Reception and criticism of WhatsApp security and privacy features

Messaging with WhatsApp
WhatsApp Timeline
Feb 24, 2009 Jan Koum incorporates WhatsApp in California.[1]
Oct 2009 Brian Acton persuades five ex-Yahoo! friends to invest $250,000 in seed funding, and is granted co-founder status.[1]
Aug 2009 WhatsApp 2.0 is released on the App Store for the iPhone.[2]
Dec 2009 WhatsApp for the iPhone is updated to send photos.[1]
Aug 2010 WhatsApp support for Android OS is added.[3]
Jan 21, 2011 WeChat, a messenger app, is founded.[4] It eventually becomes very popular in China.
Apr 2011 In Series A round, WhatsApp founders agree to take $7 million from Sequoia Capital on top of their $250,000 seed funding, after months of negotiation with Sequoia partner Jim Goetz.[1]
May 2011 SnapChat, a competing photo messaging app, is founded.[5]
Jan 6, 2012 An unknown hacker publishes a website that makes it possible to change the status of an arbitrary WhatsApp user, as long as the phone number was known.[6][7]
Aug 2012 The WhatsApp support staff announce that messages were encrypted in the "latest version" of the WhatsApp software for iOS and Android (but not BlackBerry, Windows Phone, and Symbian), without specifying the cryptographic method.[8]
Feb 2013 WhatsApp's user base swells to about 200 million active users and its staff to 50.[1]
Jul 2013 Sequoia invests another $50 million in Series B round, valuing WhatsApp at $1.5 billion.[9]
Jul 16, 2013 WhatsApp goes free, with an annual subscription fee of $1 after the first year.[10][11]
Aug 2013 Telegram, a cloud-based instant messaging service, launches.[12]
Aug 2013 WhatsApp introduces voice messaging.[13]
Feb 19, 2014 Facebook announces its acquisition of WhatsApp for US$19 billion, its largest acquisition to date.[14] Facebook pays $4 billion in cash, $12 billion in Facebook shares, and an additional $3 billion in restricted stock units granted to WhatsApp's founders.[15]
Mar 2014 Someone discovers a vulnerability in WhatsApp encryption on the Android application that allows another app to access and read all of a user’s chat conversations within it.[16]
Nov 2014 WhatsApp introduces a feature named Read Receipts, which alerts senders when their messages are read by recipients. Within a week, WhatsApp introduces an update allowing users to disable this feature so that message recipients do not send acknowledgements.[17]
Jan 21, 2015 WhatsApp launches WhatsApp Web, a web client which can be used through a web browser by syncing with the mobile device's connection.[18]
Jan 21, 2015 WhatsApp announces its policy on cracking down on 3rd-party clients, including WhatsApp+.[19] Users would not be able to use WhatsApp’s services at all until the third-party apps are uninstalled.[20]
Dec 2015 WhatsApp is briefly shut down in Brazil after it refuses to place wiretaps on certain WhatsApp accounts.[21] It is shut down in Brazil again on May 2016 and in July 2016.[22]
Jan 18, 2016 Jan Koum announces that WhatsApp will no longer charge its users a $1 annual subscription fee.[23][24] There is still no clear plan for monetizing WhatsApp.[25]
Mar 2016 Diego Dzodan, a Facebook executive, is arrested by Brazilian federal police after Facebook fails to turn over information from his WhatsApp messaging account into a judge's request for a drug trafficking investigation.[26]
Mar 2, 2016 WhatsApp introduces its document-sharing feature, initially allowing users to share PDF files with their contacts.[27]
Apr 5, 2016 WhatsApp and Open Whisper Systems announce that they finish adding end-to-end encryption to "every form of communication" on WhatsApp, and that users could now verify each other's keys.[28][29][30]
May 10, 2016 WhatsApp is introduced for both Windows and Mac operating systems.[31]
Sep 5, 2017 WhatsApp started external testing of an enterprise platform which enables companies to provide customer service to users at scale.[32] Airline KLM launches such a service.[33]

This article provides a detailed historic account of the reception and criticism of security and privacy features in the WhatsApp messaging service.

2011

On May 20, 2011, an unconfirmed security researcher from the Netherlands under the pseudonym "WhatsappHack" published, to the Dutch websites Tweakers.net and GeenStijl, a method by which WhatsApp accounts could be hijacked. The researcher noticed a flaw in the authentication process, which allowed the researcher to hijack an account by trying to login with another phone number and intercepting the verification SMS text message that, under specific conditions, remained in the outbox of the Symbian phone after the WhatsApp client would attempt to send it to itself. On Android, the verification message could be obtained through reading the "radio" with a tool named "logcat". The researcher would then copy and send the intercepted verification message to the real number of the phone, using an SMS gateway to spoof the "sender" phone number to the number the researcher tried to maliciously login with. This method worked, and WhatsApp issued a patch within one day after publication of the articles, to both the Android and Symbian clients. WhatsApp did have a security mechanism, by design, which would disable the account on the phone of the original owner of the phone number, when they had a WhatsApp account.[34][35][36]

In May 2011, another security hole was reported which left communication through WhatsApp susceptible to packet analysis. WhatsApp communications were not encrypted, and data was sent and received in plaintext, meaning messages could easily be read if packet traces were available.[37]

2012

In May 2012 security researchers noticed that new updates of WhatsApp no longer sent messages as plaintext,[38][39][40] but the cryptographic method implemented was subsequently described as "broken".[41][42] In August 2012 the WhatsApp support staff said that messages were encrypted in the "latest version" of the WhatsApp software for iOS and Android (but not BlackBerry, Windows Phone, and Symbian), without specifying the cryptographic method.[43]

On January 6, 2012, an unknown hacker published a website that made it possible to change the status of an arbitrary WhatsApp user, as long as the phone number was known. To make it work, it only required a restart of the app. According to the hacker, it was only one of many security problems in WhatsApp. On January 9, WhatsApp reported that it had resolved the problem, although the only measure actually taken was to block the website's IP address. As a reaction, a Windows tool was made available for download providing the same functionality. This problem has since been resolved in the form of an IP address check on currently logged-in sessions.[44][45]

German Tech site The H demonstrated how to use WhatsAPI to hijack any WhatsApp account on September 14, 2012.[46] Shortly after, a legal threat to WhatsAPI's developers was alleged, characterized by The H as "an apparent reaction" to security reports, and WhatsAPI's source code was taken down for some days.[47] The WhatsAPI team has since returned to active development.[48]

2013–2015

On March 31, 2013 the Saudi Arabian Communications and Information Technology Commission (CITC) issued a statement regarding possible measures against WhatsApp, among other applications, unless the service providers took serious steps to comply with monitoring and privacy regulations.[49]

In February 2014, the public authority for data privacy of the German state of Schleswig-Holstein advised against using WhatsApp, as the service lacked privacy protection such as end-to-end client side encryption technology.[50] WhatsApp started implementing end-to-end encryption in late 2014 and finished in April 2016.[28]

A major privacy and security problem has been the subject of a joint Canadian-Dutch government investigation. The primary concern was that WhatsApp required users to upload their mobile phone's entire address book to WhatsApp servers so that WhatsApp could discover who, among the users' contacts, was available via WhatsApp. While this was a fast and convenient way to quickly find and connect the user with contacts who were also using WhatsApp, it meant that their address book was then mirrored on the WhatsApp servers, including contact information for contacts who were not using WhatsApp. This information, which consisted solely of phone numbers without any additional information such as the name of the contact, was stored in hashed, though not salted, form.[51][52][53][54] Late 2015, the Dutch government released a press-statement claiming that WhatsApp had changed its hashing method, making it much harder to reverse, and thus now fully complies with all rules and regulations.[55]

A user does not need to send a friend request to send messages to another user, due to the contact discovery mentioned above.

In November 2014, WhatsApp introduced a feature named Read Receipts which alerts senders when their messages are read by recipients. Within a week, WhatsApp introduced an update allowing users to disable this feature so that message recipients do not send acknowledgements.[56] On December 1, 2014, Indrajeet Bhuyan and Saurav Kar, both 17 years old, demonstrated the WhatsApp Message Handler Vulnerability, which allows anyone to remotely crash WhatsApp just by sending a specially crafted message of 2kb in size. To escape the problem, the user who receives the specially crafted message has to delete his/her whole conversation and start a fresh chat, because opening the message keeps on crashing WhatsApp unless the chat is deleted completely.[57] In early 2015, after WhatsApp launched a web client that can be used from the browser, Bhuyan also found that it had two security issues that compromised user privacy: the WhatsApp Photo Privacy Bug and the WhatsApp Web Photo Sync Bug.[58][59]

In February 2015, a Dutch university student named Maikel Zweerink published an app that set out to prove that anyone could track a WhatsApp user's status and also keep an eye of their changing profile pictures, privacy settings or status messages regardless of their privacy settings.[60]

2016

On March 2, 2016, WhatsApp introduced its document-sharing feature, initially allowing users to share PDF files with their contacts.[61] However, WhatsApp's default state of automatically downloading attachments raised some concerns in the press about risk and security once support for document sharing expanded beyond PDF files.[62]

In August 2016, WhatsApp announced that it will start sharing account information with Facebook, consisting of the phone number of the account owner and aggregated analytical data. The address books and metadata of users are not shared. According to WhatsApp, this account information is shared to "track basic metrics about how often people use our services and better fight spam on WhatsApp. And by connecting your phone number with Facebook's systems, Facebook can offer better friend suggestions and show you more relevant ads if you have an account with them." This means that Facebook can target advertisements on the Facebook Platform better by making links between users based on the phone numbers, and make "friend suggestions" to its users based on WhatsApp's data. User data will not be shared with advertisers, and is only used internally on the Facebook services. WhatsApp emphasizes the content of user messages is still kept private thanks to its end-to-end encryption, which means WhatsApp cannot read the content of chats.[63][64] However, users are given the choice to opt out of sharing this data with Facebook for advertisement purposes.[65] In October 2016, Article 29 Working Party stated that it has serious concerns regarding the manner in which the information relating to the updated Terms of Service and Privacy Policy was provided to users and consequently about the validity of the users’ consent.[66]

From April 5, 2016, end-to-end encryption for all users' communications, including file transfers and voice calls, is supported for users of the latest client, encryption being enabled by default. It uses Curve25519 for key exchange, HKDF for generation of session keys (AES-256 in CBC mode for encryption and HMAC-SHA256 for integrity verification) and SHA512 for generating the two 30 digit fingerprints of both users' identity keys so they can verify each other as needed. Even the company would be unable to decrypt users' communications. Amnesty International and security professionals praised the move; the US Federal Bureau of Investigation criticised it as threatening the work of law enforcement.[67] Telegram, another messaging service, is reported by the BBC to be used by "Islamic State" extremists.[67]

WhatsApp is not the only messaging service that provides end-to-end encryption; among others, Threema, Wickr, Signal, Silent Phone, and Line also provide such encryption by default. iMessage and Viber provide it under special circumstances.[68][69] Telegram provides end-to-end encryption as an opt-in feature, but does not support end-to-end encrypted group messaging.[28]

As of April 5, 2016, WhatsApp has a score of 6 out of 7 points on the Electronic Frontier Foundation's "Secure Messaging Scorecard". It has received points for having communications encrypted in transit, having communications encrypted with keys the provider doesn't have access to, allowing users to verify contacts' identities, having past messages secure if the encryption keys are stolen, having completed a recent independent security audit, and having the security designs properly documented. It is missing a point because the code is not open to independent review.[70]

2017

On January 13, 2017, The Guardian reported that security researcher Tobias Boelter had found that WhatsApp's policy of forcing re-encryption of initially undelivered messages, without informing the recipient, constituted a serious loophole whereby WhatsApp could disclose, or be compelled to disclose, the content of these messages.[71] WhatsApp[72] and Open Whisper Systems[73] officials disagreed with this assessment. A follow-up article by Boelter himself explained in greater detail what he considered to be the specific vulnerability. This article has since been removed[74] by The Guardian due to the inaccuracies in Boelter’s representation of the facts. After complaints from 73 renowned security researchers[75], The Guardian was forced to substantially revise and correct their own articles as well. Therefore, in June 2017, The Guardian readers’ editor Paul Chadwick wrote that "The Guardian was wrong to report in January that the popular messaging service WhatsApp had a security flaw so serious that it was a huge threat to freedom of speech."[76]

"In a detailed review I found that misinterpretations, mistakes and misunderstandings happened at several stages of the reporting and editing process. Cumulatively they produced an article that overstated its case."

— Paul Chadwick, The Guardian[76]

Chadwick also noted that since the Guardian article, WhatsApp has been "better secured by the introduction of optional two-factor verification in February."[76] However, it is important to note that this feature was already introduced in public beta versions of WhatsApp as early as November 2016[77], which was months before The Guardian wrote about the alleged issue.

In October 2017, the German software company Open-Xchange criticised WhatApps and Slack for using proprietary software and stated plans to create an open source alternative.[78]

References

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  67. ↑ Lee, Micah (2 March 2015). "You Should Really Consider Installing Signal, an Encrypted Messaging App for iPhone". The Intercept. First Look Media. Retrieved 12 January 2016. Apple’s iMessage ... employs strong encryption, but only when communicating between two Apple devices and only when there is a proper data connection. Otherwise, iMessage falls back on insecure SMS messaging.
  68. ↑ "Requirements for enhanced security features". Viber Security FAQ. Viber. n.d. Retrieved 16 July 2016. Note that Viber for Windows Phone 8 will not support the new security features. It will continue to secure calls and messages through standard encryption methods.
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  70. ↑ Manisha, Ganguly (13 January 2017). "WhatsApp vulnerability allows snooping on encrypted messages". The Guardian. Retrieved 21 February 2017.
  71. ↑ Dan, Goodin (13 January 2017). "Reported "backdoor" in WhatsApp is in fact a feature, defenders say". Ars Technica. Retrieved 21 February 2017. WhatsApp does not give governments a "backdoor" into its systems and would fight any government request to create a backdoor. The design decision referenced in the Guardian story prevents millions of messages from being lost, and WhatsApp offers people security notifications to alert them to potential security risks. WhatsApp published a technical white paper on its encryption design and has been transparent about the government requests it receives, publishing data about those requests in the Facebook Government Requests Report.
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  75. 1 2 3 Chadwick, Paul (28 June 2017). "Flawed reporting about WhatsApp". The Guardian. Retrieved 6 October 2017.
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  77. ↑ https://www.theregister.co.uk/2017/10/12/openxchange_imap_chat_killer_app/
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