因為 Diablo II: Resurrected 的關係跑回來用 Windows 10,裝完 OS 後可以透過 GUI 關掉一堆隱私設定沒錯,但感覺應該是有人整理出來更方便的方法...
在「Awesome Windows privacy」這邊看到有工具可以做到,目前用的是「Windows-10-Hardening」這組,把 script 抓下來後用管理權限跑一次,接著重開機就好了...
看起來沒什麼大問題,之後應該都會在重灌後拿來用...
幹壞事是進步最大的原動力
因為 Diablo II: Resurrected 的關係跑回來用 Windows 10,裝完 OS 後可以透過 GUI 關掉一堆隱私設定沒錯,但感覺應該是有人整理出來更方便的方法...
在「Awesome Windows privacy」這邊看到有工具可以做到,目前用的是「Windows-10-Hardening」這組,把 script 抓下來後用管理權限跑一次,接著重開機就好了...
看起來沒什麼大問題,之後應該都會在重灌後拿來用...
Dropbox 也要搞自己的密碼管理器 Dropbox Passwords:「Dropbox Passwords coming soon for all users」。
看起來只要是 Dropbox 的付費方案就可以無限使用,而免費版的則是 50 組。從下載頁看起來目前在 PC 上只支援 Microsoft Windows 與 macOS,不支援 Linux:
Come back to this page on a PC with Windows 10 or a Mac with at least macOS Sierra 10.12 to get the Passwords desktop app.
How do I use the Android and iPhone password manager?
Once you sign in to the Passwords app, it automatically fills in your usernames and passwords so you can access frequently used apps and websites on your mobile device.
從示意圖看起來有整合瀏覽器,而加密技術的部份沒有講太多,只說是 zero-knowledge encryption,先觀望看看...
這次看到的是針對 TLS 實做上的問題產生的 Raccoon Attack,反正先取個名字就對了,原圖有點大張,設個 medium size 好了 XDDD:
Why is the attack called "Raccoon"?
Raccoon is not an acronym. Raccoons are just cute animals, and it is well past time that an attack will be named after them :)
先講影響的產品,首先是經常中槍的 F5,這次連 timing measurement 都不需要太準確就可以打穿:
In particular, several F5 products allow executing a special version of the attack, without the need for precise timing measurements.
OpenSSL 的部份因為從 1.0.2f 之後因為其他的 security issue 所以改善了實做方式,就不會受到這次的攻擊手法影響。
剛剛翻了一下 Ubuntu 上的的資料,看起來 16.04 (xenial
) 上的 OpenSSL 就已經是 1.0.2g 了,所以目前只要是有在 Ubuntu 支援的版本應該都不受影響:
OpenSSL assigned the issue CVE-2020-1968. OpenSSL does use fresh DH keys per default since version 1.0.2f (which made SSL_OP_SINGLE_DH_USE default as a response to CVE-2016-0701).
Firefox 直接拔了 DH 與 DHE 相關的 cipher suite,反正在這次攻擊手法出來前本來就已經計畫要拔掉:
Mozilla assigned the issue CVE-2020-12413. It has been solved by disabling DH and DHE cipher suites in Firefox (which was already planned before the Raccoon disclosure).
微軟的部份則是推更新出來:
Microsoft assigned the issue CVE-2020-1596. Please refer to the Microsoft Security Response Center portal.
回到攻擊手法,這次的問題是因為 DH 相關的實做造成的問題。
TLS 要求去掉 premaster secret 裡開頭的 0,造成會因為開頭的 0 數量不同而實做上就不會是 constant time,所以有了一些 side channel information 可以用:
Our Raccoon attack exploits a TLS specification side channel; TLS 1.2 (and all previous versions) prescribes that all leading zero bytes in the premaster secret are stripped before used in further computations. Since the resulting premaster secret is used as an input into the key derivation function, which is based on hash functions with different timing profiles, precise timing measurements may enable an attacker to construct an oracle from a TLS server.
然後一層一層堆,能夠知道 premaster secret 開頭是不是 0 之後,接下來因為 server side 會重複使用同一組 premaster secret,所以可以當作一個 oracle,試著去計算出更後面的位數:
This oracle tells the attacker whether a computed premaster secret starts with zero or not. For example, the attacker could eavesdrop ga sent by the client, resend it to the server, and determine whether the resulting premaster secret starts with zero or not.
Learning one byte from a premaster secret would not help the attacker much. However, here the attack gets interesting. Imagine the attacker intercepted a ClientKeyExchange message containing the value ga. The attacker can now construct values related to ga and send them to the server in distinct TLS handshakes. More concretely, the attacker constructs values gri*ga, which lead to premaster secrets gri*b*gab. Based on the server timing behavior, the attacker can find values leading to premaster secrets starting with zero. In the end, this helps the attacker to construct a set of equations and use a solver for the Hidden Number Problem (HNP) to compute the original premaster secret established between the client and the server.
所以針對這個攻擊手法的解法就是用「新鮮的」premaster secret (像是完全不重複使用),然後保留開頭的 0,不需要去掉。而 TLS 1.3 在定義的時候把這兩件事情都做了,所以不會受到影響:
Is TLS 1.3 also affected?
No. In TLS 1.3, the leading zero bytes are preserved for DHE cipher suites (as well as for ECDHE ones) and keys should not be reused.
另外在這邊提到的 Hidden Number Problem (HNP) 也是個不熟悉的詞彙,網站上有提到論文,也就是「Hardness of computing the most significant bits of secret keys in Diffie-Hellman and related schemes」這篇:
Given an oracle Oα(x) that on input x computes the k most significant bits of (α * gx mod p) , find α mod p.
是個離散對數類的問題,之後有空再來翻一翻好了。
收到 SlideShare 的信件,提到了 Scribd 接手的事情:「Digital library leader Scribd has acquired SlideShare」,另外 Scribd 這邊也有新聞稿:「Welcome SlideShare to the Scribd community」。
信裡面提到會在九月 24 日生效:
Scribd will begin operating the SlideShare business on September 24, 2020.
另外在 TechCrunch 這邊也有報導「Scribd acquires presentation-sharing service SlideShare from LinkedIn」,看起來目前還沒有小道消息知道轉手的價錢:
SlideShare has a new owner, with LinkedIn selling the presentation-sharing service to Scribd for an undisclosed price.
前幾天在虛擬機內的 Windows 突然被裝了新版的 Edge,發現國外也有報導出來了:「With Edge, Microsoft’s forced Windows updates just sank to a new low」。
這次是 Windows Update 推進來的,即使在 Windows 7 上已經 EoL (2020/01/14),不會有任何安全性更新,微軟也是濫用透過這個方式推進來:
If windows 7 isn't supported then why did my Work machine automatically install Microsoft EDGE last night :|
— DJ_Uchuu - Silicon Dreams Comin' 3rd July ?? (@DjUchuu) June 30, 2020
這種方式也都讓大家想到與 antitrust 的關係:
It all immediately made me think: what would the antitrust enforcers of the ‘90s, who punished Microsoft for bundling Internet Explorer with Windows, think about this modern abuse of Microsoft’s platform?
到底會不會觸發呢...
記者會上有提到現在疾管署的網站上有公開每日送檢數的資料,花了些時間找,在「台灣COVID-19冠狀病毒檢測每日送驗數」這邊可以看到,網站提供的 preview 的界面沒辦法看到最新的資料,但下載後可以看到檔案格式是 UTF-8 的 CSV 檔,應該還算能處理...
找到這個資料花了一些功夫 (因為用 DuckDuckGo 與 Google 都沒直接找到),後來是靠這樣的步驟找到的:
本來點選熱門資料那邊的「COVID-19台灣最新病例、檢驗統計」結果發現只有一筆資料,而且看起來最後更新時間是 2020/04/24,所以得往其他地方翻。
首先點了上面的「最新消息」發現是個系統公告區,不是我要的,接下來才又找到正確的路線...
這時候就會看到最前面提到的「台灣COVID-19冠狀病毒檢測每日送驗數」了。
然後 data.cdc.gov.tw 這個網站看起來是放在 Microsoft Azure 的日本區?
微軟用 MIT License 放出 1983 年版的 GW-BASIC:「Microsoft Open-Sources GW-BASIC」。
這次放出來程式看起來是 x86 assembly,不過放出來的版本好像也不能算是「原始」的版本,而是從 "master implementation" 轉譯出來的版本:
This source was ‘translated’?
Each of the assembly source files contains a header stating This translation created 10-Feb-83 by Version 4.3
Since the Instruction Set Architecture (ISA) of the early processors used in home and personal computers weren’t spectacularly different from one another, Microsoft was able to generate a substantial amount of the code for a port from the sources of a master implementation. (Alas, sorry, we’re unable to open-source the ISA translator.)
主要還是 PR,然後帶一些考古價值...
Notion 把本來收費 USD$4/month 的個人版拆開多推出一個層級,改成 Personal 與 Personal Pro,其中 Personal 包括了:
Unlimited pages & blocks
Share with 5 guests
Sync across devices
而 Personal Pro 則是多了:
Everything in Personal, plus
Unlimited file uploads
Unlimited guests
Version history
API access COMING SOON
不知道這個免費策略跟「Announcing Microsoft Lists - Your smart information tracking app in Microsoft 365」有沒有關係,以拆分 Personal 帳號來說,應該是事前就有先規劃了... 當然也有可能是內部先拿到消息?
Notion 對一般個人要丟東西應該還不錯,現在 Personal 版本少了之前免費版的 1000 blocks 限制,對於 issue tracking 這種會長期一直增加使用量的應用來說應該會方便不少,不過我自己 Trac + MediaWiki 用習慣了,再加上考慮到資料的自主性,應該就不會考慮跳到 Notion 上...
另外之前有抱怨過多帳號登入的部份看起來還是沒解,目前看到的解法還是使用不同的瀏覽器登入管理 (甚至是建議直接用不同的裝置登入),再來就是 Firefox 提供的 container 處理,其實都是在 client 端拆 cookie 的方案,這對於同時有公司帳號與個人帳號的人會變得頗麻煩的...
昨天看到這個有趣的討論,要怎麼樣在一個 API call 裡面花最多錢:「How to burn the most money with a single click in Azure」。
主要是這篇開始,在 AWS 上面買 RDS 的 RI,這一個 API call 可以花三百多萬美金:
Since someone asked today:
An all-upfront reserved instance for a db.r5.24xlarge Enterprise Multi-AZ Microsoft SQL server in Bahrain is $3,118,367.
I challenge you to find a more expensive single @awscloud API call.
— Corey Quinn (@QuinnyPig) March 26, 2020
然後作者試著在 Azure 上找到 Cosmos DB 可以花到九百多萬美金:
另外一個是用 Blob Storage 撐量出來,一億六千多萬美金:
然後最終極的方法是 999 台 instance 的 RI,可以到八億 XDDD:
不過後面這些方法應該買不下去,雲端服務預留的 capacity 應該不夠這樣搞...