Show Notes: linuxactionnews.com/216

The post Linux Action News 216 first appeared on Jupiter Broadcasting.

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“Stack Clash” poses threat to Linux, FreeBSD, OpenBSD, and other OSes

• affects Linux, OpenBSD, NetBSD, FreeBSD and Solaris, on i386 and amd64

• The original blog post

• The official advisory

• The following is not a complete list of CVEs found during the research

• The primary CVE

• Some are secondary and directly related CVE

• Some are independently exploitable and related to sudo

The RNC Files: Inside the Largest US Voter Data Leak

• misconfigured database containing the sensitive personal details of over 198 million American voters was left exposed to the internet by a firm working on behalf of the Republican National Committee (RNC)

• names, dates of birth, home addresses, phone numbers, and voter registration details, as well as data described as “modeled” voter ethnicities and religions.

• exposing the personal information of over sixty-one percent of the entire US population

Dan’s DNS setup

• DNS can be thought of as a phone book
• Once ran a single DNS server at home
• Had both internal (non public) and public hosts in the same zone file
• Moved internal hosts to .int subdomain
• had master/slave in public, but went to svn later
• Held zone files in svn, published them directly to servers

Feedback

• Freenas – Transferring files locally see sysutils/fusefs-ntfs

• Password managers filling in credentials

• Episode 323 Yellow dots give you see also https://en.wikipedia.org/wiki/EURion_constellation

• You cannot turn off Windows 10 Telemetry with a Group Policy

Round Up:

• WannaCry computer worm to North
  Korea

• Rooting a Printer

• Travel (Linux) laptop setup

• FreeNAS 11.0 is Now Here

The post DNS Mastery | TechSNAP 324 first appeared on Jupiter Broadcasting.

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Unix Trifecta — Patch Your Shit

• This week saw the trifecta, critical vulnerabilities in 3 of the most important and widely used server applications
• CVE-2016-8610 – OpenSSL: A remote attacker who can initiate handshakes with an OpenSSL based server can cause the server to consume a lot of computation power with very little bandwidth usage, and may be able to use this technique in a leveraged Denial of Service attack.
• The flaw is in the way OpenSSL handles “SSL Alerts”. The SSL alert protocol is a way to communicate problems within a SSL/TLS session. Due to improper handling of alert packets, OpenSSL would consume an excessive amount of CPU time processing undefined alert messages.
  • CVE-2016-8864 – Bind: A remote attacker who could cause a server to make a query deliberately chosen to trigger the failed assertions could cause named(8) to stop, resulting in a Denial of Service condition to its clients.
  • A defect in BIND’s handling of responses containing a DNAME answer could cause a resolver to exit after encountering an assertion failure in db.c or resolver.c.
  • CVE-2016-8858 – OpenSSH: A remote attacker may be able to cause a SSH server to allocate an excessive amount of memory. Note that the default MaxStartups setting on FreeBSD will limit the effectiveness of this attack.
• During the SSH handshake procedure, the client and server exchanges the supported encryption, MAC and compression algorithms along with other information to negotiate algorithms for initial key exchange, with a message named SSH_MSG_KEXINIT.
• When processing the SSH_MSG_KEXINIT message, the server could allocate up to a few hundreds of megabytes of memory per each connection, before any authentication take place.
• Patches for most OSes should be out by now, make sure you install them.

LessPass, an open source, storage-less password manager? Or is it…

• “Managing your Internet passwords is not easy. You probably use a password manager to help you. The system is simple, the tool generates random passwords whenever you need them and save them into a file protected with a strong password. This system is very robust, you only need to remember one password to rule them all! Now you have a unique password for each site on the Internet.”
• But, there are some shortcomings to that type of password manager
• How do I synchronize this file on all my devices?
• How do I access a password on my parents’ computer without installing my password manager?
• How do I access a password on my phone, without any installed app?
• To solve this, LessPass does it differently
• “The system uses a pure function, i.e. a function that given the same parameters will always give the same result. In our case, given a login, a master password, a site and options it will returns a unique password”
• “No need to save your passwords in an encrypted file. You just need to access the tool to recalculate a password from information that you know (mostly the login)”
• There are some issues though.
  • Some sites have different password complexity requirements, such as banks that limit the length of your password, or require a PIN that is all digits
  • Some sites obviously do not hash passwords correctly, and do not allow some characters
  • What if you want to, or need to, change your password?
• LessPass has a solution for all of these, where you specify “password profile”, to remember the different complexity settings to generate the valid password
• To manage to change the password, there is also a counter, that starts at 1, and you increment to get a different password.
• Of course now, you have to remember: your login, your master password, the password complexity profile for each site, and how many times you have changed your password on that site
• So, they have a “connected” version, that remembers each site, your login, the password profile, and your password change counter.
• There are obviously some privacy concerns, and security concerns here.
• How do you restrict access in the connected version, with a username and password? Is that password the same or different from your master password. Is your profile data encrypted per user?
• Of course, being an open source project, there is the option to self-host, which eliminates a number of those concerns
• “You can host your own LessPass database if you do not want to use the official one. The requirement for self-hosting is to have docker and docker-compose installed on your machine.”
• The fact that the installation instructions are curl | bash (written the other way around, so that when you stick sudo in front of it it works), does raise some other concerns
• This leaves a few problems:
  • You can never change your master password, as it will effectively change all of your passwords
  • It is still technically possible for someone to brute force your master password. Each attempt will require them to do the full PBKDF2 run, but 8192 rounds will take only a small fraction of a second, and it can be parallelized quite well. If someone does compromise your master password (via brute force, or with a keylogger, or whatever), they have access to all of your passwords, but worse, they even have access to your ‘new’ passwords, if you change your password, it just changes the ‘count’ parameter, so I could generate your next 10 gmail passwords and keep them for later.
  • The key-derivation seems weak, 8192 rounds of PBKDF2 is likely not enough. LastPass uses 100,000 rounds for its server-side key-derivation. FreeBSD’s GELI disk encryption uses a number of rounds that will take approximately 2 seconds, which on modern machines is over 1 million rounds. The issue is that changing this number in the future will change all of your passwords. At a minimum, it should be part of the password profile, so you can select a different value for each site, so you can change the default for new sites in the future, and increase the strength of the password for one site by changing the password.
  • LessPass cannot deal with SSO (Single Sign On). There are a number of sites for which I have the same password, because they all authenticate against the same LDAP database (or ActiveDirectory). LessPass ONLY allows you to use its derived passwords, which might not always work.
• There are definitely some interesting aspects to LessPass, especially being able to self host, but, I don’t think I’ll be switching to it.

A very valuable vulnerability

• It all started with a facebook post by Colin Percival: “I think I just accidentally exploited a “receive arbitrarily large amounts of money” security vulnerability. Oops.”
• Colin Percival is a security and cryptography expert, and a former FreeBSD Security Officer
• Colin’s day job is running Tarsnap – backups for the truly paranoid.
• To accept payments for his business, he uses Stripe – a credit card processing service, which also allows him to accept bitcoins
• “While I very firmly wear a white hat, it is useful to be able to consider things from the perspective of the bad guys, in order to assess the likelihood of a vulnerability being exploited and its potential impact. For the subset of bad guys who exploit security vulnerabilities for profit — as opposed to selling them to spy agencies, for example — I imagine that there are some criteria which would tend to make a vulnerability more valuable:”
  • the vulnerability can be exploited remotely, over the internet;
• the attack cannot be blocked by firewalls;
  • the attack can be carried out without any account credentials on the system being attacked;
  • the attack yields money (as opposed to say, credit card details which need to be separately monetized);
  • once successfully exploited, there is no way for a victim to reverse or mitigate the damage; and
  • the attack can be performed without writing a single line of code.
• “Much to my surprise, a few weeks ago I stumbled across a vulnerability satisfying every one of these criteria.”
• “The vulnerability — which has since been fixed, or else I would not be writing about it publicly — was in Stripe’s bitcoin payment functionality. Some background for readers not familiar with this: Stripe provides payment processing services, originally for credit cards but now also supporting ACH, Apple Pay, Alipay, and Bitcoin, and was designed to be the payment platform which developers would want to use; in very much the way that Amazon fixed the computing infrastructure problem with S3 and EC2 by presenting storage and compute functionality via simple APIs, Stripe fixed the “getting money from customers online” problem. I use Stripe at my startup, Tarsnap, and was in fact the first user of Stripe’s support for Bitcoin payments: Tarsnap has an unusually geeky and privacy-conscious user base, so this functionality was quite popular among Tarsnap users.”
• “Despite being eager to accept Bitcoin payments, I don’t want to actually handle bitcoins; Tarsnap’s services are priced in US dollars, and that’s what I ultimately want to receive. Stripe abstracts this away for me: I tell Stripe that I want $X, and it tells me how many bitcoins my customer should send and to what address; when the bitcoin turns up, I get the US dollars I asked for. Naturally, since the exchange rate between dollars and bitcoins fluctuates, Stripe can’t guarantee the exchange rate forever; instead, they guarantee the rate for 10 minutes (presumably they figured out that the exchange rate volatility is low enough that they won’t lose much money over the course of 10 minutes). If the “bitcoin receiver” isn’t filled within 10 minutes, incoming coins are converted at the current exchange rate.”
• “For a variety of reasons, it is sometimes necessary to refund bitcoin transactions: For example, a customer cancelling their order; accidentally sending in the wrong number of bitcoins; or even sending in the correct number of bitcoins, but not within the requisite time window, resulting in their value being lower than necessary. Consequently, Stripe allows for bitcoin transactions to be refunded — with the caveat that, for obvious reasons, Stripe refunds the same value of bitcoins, not the same number of bitcoins. (This is analogous to currency exchange issues with credit cards — if you use a Canadian dollar credit card to buy something in US dollars and then get a refund later, the equal USD amount will typically not translate to an equal number of CAD refunded to your credit card.)”
• The vulnerability lay in the exchange rate handling. As I mentioned above, Stripe guarantees an exchange rate for 10 minutes; if the requisite number of bitcoins arrive within that window, the exchange rate is locked in. So far so good; but what Stripe did not intend was that the exchange rate was locked in permanently — and applied to any future bitcoins sent to the same address. This made a very simple attack possible:
  • Pay for something using bitcoin.
  • Wait until the price of bitcoin drops.
  • Send more bitcoins to the address used for the initial payment.
  • Ask for a refund of the excess bitcoin.
• “Because the exchange rate used in step 3 was the one fixed at step 1, this allowed for bitcoins to be multiplied by the difference in exchange rates; if step 1 took place on July 2nd and steps 3/4 on August 2nd, for example, an arbitrary number of bitcoins could be increased by 30% in a matter of minutes. Moreover, the attacker does not need an account with Stripe; they merely need to find a merchant which uses Stripe for bitcoin payments and is willing to click “refund payment” (or even better, is set up to automatically refund bitcoin overpayments).”
• “Needless to say, I reported this to Stripe immediately. Fortunately, their website includes a GPG key and advertises a vulnerability disclosure reward (aka. bug bounty) program; these are two things I recommend that every company does, because they advertise that you take security seriously and help to ensure that when people stumble across vulnerabilities they’ll let you know. (As it happens, I had Stripe security’s public GPG key already and like them enough that I would have taken the time to report this even without a bounty; but it’s important to maximize the odds of receiving vulnerability reports.) Since it was late on a Friday afternoon and I was concerned about how easily this could be exploited, I also hopped onto Stripe’s IRC channel to ask one of the Stripe employees there to relay a message to their security team: “Check your email before you go home!””
• “Stripe’s handling of this issue was exemplary. They responded promptly to confirm that they had received my report and reproduced the issue locally; and a few days later followed up to let me know that they had tracked down the code responsible for this misbehaviour and that it had been fixed. They also awarded me a bug bounty — one significantly in excess of the $500 they advertise, too.”
• “As I remarked six years ago, Isaac Asimov’s remark that in science “Eureka!” is less exciting than “That’s funny…” applies equally to security vulnerabilities. I didn’t notice this issue because I was looking for ways to exploit bitcoin exchange rates; I noticed it because a Tarsnap customer accidentally sent bitcoins to an old address and the number of coins he got back when I clicked “refund” was significantly less than what he had sent in. (Stripe has corrected this “anti-exploitation” of the vulnerability.) It’s important to keep your eyes open; and it’s important to encourage your customers to keep their eyes open, which is the largest advantage of bug bounty programs — and why Tarsnap’s bug bounty program offers rewards for all bugs, not just those which turn out to be vulnerabilities.”
• “And if you have code which handles fluctuating exchange rates… now might be a good time to double-check that you’re always using the right exchange rates.”
• A very interesting attack, that was only found because someone accidentally did the wrong thing

Feedback:

• ipV6 vs Mirai

• Freenas replication

• Freenas 10 question

• Backup & LUKS

• Chromecast across subnets

• A user wrote in about the mention of BCP38 the other week, and asked what other best practises there are: here is a list

Round Up:

• Windows Atom Tables popped by security researchers
• The Million-Key Question—Investigating the Origins of RSA Public Keys
• Microsoft stops selling Windows 7 and Windows 8.1 to computer makers i
• Researchers make high performance battery from junkyard scraps
• Why Windows hack is being blamed on Russia-linked group
• “Decimeter-Level Localization with a Single WiFi Access Point” — Locating a device to within 4 inches using only 1 WiFi access point
• Stealth Cell Tower
• Kaspersky quarterly DDoS report: 70-80% of botnets consist of Linux devices, most attacks last under 4 hours.
• Level 3 drops its packets for hours, causing Internet traffic jam
• Microsoft Reimagines Open Source Cloud Hardware
• Pagliano Emails Detail Attempts to Hack Clinton Unsecure Email Server 10 Times in Two Days in November 2010 – U.S. Secret Service Informed of Hacking Attempts – Judicial Watch
• Teenager accidentally DDoSes 911 system

The post Unix Security Trifecta | TechSNAP 292 first appeared on Jupiter Broadcasting.

Coming up this week, we’ll be chatting with Shawn Webb about his recent work with ASLR and PIE in FreeBSD.

After that, we’ll be showing you how you can create a reverse SSH tunnel to a system behind a firewall… how sneaky. Answers to your emails plus the latest news, on BSD Now, the place to B.. SD.

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Headlines

FreeBSD foundation August update

• The foundation has published a new PDF detailing some of their recent activities
• It includes project development updates, the 10.1-RELEASE schedule and some of its new features
• There is also a short interview with Dru Lavigne in the “voices from the community” section
• If you’re into hardware, there’s another section about some new FreeBSD server equipment
• In closing, there’s an update on funding too

NSD for an authoritative nameserver

• With BIND having been removed from FreeBSD 10.0, you might be looking to replace your old DNS setup
• This article shows how to use NSD for an authoritative DNS nameserver
• It’s also got a link to a similar article on Unbound, the new favorite recursive and caching resolver (they work great together)
• All the instructions are presented very neatly, with all the little details included
• Less BIND means less vulnerabilities, everybody’s happy

BIND and Nginx removed from OpenBSD

• While we’re on the topic of DNS servers, BIND was finally removed from OpenBSD as well
• The base system contains both NSD and Unbound, so users can transition over between 5.6 (November of this year) and 5.7 (May of next year)
• They’ve also removed nginx from the base system, in favor of the new custom HTTP daemon
• BIND and Nginx are still available in ports if you don’t want to switch
• We’re hoping to have Reyk Floeter on the show next week to talk about it, but scheduling might not work out, so it may be a little later on
• With Apache gone in the upcoming 5.6, It’s also likely that sendmail will be removed before 5.7 – hooray for modern alternatives

NetBSD demo videos

• A Japanese NetBSD developer has been uploading lots of interesting videos
• Unsurprisingly, they’re all featuring NetBSD running on exotic and weird hardware
• Most of them are demoing sound or running a modern Twitter client on an ancient computer
• They’re from the same guy that did the conference wrap-up we mentioned recently

Interview – Shawn Webb – shawn.webb@hardenedbsd.org / @lattera

Address space layout randomization in FreeBSD

Tutorial

Reverse SSH tunneling

News Roundup

Puppet master-agent installation on FreeBSD

• If you’ve got a lot of BSD boxes under your control, or if you’re just lazy, you’ve probably looked into Puppet before
• The author claims a lack of BSD-specific Puppet documentation, so he decided to write up some notes of his own
• He goes through some advantages of using this type of tool for deployments, even when you don’t have a huge number of systems
• The rest of the post explains how to set up both the master and the agent configurations

Misc. pfSense items

• We found a few miscellaneous pfSense articles this past week
• The first one is about the hunt for the “ultimate” free open source firewall, where pfSense is obviously a strong contender
• The second one shows how to log NAT firewall states
• In the third, you can see how to automatically back up your configuration files
• The fourth item shows how to set up PXE booting with pfSense, similar to one of our tutorials

Time Machine backups on ZFS

• If you’ve got a Mac you need to keep backed up, a FreeBSD server with ZFS can take the place of an expensive “time capsule”
• This post walks you through setting up netatalk and mDNS for a very versatile Time Machine backup system
• With a single command on the OS X side, you can write to and read from the BSD box just like a regular external drive
• Surprisingly simple to do, recommended for anyone with Macs on their network

Lumina desktop preview

• Lumina, the BSD-exclusive desktop environment, seems to be coming along nicely
• The main developer has posted an update on the PCBSD blog with some screenshots
• Lots of new features have been added, many of which are documented in the post
• There just might be a BSD Now episode about Lumina coming up.. (cough cough)

Feedback/Questions

• Gary writes in
• Cedric writes in
• Caldwell writes in
• Cary writes in

• All the tutorials are posted in their entirety at bsdnow.tv
• The stunnel tutorial – that’s right, our very first one – got some updates and fixes
• Send all your BSD-related questions, comments, show ideas/topics, or stories you want mentioned on the show to feedback@bsdnow.tv
• We’d really love to feature more articles from the viewers – be it about one of the main BSDs or something like pfSense/FreeNAS – send us anything cool you write (or find)
• Watch live Wednesdays at 2:00PM Eastern (18:00 UTC)
• Next week is something special… we’ll just leave it at that

The post Reverse Takeover | BSD Now 52 first appeared on Jupiter Broadcasting.

After returning from a successful EuroBSDCon in Malta, we\’re back to get you caught up on all the latest news! We\’ve got stories, interviews and a special treat for OpenBSD fans later in the show. All that and more on this week\’s BSD Now, the place to B.. SD.

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Headlines

FreeBSD 9.2 released

• FreeBSD 9.2-RELEASE is finally out
• Highlights include ZFS TRIM and LZ4 support, virtio drivers, dtrace and OpenSSH updates as well as lots of driver improvements
• Will be supported until 2014-09-30
• Get out there and freebsd-update or buildworld!

Four new NetBSD releases

• NetBSD 5.2 and 5.1 branches get security and bugfix updates
• The 6.1 and 6.0 branches were updated soon after, also with security updates and bug fixes
• Check the show notes for the full changelog

BIND being replaced by unbound in FreeBSD

• Most FreeBSD users are familiar with BIND from the security notifications
• It has has many vulnerabilities over the years, and we’ll finally be rid of it
• Being replaced with unbound and ldns, everyone rejoices
• As of September 24th, BIND is no longer built by default
• As of September 30th, BIND was completely removed
• Includes an easy to use script for local DNS
• OpenBSD also has unbound in base, but it\’s not built by default yet

DragonflyBSD future plans

• An announcement was posted that details some possible plans for Dragonfly
• dports (their version of FreeBSD ports) will be switching to GCC 4.7
• i915 support is probably going to be in version 3.6
• Work is being done on HAMMER 2, but it won\’t make it to 3.6
• 3.6 is also likely going to ditch pkgsrc as the default in favor of dports, due to a hugely positive reaction from the community

FreeBSD ports get Stack Protector support

• Some portsnap users noticed a massive sweep of every port being updated
• Shortly after, stack protector support was announced by Bryan Drewery
• Only works on i386 and AMD64 on FreeBSD 10 and AMD64 on 9
• Hopefully will become the default, but needs to go through some testing and exp-runs

EuroBSDCon 2013 wrap-up chat

• BSD Now is back from EuroBSDCon with lots of stories
• We picked up an OpenBSD 5.4 CD set at EuroBSDCon, before the official release
• We\’ll give a little showcase of what\’s inside, they put a lot of effort into it
• Comes with the OS, source code, stickers, music, cool other stuff
• Consider supporting the OpenBSD project

Interview

Kirk McKusick

Tutorial

Faster recompiles with ccache and RAM disks

• Rebuilding ports can be sped up with ccache
• RAM disk eliminates disk I/O bottlenecks
• poudriere uses both of these to speed up binary package builds

News Roundup

List of vBSDCon speakers posted

• Registration will be open until October 23rd
• Presentations covering FreeBSD, OpenBSD, FreeNAS and others

Xen PVHVM added to GENERIC

• It\’s now possible to run FreeBSD 10 under Xen with the GENERIC kernel
• freebsd-update will work now
• With FreeBSD 10 ALPHA 4 just being released, should be interesting
• We should call the new kernel \”XENERIC\”

Dragonfly AMD KMS port

• A Dragonfly user has started porting the new FreeBSD AMD KMS driver
• Still a work in progress, asking for help from the community

NetBSD gets an nVidia driver

• NetBSD gets a preliminary nVidia driver
• So far only supports the GeForce 2MX, so not a lot of use just yet
• No acceleration yet, but it\’s a start

FreeBSD cracks the top 10 on DistroWatch

• Over the last year FreeBSD has steadily moved up the rankings from #18 to #10
• Increasing from an average of 570 to 779 hits per day
• Surpassed CentOS, Puppy Linux and Slackware

Feedback/Questions

• Charlie writes in with a lot of questions: https://slexy.org/view/s21jRKf7lp
• Kjell-Aleksander writes in: https://slexy.org/view/s2M0OKmxMK
• Stefen writes in: https://slexy.org/view/s2YlVuhhUa
• Sichendra writes in: https://slexy.org/view/s2P7KtE5x2

• All the tutorials are posted in their entirety at bsdnow.tv
• Send questions, comments, show ideas/topics, etc to feedback@bsdnow.tv
• We don’t check YouTube comments, JB comments, Reddit, etc. If you want us to see it, send it via email (the preferred way) or Twitter (also acceptable)
• Watch live Wednesdays at 2:00PM Eastern (18:00 UTC)

The post Stacks of Cache | BSD Now 5 first appeared on Jupiter Broadcasting.

Remember the Man in the Middle attack on google from last week? Turns out it was far worse than though, we now have more details on the DigiNotar compromise, and a number of other important sites have had their DNS hijacked.

Plus we cover the advantages of running your own DNS server at home, and how Allan and Chris got their start in the world of IT!

All that and more, in this week’s TechSNAP!

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