Tag Archives: ssh

OpenSSH 完全移除 SSHv1 的程式碼

在「OpenSSH Removes SSHv1 Support」這邊看到 OpenSSH 拔掉 SSHv1 程式碼的消息。 In a series of commits starting here and ending with this one, Damien Miller completed the removal of all support for the now-historic SSHv1 protocol from OpenSSH. 在新的 distribution 裡引入新版 OpenSSH 時就不會有 … Continue reading

Posted in Computer, Murmuring, Network, Security, Software | Tagged , , , , , | Leave a comment

SSH 在 Port 22 的故事

雖然現在全世界都在用 OpenSSH,但當初 SSH 其實是 SSH Communications Security 所發展出來的。最近上面在講當初申請 port 22 的故事:「How SSH Port Became 22」。 選 port 22 是因為剛好要取代 port 21 的 ftp 與 port 23 的 telnet: Anyway, I designed SSH to replace both telnet (port 23) and ftp … Continue reading

Posted in Computer, Murmuring, Network, Security, Software | Tagged , , , , , | Leave a comment

GitHub 決定在 2018/02/01 停用不安全的 HTTPS/SSH 演算法

在「Discontinue support for weak cryptographic standards」這邊訂了日期,2018/02/01 將會關閉: HTTPS 的 TLSv1 與 TLSv1.1 SSH 的 diffie-hellman-group1-sha1 SSH 的 diffie-hellman-group14-sha1 看起來最苦的應該是 Android 4.3 以及更早的版本,以現在的官方數字來看還有 13%+ (Dashboards),這些版本內建的瀏覽器不支援 TLSv1.2,不過另外裝 browser 就還能過...

Posted in Computer, Murmuring, Network, Programming, Security, WWW | Tagged , , , , , , , , , | Leave a comment

每三十秒換一次 ssh port 的 TOTP SSH port fluxing

Facebook 的牆上看到「TOTP SSH port fluxing」這個,有種「沃槽」的感覺... 這方法有種掩耳盜鈴的感覺... (SYN scan 很快的啊)

Posted in Computer, Murmuring, Network, Security, Software | Tagged , , , , , | Leave a comment

用 mRemoteNG 取代 PuTTY

由於架構的隔離政策,有些服務需要透過 VM 裡面的 Windows 存取,所以又花了點時間看看 PuTTY 到底有沒有改善下載問題,也就是 2014 年「Downloading Software Safely Is Nearly Impossible」這邊作者提到的問題 (之前在「如何安全下載軟體...」這篇有提過)。 而即時再過了兩年半,還是沒辦法確認你抓到的 PuTTY 是正確的,Let's Encrypt 還是沒上... 找了一些替代方案,看到 mRemoteNG 這個可以連多種不同 Protocol 的專案,應該會是解法,裝起來用了一陣子感覺還算 okay,之後應該會拿這個用:「mRemoteNG is the next generation of mRemote, open source, tabbed, multi-protocol, remote connections manager.」。 話說回來,找資料的時候發現「simon-git: … Continue reading

Posted in Computer, Murmuring, Network, Security, Software, WWW | Tagged , , , , , , , , , , , , | 2 Comments

OpenSSL 的 DSA 被 Side-channel attack 打爆

在「Make Sure DSA Signing Exponentiations Really are Constant-Time」這篇文章裡面,直接透過 end-to-end 的 timing attack 打爆 (也就是透過 internet 觀察攻擊),而不需要在同一台機器上對 cache 之類的區域攻擊: A unique feature of our work is that we target common cryptographic protocols. Previous works that demonstrate cache-timing key-recovery attack only target … Continue reading

Posted in Computer, Murmuring, Network, Security, Software | Tagged , , , , , , , , , , , , , | Leave a comment

關於 Juniper ScreenOS 防火牆被放後門的研究

一樣是從 Bruce Schneier 那邊看到的:「Details about Juniper's Firewall Backdoor」,原始的研究連結在「Cryptology ePrint Archive: Report 2016/376」這邊。 ScreenOS 被放了兩個後門,一個是 SSH 的後門: Reverse engineering of ScreenOS binaries revealed that the first of these vulnerabilities was a conventional back door in the SSH password checker. 另外一個是「Dual EC … Continue reading

Posted in Computer, Hardware, Murmuring, Network, OS, Security, Software, VPN | Tagged , , , , , , , , , , , | 1 Comment

CVE-2015-7547:getaddrinfo() 的 RCE (Remote Code Execution) 慘案

Google 寫了一篇關於 CVE-2015-7547 的安全性問題:「CVE-2015-7547: glibc getaddrinfo stack-based buffer overflow」。 Google 的工程師在找 OpenSSH 連到某台特定主機就會 segfault 的通靈過程中,發現問題不在 OpenSSH,而是在更底層的 glibc 導致 segfault: Recently a Google engineer noticed that their SSH client segfaulted every time they tried to connect to a specific host. That … Continue reading

Posted in Computer, DNS, Linux, Murmuring, Network, OS, Security, Software | Tagged , , , , , , , , , , , , , , , , , , , , | Leave a comment

OpenSSH client 的重大安全性更新

CVE-2016-0777 與 CVE-2016-0778 安全性漏洞是關於 OpenSSH client 的部分:(USN-2869-1: OpenSSH vulnerabilities) It was discovered that the OpenSSH client experimental support for resuming connections contained multiple security issues. A malicious server could use this issue to leak client memory to the server, including … Continue reading

Posted in Computer, Murmuring, Network, Security, Software | Tagged , , , , , , , | 1 Comment

在攻擊時總是挑最弱的一環:NSA 對 DH 的攻擊

在「How is NSA breaking so much crypto?」這邊提到了 2012 年有文章說明 NSA 有能力解開部份的加密通訊,而後來 Snowden 所提供的資料也證實了這點: In 2012, James Bamford published an article quoting anonymous former NSA officials stating that the agency had achieved a “computing breakthrough” that gave them “the ability to … Continue reading

Posted in Computer, Murmuring, Network, Security, VPN, WWW | Tagged , , , , , , , , , , , , | Leave a comment