After presenting our work at Real World Crypto 2018 [1] and seeing the enormous press coverage, we want to get two things straight: 1. Most described weaknesses are only exploitable by the malicious server or by knowing a large secret number and thereby the protocols are still very secure (what we wrote in the paper but some newspapers did not adopt) and 2. we see ways to enhance the WhatsApp protocol without breaking its features.
We are of course very happy that our research reached so many people and even though IT security and cryptography are often hard to understand for outsiders, Andy Greenberg [2], Patrick Beuth [3] and other journalists [4,5,6,7,8] wrote articles that were understandable on the one hand and very accurate and precise on the other hand. In contrast to this, we also saw some inaccurate articles [9,10] that fanned fear and greatly diverged in their description from what we wrote in our paper. We expected this from the boulevard press in Germany and therefore asked them to stick to the facts when they were contacting us. But none of the worst two articles' [9,10] authors contacted us in advance. Since our aim was never to blame any application or protocol but rather we wanted to encourage the developers to enhance the protocols, it contradicts our aim that WhatsApp and Signal are partially declared attackable by "anyone" "easily" [9,10].
Against this background, we understand Moxie's vexation about certain headlines that were on the Internet in the last days [11]. However, we believe that the ones who understand the weaknesses, comprehend that only the malicious server can detectably make use of them (in WhatsApp) or the secret group ID needs to be obtained from a member (in Signal). As such, we want to make clear that our paper does not primarily focus on the description of weaknesses but presents a new approach for analyzing and evaluating the security of group instant messaging protocols. Further we propose measures to enhance the analyzed protocols. The description of the protocols' weaknesses is only one part of the evaluation of our analysis approach and thereby of the investigation of real world protocols. This is the scientific contribution of our paper. The practical contribution of the analyzed messengers, which is the communication confidentiality for billion users (in most cases), is great and should be noted. Therefore we believe that being Signal, WhatsApp, or Threema by applying encryption to all messages and consequently risking research with negative results is much better than being a messenger that does not encrypt group messages end-to-end at all. We do not want to blame messengers that are far less secure (read Moxie's post [11] if you are interested).
Finally we want note that applying security measures according to the ticket approach (as we call it in the paper [12]) to the invitation links would solve the issues that Facebook's security head mentioned in his reply [13] on our findings. To our knowledge, adding authenticity to group update messages would not affect invitation links: If no invitation link was generated for a group, group members should only accept joining users if they were added by an authentic group update message. As soon as a group invitation link was generated, all joining users would need to be accepted as new group members with the current design. However there are plenty ways how WhatsApp could use invitation links without endowing the server with the power to manage groups without the group admins' permission:
One approach would be generating the invitation links secretly and sharing them without the knowledge of the server. An invitation link could then contain a secret ticket for the group and the ID of the group. As soon as a user, who received the link, wants to join the group, she can request the server with the group ID to obtain all current group members. The secret ticket can now be sent to all existing group members encrypted such that the legitimate join can be verified.
Of course this would require engineering but the capability of WhatsApp, shipping drastic protocol updates, can be assumed since they applied end-to-end encryption in the first place.
[1] https://www.youtube.com/watch?v=i5i38WlHfds
[2] https://www.wired.com/story/whatsapp-security-flaws-encryption-group-chats/
[3] http://www.spiegel.de/netzwelt/apps/whatsapp-gruppenchats-schwachstelle-im-verschluesselungs-protokoll-a-1187338.html
[4] http://www.sueddeutsche.de/digital/it-sicherheit-wie-fremde-sich-in-whatsapp-gruppenchats-einladen-koennen-1.3821656
[5] https://techcrunch.com/2018/01/10/security-researchers-flag-invite-bug-in-whatsapp-group-chats/
[6] http://www.telegraph.co.uk/technology/2018/01/10/whatsapp-bug-raises-questions-group-message-privacy/
[7] http://www.handelsblatt.com/technik/it-internet/verschluesselung-umgangen-forscher-finden-sicherheitsluecke-bei-whatsapp/20836518.html
[8] https://www.heise.de/security/meldung/WhatsApp-und-Signal-Forscher-beschreiben-Schwaechen-verschluesselter-Gruppenchats-3942046.html
[9] https://www.theinquirer.net/inquirer/news/3024215/whatsapp-bug-lets-anyone-easily-infiltrate-private-group-chats
[10] http://www.dailymail.co.uk/sciencetech/article-5257713/WhatsApp-security-flaw-lets-spy-private-chats.html
[11] https://news.ycombinator.com/item?id=16117487
[12] https://eprint.iacr.org/2017/713.pdf
[13] https://twitter.com/alexstamos/status/951169036947107840
Further articles:
- Matthew Green's blog post: https://blog.cryptographyengineering.com/2018/01/10/attack-of-the-week-group-messaging-in-whatsapp-and-signal/
- Schneier on Security: https://www.schneier.com/blog/archives/2018/01/whatsapp_vulner.html
- Bild: http://www.bild.de/digital/smartphone-und-tablet/whatsapp/whatsapp-sicherheitsluecke-in-gruppenchats-54452080.bild.html
- Sun: https://www.thesun.co.uk/tech/5316110/new-whatsapp-bug-how-to-stay-safe/
We are of course very happy that our research reached so many people and even though IT security and cryptography are often hard to understand for outsiders, Andy Greenberg [2], Patrick Beuth [3] and other journalists [4,5,6,7,8] wrote articles that were understandable on the one hand and very accurate and precise on the other hand. In contrast to this, we also saw some inaccurate articles [9,10] that fanned fear and greatly diverged in their description from what we wrote in our paper. We expected this from the boulevard press in Germany and therefore asked them to stick to the facts when they were contacting us. But none of the worst two articles' [9,10] authors contacted us in advance. Since our aim was never to blame any application or protocol but rather we wanted to encourage the developers to enhance the protocols, it contradicts our aim that WhatsApp and Signal are partially declared attackable by "anyone" "easily" [9,10].
Against this background, we understand Moxie's vexation about certain headlines that were on the Internet in the last days [11]. However, we believe that the ones who understand the weaknesses, comprehend that only the malicious server can detectably make use of them (in WhatsApp) or the secret group ID needs to be obtained from a member (in Signal). As such, we want to make clear that our paper does not primarily focus on the description of weaknesses but presents a new approach for analyzing and evaluating the security of group instant messaging protocols. Further we propose measures to enhance the analyzed protocols. The description of the protocols' weaknesses is only one part of the evaluation of our analysis approach and thereby of the investigation of real world protocols. This is the scientific contribution of our paper. The practical contribution of the analyzed messengers, which is the communication confidentiality for billion users (in most cases), is great and should be noted. Therefore we believe that being Signal, WhatsApp, or Threema by applying encryption to all messages and consequently risking research with negative results is much better than being a messenger that does not encrypt group messages end-to-end at all. We do not want to blame messengers that are far less secure (read Moxie's post [11] if you are interested).
Finally we want note that applying security measures according to the ticket approach (as we call it in the paper [12]) to the invitation links would solve the issues that Facebook's security head mentioned in his reply [13] on our findings. To our knowledge, adding authenticity to group update messages would not affect invitation links: If no invitation link was generated for a group, group members should only accept joining users if they were added by an authentic group update message. As soon as a group invitation link was generated, all joining users would need to be accepted as new group members with the current design. However there are plenty ways how WhatsApp could use invitation links without endowing the server with the power to manage groups without the group admins' permission:
One approach would be generating the invitation links secretly and sharing them without the knowledge of the server. An invitation link could then contain a secret ticket for the group and the ID of the group. As soon as a user, who received the link, wants to join the group, she can request the server with the group ID to obtain all current group members. The secret ticket can now be sent to all existing group members encrypted such that the legitimate join can be verified.
Of course this would require engineering but the capability of WhatsApp, shipping drastic protocol updates, can be assumed since they applied end-to-end encryption in the first place.
[1] https://www.youtube.com/watch?v=i5i38WlHfds
[2] https://www.wired.com/story/whatsapp-security-flaws-encryption-group-chats/
[3] http://www.spiegel.de/netzwelt/apps/whatsapp-gruppenchats-schwachstelle-im-verschluesselungs-protokoll-a-1187338.html
[4] http://www.sueddeutsche.de/digital/it-sicherheit-wie-fremde-sich-in-whatsapp-gruppenchats-einladen-koennen-1.3821656
[5] https://techcrunch.com/2018/01/10/security-researchers-flag-invite-bug-in-whatsapp-group-chats/
[6] http://www.telegraph.co.uk/technology/2018/01/10/whatsapp-bug-raises-questions-group-message-privacy/
[7] http://www.handelsblatt.com/technik/it-internet/verschluesselung-umgangen-forscher-finden-sicherheitsluecke-bei-whatsapp/20836518.html
[8] https://www.heise.de/security/meldung/WhatsApp-und-Signal-Forscher-beschreiben-Schwaechen-verschluesselter-Gruppenchats-3942046.html
[9] https://www.theinquirer.net/inquirer/news/3024215/whatsapp-bug-lets-anyone-easily-infiltrate-private-group-chats
[10] http://www.dailymail.co.uk/sciencetech/article-5257713/WhatsApp-security-flaw-lets-spy-private-chats.html
[11] https://news.ycombinator.com/item?id=16117487
[12] https://eprint.iacr.org/2017/713.pdf
[13] https://twitter.com/alexstamos/status/951169036947107840
Further articles:
- Matthew Green's blog post: https://blog.cryptographyengineering.com/2018/01/10/attack-of-the-week-group-messaging-in-whatsapp-and-signal/
- Schneier on Security: https://www.schneier.com/blog/archives/2018/01/whatsapp_vulner.html
- Bild: http://www.bild.de/digital/smartphone-und-tablet/whatsapp/whatsapp-sicherheitsluecke-in-gruppenchats-54452080.bild.html
- Sun: https://www.thesun.co.uk/tech/5316110/new-whatsapp-bug-how-to-stay-safe/
Related word
- Hack Tools For Ubuntu
- Hacking Tools For Kali Linux
- Pentest Tools Download
- World No 1 Hacker Software
- Hacking Tools For Windows Free Download
- Pentest Tools Open Source
- Pentest Reporting Tools
- Best Pentesting Tools 2018
- Easy Hack Tools
- Hacker Tool Kit
- Bluetooth Hacking Tools Kali
- Hack Tools Online
- Hack Tools Pc
- Ethical Hacker Tools
- Hacker Tools Software
- Hacking Tools For Windows 7
- Hack Tools For Ubuntu
- Pentest Tools Online
- Hacking Tools Online
- Pentest Tools Find Subdomains
- Hack Tools For Pc
- Hacking Tools Hardware
- Hacker Tools List
- Install Pentest Tools Ubuntu
- Hacker Tools For Pc
- Hack Tools For Ubuntu
- Hacker Tools For Windows
- Pentest Tools Framework
- Hacks And Tools
- Pentest Tools Framework
- World No 1 Hacker Software
- Pentest Automation Tools
- Pentest Tools Subdomain
- Hacking Tools For Windows Free Download
- Install Pentest Tools Ubuntu
- Hacking Tools Mac
- Hack Tools 2019
- Hacker Tool Kit
- Hack Tool Apk
- Hacking Tools For Pc
- Pentest Recon Tools
- Pentest Tools Url Fuzzer
- Hacker Tools Apk Download
- Hacker Tools
- Hacker Tools For Ios
- Hacker Tools Linux
- Hacker Tools Hardware
- Hackers Toolbox
- Hacker Tools List
- Top Pentest Tools
- Hacker Techniques Tools And Incident Handling
- Pentest Tools Kali Linux
- Github Hacking Tools
- Pentest Tools Windows
- Computer Hacker
- Tools For Hacker
- Usb Pentest Tools
- Hacker Tools Free
- New Hacker Tools
- Hacker Tools Linux
- Hacks And Tools
- Hack Tools Github
- Pentest Tools Apk
- Computer Hacker
- Pentest Automation Tools
- Pentest Reporting Tools
- Usb Pentest Tools
- Hack Tools
- Hack Tools For Pc
- Hack Tools Github
- Pentest Tools Open Source
- Kik Hack Tools
No hay comentarios:
Publicar un comentario