Home » Posts tagged "certificate" (Page 3)

Savitech (盛微) 的 USB 音效驅動程式會安裝 Root CA (被發了 CVE-2017-9758)

Hacker News 上看到 CERT 的「Savitech USB audio drivers install a new root CA certificate」提到 Savitech USB audio driver 會安裝自己的 Root CA:

Savitech provides USB audio drivers for a number of specialized audio products. Some versions of the Savitech driver package silently install a root CA certificate into the Windows trusted root certificate store.

出自「Inaudible Subversion - Did your Hi-Fi just subvert your PC? (原網站已經無法訪問,參考備份連結 https://archive.is/K6REr)」,CVE 編號是 CVE-2017-9758,最初是由 n3kt0n 提出的:「某單位 drivers silently install certificate in trusted root certificate authorities store [CVE-2017-9758]」:

Mitre assigned this exposure the identifier CVE-2017-9758, but was initially tracked by HITCON ZeroDay project as ZD-2017-00386.

有兩把 CA public key 被塞進去。雖然目前還沒有徵兆 private key 有外洩,但還是建議儘快移除:

There is currently no evidence that the Savitech private key is compromised. However, users are encouraged to remove the certificate out of caution. The two known certificates are:

SaviAudio root certificate #1
‎Validity: Thursday, ‎May ‎31, ‎2012 - ‎Tuesday, ‎December ‎30, ‎2036
Serial number: 579885da6f791eb24de819bb2c0eeff0
Thumbprint: cb34ebad73791c1399cb62bda51c91072ac5b050

SaviAudio root certificate #2
Validity: ‎Thursday, ‎December ‎31, ‎2015 - ‎Tuesday, ‎December ‎30, ‎2036
Serial number: ‎972ed9bce72451bb4bd78bfc0d8b343c
Thumbprint: 23e50cd42214d6252d65052c2a1a591173daace5

另外 Savitech 也放出了新版的 driver,不包含 Root CA:

Savitech has released a new driver package to address the issue. Savitech drivers version 2.8.0.3 or later do not install the root CA certificate. Users still must remove any previously installed certificate manually.

看了一下說明,看起來是當時為了支援 Windows XP 而做的,但微軟已經不提供驅動程式的數位簽章了,所以就只好這樣搞...

CloudFlare 也要提供 Certificate Transparency 的 Log 伺服器了...

看到 CloudFlare 請求加入 Chromium (Google Chrome) 的伺服器列表:「Certificate Transparency - Cloudflare "nimbus2017" Log Server Inclusion Request」。

對照之前的「Chromium 內提案移除 HPKP (HTTP Public Key Pinning)」以及「Let's Encrypt 的 Embed SCT 支援」,這樣看起來是瀏覽器內會有一份白名單,只有在這白名單上的 Embed SCT 才會被信任...

但弄到這樣的話,log server 是不是也要有稽核機制?

好像哪邊搞錯了方向啊...

Let's Encrypt 的 Embed SCT 支援

翻到 Let's EncryptUpcoming Features 時看到:

Embed SCT receipts in certificates
ETA: February, 2018

對 Embed SCT 不熟,所以查了查這個功能。

這指的是在簽發 SSL certficiate 後,把資料丟給 Certificate Transparency (CT) 伺服器後,伺服器會提供 signed certificate timestamp (SCT);而這個資料放到 SSL certificate 內叫做 Embed SCT:(出自 CT 的 FAQ)

What is an SCT?
An SCT is a signed certificate timestamp. When a certificate authority or a server operator submits a certificate to a log, the log responds with an SCT. An SCT is essentially a promise that the log server will add the certificate to the log in a specific time. The time, known as the maximum merge delay (MMD), helps ensure that certificates are added to logs in a reasonable time. The SCT accompanies the certificate until the certificate is revoked. A TLS server must present the SCT to a TLS client (along with the SSL certificate) during the TLS handshake.

當使用 ECC 時會小於 100 bytes:

How big is an SCT?
SCTs are less than 100 bytes, assuming elliptic curve signatures are used.

這樣才能試著解釋前幾天提到要拔掉 HPKP 的事情:「Chromium 內提案移除 HPKP (HTTP Public Key Pinning)」,也就是為什麼他們是提 CT 解,而不是 DNS CAA 解...

不過我記得 CT server 可以自己架自己 submit 不是嗎?後來有另外規定一定要用第三方的嗎?這樣又很怪...

Chromium 內提案移除 HPKP (HTTP Public Key Pinning)

Twitter 上看到這則 tweet,提到要移除 HPKP (HTTP Public Key Pinning):

blink-dev 上的討論可以參考「Intent To Deprecate And Remove: Public Key Pinning」(就是上面那個連結,只是拉出來)。

這個提案大概可以推敲出理由... 目前的作法必須寫進瀏覽器內,這樣明顯會有 scale 問題,而且這個作法本身就很 workaround,只能保護所謂「高價值」的 domain,而且因為是綁在 Public Key 上,如果 CA 換了 Intermediate Certificate 就有可能會導致檢查過不了。

另外一方面,scale 而且合理的替代方案已經發展出來了。如果瀏覽器會檢查 DNS CAA 資訊 (這個規格可以在 DNS 裡設定有哪些 CA 可以簽這個 domain),就能解這個問題 (加上 DNSSEC 會更加確保驗證過程)。像是這樣:

example.com.    IN      CAA     0 issue "letsencrypt.org"
example.com.    IN      CAA     0 issuewild ";"

不過這個提案本身提到 CT (Certificate Transparency) 怪怪的,因為 CT 無法避免惡意的簽發 (發了以後故意不送 CT):

Finally, remove support for built-in PKP (“static pins”) at a point in the future when Chrome requires Certificate Transparency for all publicly-trusted certificates (not just newly-issued publicly-trusted certificates). (We don’t yet know when this will be.)

但在瀏覽器支援 DNS CAA 可以避免,結果在討論時都沒到 DNS CAA...

另外在 Hacker News 上也有討論:「Public Key Pinning Being Removed from Chrome (groups.google.com)」可以看一下,有個人有提到用 DNS CAA 的方法...

不過印象中這群人對 DNS-based 的方案都不太喜歡,所以也有可能是這樣不考慮在瀏覽器端實作 DNS CAA 吧...

ALB 支援 SNI

AWS 宣佈 ALB 支援 SNI 了:「Application Load Balancers Now Support Multiple TLS Certificates With Smart Selection Using SNI」。

不過這篇比較有趣的是,他範例用的是 VimIsBetterThanEmacs.comVimIsTheBest.com 這兩個網域名稱 XDDD:

I’ll use a few example websites like VimIsBetterThanEmacs.com and VimIsTheBest.com. I’ve purchased and hosted these domains on Amazon Route 53, and provisioned two separate certificates for them in AWS Certificate Manager (ACM). If I want to securely serve both of these sites through a single ALB, I can quickly add both certificates in the console.

波蘭政府的官方網站將會使用 Let's Encrypt

Twitter 上看到這則 tweet,指出波蘭政府的官方網站使用了 Let's Encrypt 的憑證:

SSL Labs 上也可以看出來:「SSL Server Test: www.gov.pl (Powered by Qualys SSL Labs)」。

不過不確定目前是暫時性的 (之後會換成其他的 SSL certificate),還是本來就打算這樣設計了。

Google Chrome 將 .dev 設為 HSTS Preload 名單

其實是兩件事情... 第一件是 Google Chrome.dev 結尾的網域設為 HSTS Preload 名單:「Chrome to force .dev domains to HTTPS via preloaded HSTS」。

第二件事情是隨著第一件來的,HSTS Preload 必須由 domain 擁有人提出啊... 所以 .dev 是合法的 TLD (gTLD)?

文章作者給了答案,是的,而且就是 Google 擁有的:

Wait, there's a legit .dev gTLD?
Yes, unfortunately.

(翻白眼)

這對開發者來說有種無奈感...

不過你可以用這招避開:「在 Google Chrome 連上因 HSTS 而無法連線的網站」,也就是輸入 badidea

另外測試了一下,應該是所有的 A record 都會指到 127.0.53.53,如果有人懶得設定的話也可以用這個位置啦...

Google Chrome 對 Symantec 全系列憑證的不信任計畫

Google Chrome 前陣子整理了一份對 Symantec 憑證的不信任計畫:「Chrome’s Plan to Distrust Symantec Certificates」。

這包括了一卡車的品牌,像是 ThawteVeriSignGeoTrustRapidSSL,不過 Equifax 跟 Symantec 的關係我沒查到...:

Symantec’s PKI business, which operates a series of Certificate Authorities under various brand names, including Thawte, VeriSign, Equifax, GeoTrust, and RapidSSL, had issued numerous certificates that did not comply with the industry-developed CA/Browser Forum Baseline Requirements.

反正整個計畫會在 Google Chrome 70 推出時告一段落 (變成完全不信任),會是 2018/09/13 (預定時間) 與 2018/10/23 (預定時間) 在 beta channel 與 stable channel 上推出。

中間比較重要的時間點是 2018/03/15 (預定時間) 與 2018/04/17 (預定時間),Google Chrome 66 在 beta channel 與 stable channel 上推出,這個版本不會信任 2016/06/01 前發出的憑證:

Chrome 66 released to beta, which will remove trust in Symantec-issued certificates with a not-before date prior to June 1, 2016. As of this date Site Operators must be using either a Symantec-issued TLS server certificate issued on or after June 1, 2016 or a currently valid certificate issued from any other trusted CA as of Chrome 66.
Site Operators that obtained a certificate from Symantec’s old infrastructure after June 1, 2016 are unaffected by Chrome 66 but will need to obtain a new certificate by the Chrome 70 dates described below.

整個計畫的時間軸清楚多了...

Amazon Route 53 支援 CAA record 了

Amazon Route 53 宣佈支援 CAA record 了:「Announcement: Announcement: Amazon Route 53 now supports CAA records」、「Amazon Route 53 now supports CAA records」。

這是一個被動性的 workaround,要求 CA 本身要支援 DNS CAA,所以他沒辦法防止 CA 本身作惡誤簽,但因為負作用與技術債的可能性不高,在 CA/Browser Forum 上被通過強制要求支援了。(參考「未來 CA 將會強制要求檢查 DNS CAA record」)

Gandi 的 DNS 服務也支援了 (要透過 export mode,參考「How can I add a CAA record?」),不過 Linode 還沒做...

Amazon Route 53 將會加緊支援 DNS CAA

看到 Amazon Route 53 要支援 DNS CAA 的消息:「Announcement: Announcement: CAA Record Support Coming Soon」。

裡面有提到 CA/Browser Forum 的決議,要求各瀏覽器支援 DNS CAA:

On March 8, 2017, the Certification Authority and Browser Forum (CA/Browser Forum) mandated that by September 8, 2017, CA’s are expected to check for the presence of a CAA DNS record and, if present, refuse issuance of certificates unless they find themselves on the whitelist <https://cabforum.org/2017/03/08/ballot-187-make-caa-checking-mandatory/>.

DNS CAA 可以設定哪些 SSL certificate 可以發出你的證書,除了自己以外,也可以讓第三者比較容易確認是否有誤發的行為:

We have seen a lot of interest in Amazon Route 53 support for Certification Authority Authorization (CAA) records, which let you control which certificate authorities (CA) can issue certificates for your domain name.

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