Dropbox 在 2012 的時候曾經傳出被入侵盜走六百九十萬筆個人資料。結果最近媒體發現[1],其實是被偷走 68,680,741 筆,其中31,865,280 組密碼使用 bcrypt hashing 加密,而另外的36,815,461組密碼則使用SHA1 hashing 加密。「我被黑了嗎?」(Have I been pwned[2]) 的站長 Troy Hunt[3] 拿到這批資料,驗證[4]之後確定是 Dropbox 被偷走得資料、不是假資料。

這些資料包含電子郵件與密碼,雖然這些密碼是被加密過,但是還是可能被破解猜出來。若沒有用不同密碼的習慣,別人就可能有機會用同樣帳號密碼登入不同的服務。而這些資料除了某些熟門路的人拿的到,像是 LeakedSource[5] 也提供付費版 API[6] 供人取用受害者原始資料 (亦即加密後的密碼等資料)。

比較好的習慣是使用密碼管理軟體 (Password Manager) 與雙因素授權 (Two factor authentication, 2FA)[9]。

密碼管理軟體的基本功能就是幫你產生亂數密碼,自動登入等,所以你可輕易在不同服務間使用難破解的密碼。密碼管理器的選擇很多[7][8],我自己是使用 Lastpass[11],它在瀏覽器與 Android 平台上整合的很方便。而且價格是 12 USD 一年,相較其他軟體更為便宜,雖然目前服務的公司有提供免費帳號,但是我已經買了好幾年了。Lastpass 雖然在 2015 也被入侵過[12],不過由於安全設計得當,並沒有產生重大問題。

我每個月都會定期做一次 Lastpass security challenge[10],他會檢查密碼強度、是否重複使用密碼,以及類似 Have I been pwned[2]、LeakedSource[5] 的功能,會查找已知的受害者資料庫,提醒是否為高風險需要採取任何行動。

快選一個密碼管理器吧。 https://lastpass.com/f?4133426

同場加映: Password manager security papers | Wilders Security Forums – http://www.wilderssecurity.com/threads/password-manager-security-papers.365724/

  • “Password Managers: Risks, Pitfalls, and Improvements” (2014)

    We study the security of popular password managers and their policies on automatically filling in passwords in web pages. We examine browser built-in password managers, mobile password managers, and 3rd party managers. We show that there are significant differences in autofill policies among password managers. Many autofill policies can lead to disastrous consequences where a remote network attacker can extract multiple passwords from the user’s password manager without any interaction with the user. We experiment with these attacks and with techniques to enhance the security of password managers. We show that our enhancements can be adopted by existing managers.

  • “Protecting Users Against XSS-based Password Manager Abuse” (2014)

    To ease the burden of repeated password authentication on multiple sites, modern Web browsers provide password managers, which offer to automatically complete password fields on Web pages, after the password has been stored once. Unfortunately, these managers operate by simply inserting the clear-text password into the document’s DOM, where it is accessible by JavaScript. Thus, a successful Cross-site Scripting attack can be leveraged by the attacker to read and leak password data which has been provided by the password manager. In this paper, we assess this potential threat through a thorough survey of the current password manager generation and observable characteristics of password fields in popular Web sites. Furthermore, we propose an alternative password manager design, which robustly prevents the identified attacks, while maintaining compatibility with the established functionality of the existing approaches.

  • “Vulnerability and Risk Analysis of Two Commercial Browser and Cloud Based Password Managers” (2013)

    Web users are confronted with the daunting challenges of managing more and more passwords to protect their valuable assets on different online services. Password manager is one of the most popular solutions designed to address such challenges by saving users’ passwords and later auto-filling the login forms on behalf of users. All the major browser vendors have provided password manager as a built-in feature; third-party vendors have also provided many password managers. In this paper, we analyze the security of two very popular commercial password managers: LastPass and RoboForm. Both of them are Browser and Cloud based Password Managers (BCPMs), and both of them have millions of active users worldwide. We investigate the security design and implementation of these two BCPMs with the focus on their underlying cryptographic mechanisms. We identify several critical, high, and medium risk level vulnerabilities that could be exploited by different types of attackers to break the security of these two BCPMs. Moreover, we provide some general suggestions to help improve the security design of these and similar BCPMs. We hope our analysis and suggestions could also be valuable to other cloud-based data security products and research.

  • “Automated Password Extraction Attack on Modern Password Managers” (2013)

    To encourage users to use stronger and more secure passwords, modern web browsers offer users password management services, allowing users to save previously entered passwords locally onto their hard drives. We present Lupin, a tool that automatically extracts these saved passwords without the user’s knowledge. Lupin allows a network adversary to obtain passwords as long as the login form appears on a non-HTTPS page. Unlike existing password sniffing tools, Lupin can obtain passwords for websites users are not visiting. Furthermore, Lupin can extract passwords embedded in login forms with a destination address served in HTTPS. To determine the number of websites vulnerable to our attack, we crawled the top 45,000 most popular websites from Alexa’s top website list and discovered that at least 28% of these sites are vulnerable. To further demonstrate the feasibility of our attack, we tested Lupin under controlled conditions using one of the authors’ computers. Lupin was able to extract passwords from 1,000 websites in less than 35 seconds. We suggest techniques for web developers to protect their web applications from attack, and we propose alternative designs for a secure password manager.

  • “Keys to the Cloud: Formal Analysis and Concrete Attacks on Encrypted Web Storage” (2013)

    To protect sensitive user data against server-side attacks, a number of security-conscious web applications have turned to client-side encryption, where only encrypted user data is ever stored in the cloud. We formally investigate the security of a number of such applications, including password managers, cloud storage providers, an e-voting website and a conference management system. We find that their security relies on both their use of cryptography and the way it combines with common web security mechanisms as implemented in the browser. We model these applications using the WebSpi web security library for ProVerif, we discuss novel attacks found by automated formal analysis, and we propose robust countermeasures.

  • “On The Security of Password Manager Database Formats” (2012)

    Password managers are critical pieces of software relied upon by users to securely store valuable and sensitive information, from online banking passwords and login credentials to passport- and social security numbers. Surprisingly, there has been very little academic research on the security these applications provide.
    This paper presents the first rigorous analysis of storage formats used by popular password managers. We define two realistic security models, designed to represent the capabilities of real-world adversaries. We then show how specific vulnerabilities in our models allow an adversary to implement practical attacks. Our analysis shows that most password manager database formats are broken even against weak adversaries.

  • From Web-based Attacks on Host-Proof Encrypted Storage (2012):

    Cloud-based storage services, such as Wuala, and password managers, such as LastPass, are examples of so-called host-proof web applications that aim to protect users from attacks on the servers that host their data. To this end, user data is encrypted on the client and the server is used only as a backup data store. Authorized users may access their data through client-side software, but for ease of use, many commercial applications also offer browser-based interfaces that enable features such as remote access, form-filling, and secure sharing.
    We describe a series of web-based attacks on popular host-proof applications that completely circumvent their cryptographic protections. Our attacks exploit standard web application vulnerabilities to expose flaws in the encryption mechanisms, authorization policies, and key management implemented by these applications. Our analysis suggests that host-proofing by itself is not enough to protect users from web attackers, who will simply shift their focus to flaws in client-side interfaces.

利益揭露: lastpass 的邀請連結是我的個人 premium referral link.

[1] Hackers Stole Account Details for Over 60 Million Dropbox Users | Motherboard – http://motherboard.vice.com/read/hackers-stole-over-60-million-dropbox-accounts
[2] Have I been pwned? Check if your email has been compromised in a data breach – https://haveibeenpwned.com/
[3] Troy Hunt, a Microsoft Regional Director and Most Valuable Professional awardee for Developer Security – https://haveibeenpwned.com/About
[4] Troy Hunt: The Dropbox hack is real – https://www.troyhunt.com/the-dropbox-hack-is-real/
[5] Find the source of your leaks – https://www.leakedsource.com/
[6] LeakedSource API Purchase – https://www.leakedsource.com/api/purchase
[7] Password Managers Compared http://www.howtogeek.com/?p=240255
[8] Best Password Manager http://www.asecurelife.com/dashlane-vs-lastpass-vs-1password-vs-roboform-vs-keepass/
[9] https://en.wikipedia.org/wiki/Multi-factor_authentication
[10] https://blog.lastpass.com/tag/lastpass-security-challenge/
[11] https://lastpass.com/f?4133426
[12] LastPass Hacked http://lifehacker.com/lastpass-hacked-time-to-change-your-master-password-1711463571

OpenStreetMap 從 2012/09/12 後的資料,是使用 ODbL (Open Database License)[1] 散布。ODbL 條款[2][3][4]有寬鬆的授權模式 (permissive license)、 Copyleft 授權等特性,這些特性影響到利用 OSM 為基礎開發的其他作品是否也該以 ODbL 授權方式 (條款 4.4 節) 再次散布,或是只要聲明資料來自使用 ODbL 的 OSM 資料庫 (條款 4.3 節)。

而作品的區分方式分為

  • Produced Work 產製作品
  • Derived Work 衍生作品

例如把 OSM 輸出成圖檔或是紙本地圖,這即是「產製作品」。如果是直接改造原始資料庫,則為「衍生作品」。

給行動裝置用的向量圖資 (Garmin img 或 MapsForge[9]) 是一個模糊的地帶,因為實際上地圖並非以圖檔格式 (raster graphic) 散布,而是將原始 OSM 資料庫轉換成另外一種資料庫型態散布。但是由於這些向量圖檔的主要用途仍是離線顯示地圖,在 OSM 社群的討論[8][9]上,是被認可為「產製作品」[6]。除非新增額外的資訊到資料庫或增修其向量圖檔,或將其作為資料庫使用,則會被視為「衍生作品」[11]。

所以如果你散布的是未經過增修的向量圖資則請按照 4.3 節規定,在授權處說明

並請於輸出註明 “© OpenStreetMap contributors” [12]

[1] Open Database License – OpenStreetMap Wiki – https://wiki.openstreetmap.org/wiki/Open_Database_License
[2] Open Database License (ODbL) v1.0 | Open Data Commons – http://opendatacommons.org/licenses/odbl/1-0/
[3] 20121120-ODbL-1.0非官方正體中文翻譯 | Lu-six Person’s Notes – http://lucien.cc/?p=2358
[4] 20121120-DbCL-1.0非官方正體中文翻譯 | Lu-six Person’s Notes – http://lucien.cc/?p=2360
[5] 20121018-從開源軟體到開放資料-論 Open Database License v1.0 | Lu-six Person’s Notes – http://lucien.cc/?p=2348
[6] Licence/Community Guidelines/Produced Work – Guideline – OpenStreetMap Foundation Wiki – http://wiki.osmfoundation.org/wiki/Licence/Community_Guidelines/Produced_Work_-_Guideline
[7] Open Data License/Produced Work – Guideline – OpenStreetMap Wiki – https://wiki.openstreetmap.org/wiki/Open_Data_License/Produced_Work_-_Guideline
[8] [OSM-legal-talk] Garmin maps and license – https://lists.openstreetmap.org/pipermail/legal-talk/2016-February/008382.html
[9] Selling routable OSM maps for garmin – OSM Help – http://help.openstreetmap.org/questions/48251/selling-routable-osm-maps-for-garmin
[10] 台灣 MapsForge 圖資檔案 – osmtw.hackpad.com – https://osmtw.hackpad.com/%E5%8F%B0%E7%81%A3-MapsForge-%E5%9C%96%E8%B3%87%E6%AA%94%E6%A1%88-tcm2Owggcqb
[11] Legal FAQ – OpenStreetMap Wiki – https://wiki.openstreetmap.org/wiki/Legal_FAQ#3c._If_I_make_something_with_OSM_data.2C_do_I_now_have_to_apply_your_license_to_my_whole_work.3F
[12] Legal FAQ – OpenStreetMap Wiki – https://wiki.openstreetmap.org/wiki/Legal_FAQ#3._Using

先前注意到中國 CA 憑證簽發單位[1]可能會濫發簽章,而導致中間人攻擊等風險,而過去也的確發生過一些隨意簽發 Google 網域簽章的案例[2]。最近看到 Mozilla 討論 WoSign 的安全疑慮[3][4],如濫發 github.com 簽章等。決定把中國的 CA 全數移除。

RevokeChinaCerts[5] 可以

  • 移除 Network Security Service 中的設定。 (需要裝 libnss3-tools)
  • 移除全系統的 default internet SSL certificate trustchains. (ca-certificates)

修正了 Linux 版本的的問題[6]。

另外發現 Ubuntu 還沒有做 ArchLinux 上那種簡易黑名單簽章管理機制[7]。

[1] http://blog.nutsfactory.net/tag/cnnic/
[2] http://bit.ly/2bBnm9g
[3] Mozilla 在考慮移除 WoSign 的 CA Root http://bit.ly/2bwXAbU
[4] Incidents involving the CA WoSign – http://bit.ly/2bOoHx8
[5] https://github.com/chengr28/RevokeChinaCerts
[6] http://bit.ly/2bymDKF
[7] Managing SSL certificates – http://bit.ly/2bFAoUX

FESCo[1]投票決定[4],預定在 2016/11/15 [2]發布的 Fedora 25 [3]預期將會使用 Wayland 取代 X.Org 圖形系統,效能看起來稍須改進[8]。配合新的 GTK 3.22[5],整合[8]平板電腦所需的 pad events[7] 支援了。

同場加映: 目前在 Ubuntu 16.10 上面測試 Unity8 + Mir[9],雖然還有些問題,但是可用性已經相當高。看起來 Linux Desktop 環境揚棄 X.org 改用新的 Wayland/Mir 圖形系統的時間就在今年後了。

[1]: https://fedoraproject.org/wiki/Fedora_Engineering_Steering_Committee “FESCo is the Fedora Engineering Steering Committee”
[2]: https://fedoraproject.org/wiki/Releases/25/Schedule “Releases/25/Schedule – FedoraProject”
[3]: https://fedoraproject.org/wiki/Releases/25/ChangeSet “Releases/25/ChangeSet – FedoraProject”
[4]: https://fedorahosted.org/fesco/ticket/1615 “#1615 (Consider Wayland by default for F25) – FESCo”
[5]: https://wiki.gnome.org/ThreePointTwentyone/ReleaseNotes “ThreePointTwentyone/ReleaseNotes – GNOME Wiki!”
[6]: https://blogs.gnome.org/carlosg/2016/08/24/wayland-%E2%99%A1-drawing-tablets/ “Wayland ♡ drawing tablets – Carlos Garnacho”
[7]: https://blogs.gnome.org/carlosg/2016/04/06/gtk-wayland-tablet-support-is-merged/ “GTK+ Wayland tablet support is merged – Carlos Garnacho”
[8]: http://www.phoronix.com/scan.php?item=f25-alpha-wayland&num=1&page=article “Trying Out Fedora 25 With Wayland, Early Benchmarks Included – Phoronix”
[9]: https://www.youtube.com/watch?v=cWLgY-2bZZM “Ubuntu 16.10 Unity 8 / Mir – Current State – YouTube”

Linux 二十五週年了。OMG Ubuntu 的圖[1]提供了一些數據,被移植到各種不同的裝置產品[2][3]上。根據 Linux Foundation 的資料[5][6],過去十一年以來自 1300 間公司、超過13500位開發者參與核心開發,Intel 超越 RedHat 是貢獻第一名的公司。由於核心開發者深受企業需求,只有 7.7% 開發者非企業員工,且逐年下降。

不知道讀者在這四分之一的世紀中,參與過幾個 Linux 產品開發呢?
[1] http://www.omgubuntu.co.uk/2016/08/happy-25th-birthday-linux
[2] http://www.omgubuntu.co.uk/2016/08/25-awesome-unexpected-things-powered-linux
[3] https://insights.ubuntu.com/2016/08/25/25-linux-devices-to-celebrate-25-years-of-linux/
[4] https://medium.freecodecamp.com/linux-is-25-yay-lets-celebrate-with-25-rad-facts-about-linux-c8d8ac30076d
[5] http://ht.ly/iWhw303FMmo
[6] http://ht.ly/1Tm9303FMlT

台灣幾個大的電信商都有電話會議服務[1][2][3],這是最穩定保險的機制,但是成本高昂。四十個人兩個小時的會議,費用將近兩萬五千台幣。

有 VoIP 能力的網路聊天室服務人數有上限,Google Hangout[4] 免費版十人、企業板二十五人、Skyep 二十五人[5] 人。

而 IM 類型的
Facebook Messenger – 50 人。
LINE – 200 人。
WeChat – 8 人。

另外網路上的免費語音電話如 Free Conference Call International[9][10],如果使用電話撥打接入,費用則由撥打者支付。但如果使用 Android 手機,可以使用免費 VoIP 撥打接入。

[1] 中華電信會議電話服務 Conference Service – https://www.twgate.net/concall/page_01_tel.php
[2] 台灣大哥大商務服務_會議電話_產品服務 – http://www.twmsolution.com/svc/voice/vo_20150127_355110.html
[3] 遠傳雲端電話會議服務 – http://www.fetnet.net/cs/Satellite/EBU/ebAudioCon
[4] Hangouts system requirements on your computer – Google+ Help – https://support.google.com/plus/answer/1216376?hl=en
[5] https://www.skype.com/en/features/group-calls/
[6] LINE Introduces New Group Voice Call Feature | LINE Corporation | News – https://linecorp.com/en/pr/news/en/2016/1268
[7] David Marcus – Really excited to announce the global roll out of… – https://www.facebook.com/photo.php?fbid=10156931343110195&set=a.489597915194.389572.800665194&type=3&theater
[8] 多人通話人數上限為9人 – https://help.wechat.com/cgi-bin/micromsg-bin/oshelpcenter?t=help_center/topic_detail&opcode=2&plat=android&lang=en&id=1208117b2mai141125A7rUvi&Channel=helpcenter
[9] Free Conference Call International – https://www.freeconferencecall.com/
[10] https://www.freeconferencecall.com/free-international-conference-call/Default.aspx?lang=tw&altlang=zh-tw
[11] Conference Call Apps for iPhone & Android | FreeConferenceCall.com – https://www.freeconferencecall.com/apps
[12] FCC-Dialer on the App Store – https://itunes.apple.com/us/app/fcc-dialer/id350911070?mt=8
[13] Free Conference Call – Google Play Android 應用程式 – https://play.google.com/store/apps/details?id=com.freeconferencecall.fccmeetingclient