [July 2020 (1)](https://reflare.com/research/archive/2020/07) - [June 2020 (1)](https://reflare.com/research/archive/2020/06) - [May 2020 (1)](https://reflare.com/research/archive/2020/05) - [April 2020 (2)](https://reflare.com/research/archive/2020/04) - [March 2020 (1)](https://reflare.com/research/archive/2020/03) - [February 2020 (1)](https://reflare.com/research/archive/2020/02) - [January 2020 (3)](https://reflare.com/research/archive/2020/01) - [December 2019 (1)](https://reflare.com/research/archive/2019/12) - [November 2019 (2)](https://reflare.com/research/archive/2019/11) - [October 2019 (3)](https://reflare.com/research/archive/2019/10) - [September 2019 (5)](https://reflare.com/research/archive/2019/09) - [August 2019 (2)](https://reflare.com/research/archive/2019/08) - [July 2019 (3)](https://reflare.com/research/archive/2019/07) - [June 2019 (3)](https://reflare.com/research/archive/2019/06) - [May 2019 (2)](https://reflare.com/research/archive/2019/05) - [April 2019 (3)](https://reflare.com/research/archive/2019/04) - [March 2019 (2)](https://reflare.com/research/archive/2019/03) - [February 2019 (3)](https://reflare.com/research/archive/2019/02) - [January 2019 (1)](https://reflare.com/research/archive/2019/01) - [December 2018 (3)](https://reflare.com/research/archive/2018/12) - [November 2018 (5)](https://reflare.com/research/archive/2018/11) - [October 2018 (4)](https://reflare.com/research/archive/2018/10) - [September 2018 (3)](https://reflare.com/research/archive/2018/09) - [August 2018 (3)](https://reflare.com/research/archive/2018/08) - [July 2018 (4)](https://reflare.com/research/archive/2018/07) - [June 2018 (4)](https://reflare.com/research/archive/2018/06) - [May 2018 (2)](https://reflare.com/research/archive/2018/05) - [April 2018 (4)](https://reflare.com/research/archive/2018/04) - [March 2018 (5)](https://reflare.com/research/archive/2018/03) - [February 2018 (3)](https://reflare.com/research/archive/2018/02) - [January 2018 (3)](https://reflare.com/research/archive/2018/01) - [December 2017 (2)](https://reflare.com/research/archive/2017/12) - [November 2017 (4)](https://reflare.com/research/archive/2017/11) - [October 2017 (3)](https://reflare.com/research/archive/2017/10) - [September 2017 (5)](https://reflare.com/research/archive/2017/09) - [August 2017 (3)](https://reflare.com/research/archive/2017/08) - [July 2017 (3)](https://reflare.com/research/archive/2017/07) - [June 2017 (4)](https://reflare.com/research/archive/2017/06) - [May 2017 (4)](https://reflare.com/research/archive/2017/05) - [April 2017 (2)](https://reflare.com/research/archive/2017/04) - [March 2017 (4)](https://reflare.com/research/archive/2017/03) - [February 2017 (2)](https://reflare.com/research/archive/2017/02) - [January 2017 (1)](https://reflare.com/research/archive/2017/01) - [December 2016 (1)](https://reflare.com/research/archive/2016/12) - [November 2016 (4)](https://reflare.com/research/archive/2016/11) - [October 2016 (2)](https://reflare.com/research/archive/2016/10) - [September 2016 (4)](https://reflare.com/research/archive/2016/09) - [August 2016 (5)](https://reflare.com/research/archive/2016/08) - [July 2016 (3)](https://reflare.com/research/archive/2016/07) - [June 2016 (5)](https://reflare.com/research/archive/2016/06) - [May 2016 (3)](https://reflare.com/research/archive/2016/05) - [April 2016 (4)](https://reflare.com/research/archive/2016/04) - [March 2016 (5)](https://reflare.com/research/archive/2016/03) - [February 2016 (4)](https://reflare.com/research/archive/2016/02) See all ### Subscribe by email #### About Reflare We help customers increase cyber resilience with the #1 hands-on IT security training platform. Our developer, administrator, and non-technical user training programs enhance user skills, fulfil your compliance needs, and contribute to developing more secure technologies. Legal - [Terms of Service](https://reflare.com/terms) - [Privacy Statement](https://reflare.com/privacy) - [Cookie Info](https://reflare.com/cookies) - [Copyright and Citation Enquiries](https://reflare.com/citation) - [Contact](https://reflare.com/contact) © 2026 Reflare Ltd, and/or its affiliates.   /   In business since 2009. ```json { "@context" : "https://schema.org", "@type" : "BlogPosting", "author" : { "@type" : "Person", "name" : "Reflare Research Team", "url" : "https://reflare.com/research/author/reflare-research-team" }, "dateModified" : "2023-11-21T13:37:46.865Z", "datePublished" : "2017-10-20T17:50:00.000Z", "headline" : "KRACK, WPA2 & Unforeseen Behaviour", "image" : [ "https://reflare.com/hubfs/Blog%20image%20in%20post/KRACK%2c%20WPA2%20&%20Unforeseen%20Behaviour.png" ], "mainEntityOfPage" : { "@id" : "https://reflare.com/research/krack-wpa2-unforeseen-behaviour", "@type" : "WebPage" }, "publisher" : { "@type" : "Organization", "logo" : { "@type" : "ImageObject", "url" : "https://reflare.com/hubfs/Reflare%20website%20images/Reflare%20Logos/logo.png" }, "name" : "Reflare" } } ```