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Enabling Dual Factor Authentication on Linux SSH logins..

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Linux

A couple of weeks ago I wrote a post on using a Chromebook to develop on a cloud platform. Its based on a Digital Ocean remote server and like most people who wish to attach to the command line interface on a remote server I use SSH. It’s an encrypted connection over the network/internet from end to end. However being a cloud server I was wondering if it was possible to secure this a little bit more?

A chat with a friend on the way into work provided me with a solution.

The solution is Two Factor authentication a system beased on a simple premise, something you know (the SSH password in this case) and something you have (your mobile phone in this case, but it could be a secure token) which will deliver a random number.

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Security: VPNFilter, Encryption in GNU/Linux, Intel CPU Bug Affecting rr Watchpoints

  • [Crackers] infect 500,000 consumer routers all over the world with malware

    VPNFilter—as the modular, multi-stage malware has been dubbed—works on consumer-grade routers made by Linksys, MikroTik, Netgear, TP-Link, and on network-attached storage devices from QNAP, Cisco researchers said in an advisory. It’s one of the few pieces of Internet-of-things malware that can survive a reboot. Infections in at least 54 countries have been slowly building since at least 2016, and Cisco researchers have been monitoring them for several months. The attacks drastically ramped up during the past three weeks, including two major assaults on devices located in Ukraine. The spike, combined with the advanced capabilities of the malware, prompted Cisco to release Wednesday’s report before the research is completed.

  • Do Not Use sha256crypt / sha512crypt - They're Dangerous

    I'd like to demonstrate why I think using sha256crypt or sha512crypt on current GNU/Linux operating systems is dangerous, and why I think the developers of GLIBC should move to scrypt or Argon2, or at least bcrypt or PBKDF2.

  • Intel CPU Bug Affecting rr Watchpoints
    I investigated an rr bug report and discovered an annoying Intel CPU bug that affects rr replay using data watchpoints. It doesn't seem to be hit very often in practice, which is good because I don't know any way to work around it. It turns out that the bug is probably covered by an existing Intel erratum for Skylake and Kaby Lake (and probably later generations, but I'm not sure), which I even blogged about previously! However, the erratum does not mention watchpoints and the bug I've found definitely depends on data watchpoints being set. I was able to write a stand-alone testcase to characterize the bug. The issue seems to be that if a rep stos (and probably rep movs) instruction writes between 1 and 64 bytes (inclusive), and you have a read or write watchpoint in the range [64, 128) bytes from the start of the writes (i.e., not triggered by the instruction), then one spurious retired conditional branch is (usually) counted. The alignment of the writes does not matter, and it's not related to speculative execution.

In Memoriam: Robin "Roblimo" Miller, a Videographer and Free Software Champion

Videographer Robin Roblimo Miller

Robin "Roblimo" Miller was a clever, friendly, and very amicable individual who everyone I know has plenty of positive things to say about. I had the pleasure of speaking to him for several hours about anything from personal life and professional views. Miller was a very knowledgeable person whose trade as a journalist and video producer I often envied. I have seen him facing his critics in his capacity as a journalist over a decade ago when he arranged a debate about OOXML (on live radio). Miller, to me, will always be remembered as a strong-minded and investigative journalist who "did the right thing" as the cliché goes, irrespective of financial gain -- something which can sometimes be detrimental to one's longterm health. Miller sacrificed many of his later years to a cause worth fighting for. This is what we ought to remember him for. Miller was - and always will be - a FOSS hero.

May everything you fought for be fulfilled, Mr. Miller. I already miss you.

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