A Firsthand Look at Disaster Recovery: Tethering and IAX with Asterisk
One of the exciting challenges of building a swimming pool is knowing that it’s just a matter of time until your Internet connection dies. As you might imagine, swimming pools are major construction and involve a lot of digging. And digging usually means some oops moments when cables get cut. In our case, we had watched the folks digging the trenches for all of the pool plumbing to be sure they didn’t accidentally whack one of three coax cables coming into our house. And, when it came time to cover up the trenches, we pointed out the orange cables to the Bobcat driver knowing we were finally home free. Not so fast! Two minutes later, Mario had driven the Bobcat right over the primary Internet cable leaving the shredded remains sticking up through the dirt. Oops. Sorry. Shit happens!
Looking on the positive side, we chuckled, "What a perfect opportunity to test our backup Asterisk® system!" Our backup system is pretty clever if we do say so. It relies upon a Verizon WiFi HotSpot running on our Galaxy smartphone and a duplicate of our Asterisk-based PBX in a Flash™ server running as a virtual machine under VirtualBox on an iMac desktop. The entire setup takes less than a minute to activate. Well, that was the plan anyway.
It turns out that Verizon does SIP a little differently with a SIP ALG in the path so Asterisk couldn’t register with all but one of our dozen SIP providers. Congratulations, CallCentric! The workaround is to enable STUN. That is now possible with Asterisk 11. Short of that, you’re left with CallCentric. Unfortunately for us, we don’t do much SIP trunking with CallCentric, and none of our primary DIDs are connected through them. The other option is to add port=5080 to your trunk setup with any SIP trunks you register with VoIP.ms using a username and password. Our attention span was too short to tackle STUN in the middle of this crisis. But there’s good news. Verizon doesn’t mess with IAX network traffic at all. Since a couple of our primary DIDs are registered with VoIP.ms using IAX trunks, restoring these IAX trunks to full functionality took less than a minute. That is step one of a three-step process. You need inbound trunks, phones, and outbound trunks to get your redundant VoIP server back in business.
Getting phones to function on what is now a purely WiFi network (through the Verizon HotSpot) can be problematic unless you’ve done your homework and sprinkled a few WiFi-capable SIP phones around your home or office. In our case, we still have Grandstream’s GXP2200 Android phones scattered everywhere so it was just a matter of plugging in the WiFI adapters and rebooting. The newer GXV3240 would work just as well.1
All that remained was enabling several trunks for outbound calls. Since VoIP.ms IAX trunks support both incoming and outgoing calls, we were home free. And, with Google Voice trunks, it was simply a matter of jumping through Google’s security hoops to reenable the connections on a new IP address.
Lessons Learned. Here’s a quick checklist for those of you that think about disaster recovery for your home or for clients and businesses. Nothing beats some advance planning. If money is no object, then WiFi tethering from a smartphone with one of the major providers whose service works well in your home or office environment is the way to go. 4G is a must!
In our case, money was an object so we had the foresight to acquire a Verizon SIM card from eBay that included an unlimited data plan. With this setup, it costs only $1 a day extra to add WiFi tethering, and you can turn it off and on as often as you like without any additional fees or surcharges. There also are no additional charges for using boatloads of data! We’re actually writing this column with a tethered connection from a hotel in Washington (results above). To give you some idea of why an unlimited data plan is important, our home operation burned through 4 gigs of data in less than 24 hours once we activated WiFi tethering. Of course, there were people doing things other than making phones calls, but tethering enables 5 connections to function just about like the cable modem service you originally had in place. So expect the data usage to be substantial. Everybody likes 24/7 Internet service.
Loss of phone calls through a PBX is more of an annoyance than a crisis these days because almost everyone also has a smartphone. Even so, the SIP gotcha with Verizon Wireless was a surprise because we hadn’t really tested our super-duper emergency system in advance. That wasn’t too smart obviously. The old adage applies. Do as we say, not as we do. Unplug your cable modem or DSL connection and actually test your backup system before D-Day arrives.
On the VoIP provider end, now is the time to set up an account with a provider that offers both SIP and IAX connectivity. Step 2 is to actually configure an IAX trunk (as a subaccount to use VoIP.ms parlance) and test it. IAX trunks actually have fewer headaches with NAT, but there are only a handful of providers that still provide the service. Find one now and make certain that your primary DIDs will roll over to the IAX trunk in case of an outage. I’m always reminded that we have Mark Spencer to thank for IAX. It was his brainchild. Thank you, Mark! With VoIP.ms, you also can spoof your CallerID so that calls will still appear to originate from your primary Asterisk PBX.
Keep in mind that a VirtualBox-based Asterisk virtual machine and a Desktop computer both need an IP address and will have to be started on WLAN0 rather than ETH0. Remember, your wired connection is now dead.
You’re also going to want to acquire at least a couple of WiFi-capable SIP phones that can be connected with your Asterisk server using your WiFi HotSpot. Also make certain that you have a preconfigured IPtables firewall on your backup system. Remember, your hardware-based firewall connected to your cable modem won’t provide any protection once you switch to HotSpot operation. Lucky for you, Incredible PBX™ servers come preconfigured with a locked-down IPtables firewall and a WhiteList. Just add the new IP addresses of your server and phones, and you’re secure on the public Internet.
Finally, let’s do the HotSpot connection math. You’ll need an IP address for your desktop computer running VirtualBox. You’ll need a second IP address for the Asterisk virtual machine. Then you’ll need an IP address for every WiFi-enabled SIP phone. If the maximum number of connections is five on your HotSpot, that means you’ve got the necessary capacity for at most 3 WiFi SIP phones assuming you don’t enable a WiFi printer and if nobody else wants to use a computer during the outage. The other option is to add an inexpensive travel router with bridge mode to your mix of 5 devices. We always keep one handy for extended trips. A properly configured travel router provides an additional WiFi network with some extra WiFi connections. Good luck!
Security Alerts. Serious SSL and FreePBX security vulnerabilities have been discovered AND patched during the past week. If you have not patched your server and Asterisk, FreePBX, Apache, and/or WebMin are exposed to the public Internet, you have a serious problem on your hands. See this thread for details on the FreePBX vulnerability. And see this thread for the steps necessary to patch SSL in Asterisk, Apache, and Webmin. While Incredible PBX servers were automatically patched for the FreePBX vulnerability, the SSL issues require manual patching and an Asterisk upgrade. A script for upgrading Asterisk 11 servers is included in the message thread linked above. ALWAYS run your VoIP server behind a firewall with no Internet port exposure to Asterisk, FreePBX, SSH, or the Apache and Webmin web servers! And, if you think all of this security stuff is just a silly waste of your time, then read about the latest lucky recipient of a $166,000 phone bill.
Originally published: Monday, October 20, 2014
Need help with Asterisk? Visit the PBX in a Flash Forum.
Special Thanks to Our Generous Sponsors
FULL DISCLOSURE: ClearlyIP, Skyetel, Vitelity, DigitalOcean, Vultr, VoIP.ms, 3CX, Sangoma, TelecomsXchange and VitalPBX have provided financial support to Nerd Vittles and our open source projects through advertising, referral revenue, and/or merchandise. As an Amazon Associate and Best Buy Affiliate, we also earn from qualifying purchases. We’ve chosen these providers not the other way around. Our decisions are based upon their corporate reputation and the quality of their offerings and pricing. Our recommendations regarding technology are reached without regard to financial compensation except in situations in which comparable products at comparable pricing are available from multiple sources. In this limited case, we support our sponsors because our sponsors support us.
BOGO Bonaza: Enjoy state-of-the-art VoIP service with a $10 credit and half-price SIP service on up to $500 of Skyetel trunking with free number porting when you fund your Skyetel account. No limits on number of simultaneous calls. Quadruple data center redundancy. $25 monthly minimum spend required. Tutorial and sign up details are here.
The lynchpin of Incredible PBX 2020 and beyond is ClearlyIP components which bring management of FreePBX modules and SIP phone integration to a level never before available with any other Asterisk distribution. And now you can configure and reconfigure your new Incredible PBX phones from the convenience of the Incredible PBX GUI.
VitalPBX is perhaps the fastest-growing PBX offering based upon Asterisk with an installed presence in more than 100 countries worldwide. VitalPBX has generously provided a customized White Label version of Incredible PBX tailored for use with all Incredible PBX and VitalPBX custom applications. Follow this link for a free test drive!
Special Thanks to Vitelity. Vitelity is now Voyant Communications and has halted new registrations for the time being. Our special thanks to Vitelity for their unwavering financial support over many years and to the many Nerd Vittles readers who continue to enjoy the benefits of their service offerings. We will keep everyone posted on further developments.
Some Recent Nerd Vittles Articles of Interest…
- Some of our links refer users to Amazon or other service providers when we find their prices are competitive for the recommended products. Nerd Vittles receives a small referral fee from these providers to help cover the costs of our blog. We never recommend particular products solely to generate commissions. However, when pricing is comparable or availability is favorable, we support these providers because they support us. [↩]
The Disappointing iPhone 6: Eight Generations of iOS and Bluetooth Still Sucks
Our technology reviews are a little different than the dozens of reviews you’ve probably already seen that read more like Apple press releases. First of all, we typically buy products to actually use. And second, we base our smartphone evaluations on real-world requirements rather than best case scenarios that you’re unlikely to ever experience in the real world.
So we begin our review of the iPhone 6 with the simple question: "Can it make calls?" Funny as this sounds, it’s been a huge problem with previous iPhone models if you planned to use a reasonably priced provider such as StraightTalk instead of one of America’s "Big Four." To Apple’s credit, they finally got it right in the AT&T model of the iPhone 6. StraightTalk works out of the box, something Android mastered years ago. You still cannot manually configure the cellphone provider specs, but at least it now works.
We’re not going to spend a lot of time on Apple’s continuing push to lock users into the Apple universe. Suffice it to say, the lock in marches on with each new release. To some it’s a good thing. To others, it’s not. If you’re going to fork over $1,0001 for an iPhone 6 in order to use StraightTalk for $45 a month, then you’re probably committed to and comfortable with Apple’s ways of doing things. We’re pretty much an observer of the iPhone cosmos except to assure that our VoIP products still work reliably on the platform. On the other hand, our teenager and all of her teenage friends have iPhones, period. Just the mention of Android conjures up visions of nerds hanging from trees to hear them tell it. In other words, lock in is a good thing in their view. All of their apps work exactly the same on every person’s smartphone. All of their emojis are compatible for texting. And messaging is pure Apple with no worries whether SMS and MMS work or not. By the way, messaging is still a mess if you switch between Apple and Android with your SIM card without first disabling iMessage on the iPhone. It’s almost as if Apple likes it this way. 😉
Did we mention that the iPhone 6 is gorgeous? Hands down, it is the best looking smartphone ever. We won’t get into whether it bends or not. Ours didn’t, and we carry it in our pocket like every other guy on the planet. Not sure I’d do it if I rode on a tractor all day but in typical everyday use, it holds it’s own.
We were especially curious about the camera given the numerous reviews documenting that the iPhone 6 is not the megapixel wonder you’ve come to expect with Android phones. We’ve typically been able to take much better real-world photos using Samsung’s Galaxy S4. So we’re including two marsh photos taken with a Galaxy S4 as well as iPhone 5c and iPhone 6 portrait shots to let you judge the quality for yourself. Keep in mind that all four of the images below are screen captures rather than the actual photographs. We came away from the experiment very impressed that the newer iPhones can hold their own against the Android devices with far better technical specs. While it’s still a bit of a knuckle drill to export a photo from your photo stream to iPhoto to email to a download to your desktop, it’s at least intuitive. Bottom Line: We no longer worry about photo quality when we don’t have an Android phone along for a trip.
With the camera testing behind us, that left us with two burning questions: how’s the WiFI and how’s the Bluetooth connectivity with cars?
Not to beat a dead horse, but WiFi typically hasn’t been Apple’s strong suit unless you happen to be using their access points. That seems to be resolved with iOS 8. 5G WiFi connectivity worked great with download and upload speeds matching the limits of our broadband service. That’s the good news.
The bad news is that Bluetooth is still a mess after years and years of problem reports. If anything, iOS 8 is a step backwards judging from the reports on Apple’s own support forum. Our results with one of the latest General Motors vehicles were terrible. While the iPhone 6 could be paired with the vehicle, nothing worked afterwards. No calls, no Pandora, nothing! When every $100 Android smartphone can pair with almost any vehicle and work, we get back to our initial question: "Can it make calls?" Unfortunately, unless you want to step back in time and hold your shiny, new iPhone 6 next to your ear, the answer is a resounding NO. And, yes, we jumped through all of the Apple hoops attempting to resolve the Bluetooth problems even though nobody should ever have to endure that! For $1,000, one would expect all of the basics on a smartphone to function correctly just as you expect your brakes and windshield wipers to work when you buy a new car. The fact that Apple has dropped the ball on Bluetooth for years is yet another reason we won’t be switching from Android anytime soon. In fact, the Bluetooth problem is a deal breaker for us so we’re returning the phone.
Finally, a word to the Apple fanboys. Don’t post comments. We won’t publish them. We are not Apple haters. Quite the contrary, we have more Apple hardware under our roof than any other brand. What Apple has done in the educational arena and to foster the image of technical support as a good thing is legendary. But you can’t drop the ball on the basics and expect people that depend upon technology to be impressed. Drop everything that deals with the shiny new watch for a few days and fix Bluetooth. It’s that important!
Originally published: Monday, October 13, 2014
Need help with Asterisk? Visit the PBX in a Flash Forum.
Special Thanks to Our Generous Sponsors
FULL DISCLOSURE: ClearlyIP, Skyetel, Vitelity, DigitalOcean, Vultr, VoIP.ms, 3CX, Sangoma, TelecomsXchange and VitalPBX have provided financial support to Nerd Vittles and our open source projects through advertising, referral revenue, and/or merchandise. As an Amazon Associate and Best Buy Affiliate, we also earn from qualifying purchases. We’ve chosen these providers not the other way around. Our decisions are based upon their corporate reputation and the quality of their offerings and pricing. Our recommendations regarding technology are reached without regard to financial compensation except in situations in which comparable products at comparable pricing are available from multiple sources. In this limited case, we support our sponsors because our sponsors support us.
BOGO Bonaza: Enjoy state-of-the-art VoIP service with a $10 credit and half-price SIP service on up to $500 of Skyetel trunking with free number porting when you fund your Skyetel account. No limits on number of simultaneous calls. Quadruple data center redundancy. $25 monthly minimum spend required. Tutorial and sign up details are here.
The lynchpin of Incredible PBX 2020 and beyond is ClearlyIP components which bring management of FreePBX modules and SIP phone integration to a level never before available with any other Asterisk distribution. And now you can configure and reconfigure your new Incredible PBX phones from the convenience of the Incredible PBX GUI.
VitalPBX is perhaps the fastest-growing PBX offering based upon Asterisk with an installed presence in more than 100 countries worldwide. VitalPBX has generously provided a customized White Label version of Incredible PBX tailored for use with all Incredible PBX and VitalPBX custom applications. Follow this link for a free test drive!
Special Thanks to Vitelity. Vitelity is now Voyant Communications and has halted new registrations for the time being. Our special thanks to Vitelity for their unwavering financial support over many years and to the many Nerd Vittles readers who continue to enjoy the benefits of their service offerings. We will keep everyone posted on further developments.
Some Recent Nerd Vittles Articles of Interest…
- Actually, the sales price for the 128GB iPhone 6 with AppleCare+ and sales tax came to a whopping $1,028.59 [↩]
Zero Day Vulnerability Protection and More: Introducing Cover Your Asterisk
It’s been a difficult couple of weeks for the Linux® and Asterisk® communities with the back-to-back disclosures of the BASH Shellshock bug and then the FreePBX® Asterisk Recording Interface (ARI) bug a few days later. Both of these vulnerabilities have been circulating in the wild for years. We won’t repeat Wikipedia’s Zero Day Attack analysis other than to note that what makes these particular bugs so scary is not only the fact that both went undetected and unpatched for years but also that the attack vectors for both bugs were so simple. Anyone with a web server exposed to the Internet that was running any flavor of Linux or any Asterisk server with the FreePBX GUI was fair game for a seriously compromised server.
For those with shared servers in a hosted environment running under cPanel, your web platform typically runs with the equivalent of root privileges which means that any web intrusion inherits the same server privileges that you as the administrator had. This is similar to the way FreePBX runs with Asterisk. The same user account used for web access controls all of the Asterisk assets on your server. While it’s convenient, it’s also dangerous whenever there’s a web vulnerability because the entire Asterisk platform has exposure.
We always chuckle when one of the anonymous forum trolls launches a tirade claiming that these alerts are nothing more than Monday morning quarterbacking disguised as Chicken Little. What’s more amazing is that anyone would take the comments of an anonymous poster seriously especially on a matter involving server security. It’s one thing to label folks as alarmists for suggesting that the sky is falling when it isn’t. It’s quite another to launch these anonymous personal attacks even when there is documented evidence that the Internet sky was indeed caving in. Kinda reminds us of the global warming naysayers when the polar ice caps are melting beneath their feet.
According to the naysayers, we’re all doomed when it comes to cyberterrorism so why fight it. Here’s why. While reacting to security vulnerabilities has always been a defensive game of cat and mouse, that doesn’t mean you shouldn’t proactively do what you can to patch serious security holes in your servers. The alternative is to give cybercriminals a blank check to launch bots from your server that generate spam or participate in large-scale zombie attacks on our most trusted resources whether they’re DNS root servers, utility infrastructure and our electric grid, banking assets, and even national security resources. So let’s circle back and address what you can do to assure that you’re part of the solution rather than part of the problem.
The Way It Is: Do I Need a Public Web Server with Asterisk?
For purposes of this discussion, our focus today is Asterisk server security. And the number one thing you can do to insulate your server from these vulnerabilities is to make certain that your web server is not exposed to Internet access by the general public. Neither Asterisk nor FreePBX requires public web server access to manage your server. In fact, neither Asterisk nor FreePBX requires any public access to your server to properly perform all required telecommunications functions. And the second paragraph above explains why this is especially dangerous with servers running both Asterisk and FreePBX.
So why do people still publicly expose their web servers and UDP ports 5060 and 10000-20000 to the Internet? As much as we hate to say it, it’s because it’s always been done that way. It’s also because there are a handful of SIP providers that still require UDP 5060 access to make and receive calls. Most do not! And even for those that do require UDP 5060 access, their requirements can be satisfied with a properly configured firewall that supports whitelisting of "safe" IP addresses for limited access. Incredible PBX comes preconfigured with a locked down WhiteList. The same can be added to PBX in a Flash by installing Travelin’ Man 3. We hope the other aggregations will follow suit. It’s long overdue.
Public web server access often is because there are more than a few (lazy) VoIP providers that install systems in a way that makes it easy for them to manage remote sites. Of course, a VPN would provide secure access to the same resources but that’s a little more work on the deployment end. With NeoRouter VPN, it’s a 5-minute job!
There also are companies with remote users or traveling salesmen that claim their servers must be open to the Internet to keep the company running. First, it’s hard to imagine a company whose salespeople don’t have cellphones that require no link to home base. Second, there are numerous solutions for safe connectivity with a home office: VPNs, FQDNs with dynamic DNS support, Port Knocker, and Travelin’ Man 4 to name just a few of the ones we previously have recommended. With the exception of the lazy VoIP installer, you will note that none of the above scenarios ever require web access to a VoIP server. So the rationale for public exposure of an Asterisk web server is all but non-existent.
The bottom line is that, if your server is not and has never been accessible from the Internet by typing its IP address into a public web browser and assuming your root password has not been compromised, then the BASH and ARI vulnerabilities are purely an academic discussion from your vantage point. Should you apply the patches anyway? Absolutely. Will your server be compromised if you don’t? Probably not… at least not from these two vulnerabilities.
Life Is Good: Why Do I Need ‘Cover Your Asterisk’
That brings us to our topic for today. Having said all of the above, how do you really know if your server has been compromised by some zero day attack vector that none of us yet know about? After all, there are tens of thousands of applications installed on a typical Linux server. And a zero day vulnerability could be hiding almost anywhere.
First, a few words about what Cover Your Asterisk is not. This application won’t detect previously compromised servers! Wearing a condom the day after your wild night on the town isn’t all that helpful. If your server has been running as a public web server for the last 5 years, then our best advice is to start with a fresh install to a new, secured server. Then manually copy the settings (not the files!) from your old server to the new platform. Now you’re ready to protect your server.
Second, more than a few words about the VoIP environment in which we find ourselves. If you’re running any of the so-called Asterisk aggregations including PBX in a Flash, Incredible PBX, AsteriskNOW, FreePBX Distro, or Elastix, then your server includes some flavor of the FreePBX GUI, a web-based application to manage and configure Asterisk. As part of the FreePBX GUI setup, you give FreePBX 2.11 and beyond an expansive set of privileges on your server. These include read, write, and delete access to all of your web assets, all of your VoIP-related MySQL database assets, and all of your Asterisk assets. You also grant FreePBX rights to inventory and monitor critical pieces of information about your server so that you can be informed about pertinent FreePBX updates. We don’t see this as a bad thing. But, even with the incredibly talented FreePBX development team, this application design can be dangerous for a number of reasons not the least of which is the events of the past week. Consider for a moment a scenario in which a disgruntled employee or a web vulnerability allows somebody to modify a critical Asterisk configuration file such as manager.conf which controls access to the Asterisk Manager Interface, or to adjust MySQL’s admin.ampusers table which controls web access to the FreePBX GUI, or even to insert a malicious module into FreePBX which "looks and feels" like part of FreePBX. When you don’t know what you’re looking for, detecting subtle changes can be extremely difficult even for the most talented people in the business. For everyone else, it’s next to impossible. This is especially true when the changes aren’t noticeable in the standard day-to-day operation of your server. That was what led us to conclude that an additional detection mechanism was essential to highlight hidden changes made to any of the critical components that make up the Asterisk platform. Thus was born Cover Your Asterisk.
The Elastix folks apparently weren’t comfortable with this arrangement and forked FreePBX years ago and moved to a self-managed environment. The drawback has been their pace of releasing updates and patches, and that apparently applies to the unaddressed ARI bug as well.
The remaining aggregations all function as we’ve described. Before we delve into Cover Your Asterisk, here’s a little known tip. On the output side, FreePBX is basically a code-generator for Asterisk. Once you’ve configured your server using the FreePBX GUI, there is no Asterisk-FreePBX linkage of which we’re aware that requires your web server to remain operational. That turns out to be a good thing. What this means is you can shut down Apache and still have a fully functional Asterisk server with all of the functionality of your FreePBX-designed configuration. Given the times in which we live, that may not be such a bad idea.
An Overview of Cover Your Asterisk
So what does Cover Your Asterisk do? What we’ve sought to do with this GPL2 application is to take a snapshot of your most valuable Asterisk and FreePBX assets and then create checksums of all the individual components. This includes the /etc/asterisk, /var/www/html/admin, and /var/lib/asterisk/agi-bin directories as well as the Asterisk DB and MySQL’s asterisk database. Periodically, you then run another script which compares your current setup to the previous snapshot and identifies the changes for further examination. Once you are satisfied that any reported changes are legitimate, you then take a new snapshot of your server and periodically check it to make certain no unexpected modifications have crept into your system. A duplicate of these production assets is always maintained in a separate directory structure (/etc/asterisk.snapshot) accessible only by root. It can easily be converted into a gzipped tarball: tar -cvzf cya.tar.gz /etc/asterisk.snapshot. Then simply store the tarball off site for a rainy day emergency… when the sky falls once again.
Because this application was designed for production servers, its testing and scope have been limited to the Asterisk 11 and FreePBX 2.11 platform. For our installed base, that translates into PIAF-Green with FreePBX 2.11 and all flavors of Incredible PBX 11 running atop CentOS, Scientific Linux, Ubuntu 14, Debian, and Raspbian platforms on both Intel and ARM hardware including the Raspberry Pi, BeagleBone Black, CuBox, and PogoPlug.
Installation and Operation of Cover Your Asterisk
Log into your Asterisk 11 server as root and issue the following commands to install the Cover Your Asterisk software:
cd /root wget http://incrediblepbx.com/cover-your-Asterisk.tar.gz tar zxvf cover-your-Asterisk.tar.gz rm -f cover-your-Asterisk.tar.gz
To take the original snapshot of your server, run: /root/protect-your-ASSets.sh
To check your current setup against the snapshot, run: /root/check-your-ASSets.sh
To compare a file with its snapshot, run: diff /dirpath/filename /etc/asterisk.snapshot/dirpath/filename
To restore a snapshot file to your current Asterisk configuration, run these commands:
cp -p /etc/asterisk.snapshot/etc/asterisk/filename /etc/asterisk/filename amportal restart
For Raspberry Pi and BeagleBone Black users, change the MySQL root password in both scripts:
sed -i 's|passw0rd|raspberry|' /root/protect-your-ASSets.sh sed -i 's|passw0rd|raspberry|' /root/check-your-ASSets.sh
Finally, let us close with several recommendations. First, before making changes to your server with FreePBX, always run check-your-ASSets.sh, correct any detected problems, and then run protect-your-ASSets.sh to create a new snapshot of your server. After making any changes with the FreePBX GUI, run check-your-ASSets.sh again to verify that the changes you sought to make were, in fact, the changes that actually were made to your server. Then finish up by taking a new snapshot. These scripts take less than 30 seconds to run on a typical server so this is not a cumbersome process.
Before you restore any snapshot file or if you are puzzled by any changes you see listed after running check-your-ASSets.sh, we strongly recommend that you first seek advice from the gurus on the PIAF Forum. They can help you identify the severity of the problem, if any, and recommend an appropriate course of action for correction of the problem.
Finally, a cautionary note. Cover Your Asterisk is still a project in development. This means there will be changes/improvements as the coming weeks go by. One wrinkle with updates is your previous snapshots will have to be checked before you update. And then the newest protect-your-ASSets.sh script will need to be run following the update. To keep track of future releases and what’s included, visit this development thread on the PIAF Forum. Enjoy!
Originally published: Monday, October 6, 2014
Need help with Asterisk? Visit the PBX in a Flash Forum.
Special Thanks to Our Generous Sponsors
FULL DISCLOSURE: ClearlyIP, Skyetel, Vitelity, DigitalOcean, Vultr, VoIP.ms, 3CX, Sangoma, TelecomsXchange and VitalPBX have provided financial support to Nerd Vittles and our open source projects through advertising, referral revenue, and/or merchandise. As an Amazon Associate and Best Buy Affiliate, we also earn from qualifying purchases. We’ve chosen these providers not the other way around. Our decisions are based upon their corporate reputation and the quality of their offerings and pricing. Our recommendations regarding technology are reached without regard to financial compensation except in situations in which comparable products at comparable pricing are available from multiple sources. In this limited case, we support our sponsors because our sponsors support us.
BOGO Bonaza: Enjoy state-of-the-art VoIP service with a $10 credit and half-price SIP service on up to $500 of Skyetel trunking with free number porting when you fund your Skyetel account. No limits on number of simultaneous calls. Quadruple data center redundancy. $25 monthly minimum spend required. Tutorial and sign up details are here.
The lynchpin of Incredible PBX 2020 and beyond is ClearlyIP components which bring management of FreePBX modules and SIP phone integration to a level never before available with any other Asterisk distribution. And now you can configure and reconfigure your new Incredible PBX phones from the convenience of the Incredible PBX GUI.
VitalPBX is perhaps the fastest-growing PBX offering based upon Asterisk with an installed presence in more than 100 countries worldwide. VitalPBX has generously provided a customized White Label version of Incredible PBX tailored for use with all Incredible PBX and VitalPBX custom applications. Follow this link for a free test drive!
Special Thanks to Vitelity. Vitelity is now Voyant Communications and has halted new registrations for the time being. Our special thanks to Vitelity for their unwavering financial support over many years and to the many Nerd Vittles readers who continue to enjoy the benefits of their service offerings. We will keep everyone posted on further developments.
Some Recent Nerd Vittles Articles of Interest…
Hold On to Your Wallet: Another Huge VoIP Phone Bill May Be Lurking
We interrupt our regularly scheduled content to bring you an urgent security alert. A couple days ago, a FreePBX® user reported unusual call activity. He traced the calls to a System Admin Dashboard module that was linked back to an IP address in the Netherlands. When the problem was reported, the FreePBX Community Manager quite accurately noted that it wasn’t FreePBX code. When a second user reported the exact same exploit, alarm bells apparently went off.
Further digging by the FreePBX Dev Team found that the legacy ARI module (once again) had been compromised, this time with a Remote Code Execution and Privilege Escalation exploit. Previous security vulnerabilities in this module led the PBX in a Flash developers many years ago to abandon the FreePBX security model in favor of Apache security so that we could totally block ARI access unless the user had administrator privileges. We want to stress that this wasn’t the fault of any of the current FreePBX developers. Instead, our move to Apache security was based upon our realization that this old legacy code was difficult to maintain because none of the original developers were still around. To their credit, the FreePBX developers have introduced a new User Control Panel with the strongest recommendation that the older ARI module be abandoned. Unfortunately, it still exists on all but the very latest FreePBX 12 systems including FreePBX 12 systems which were upgraded from a previous release. In addition, FreePBX 12 now provides checksum protection for all registered modules which will go a long way toward eliminating attacks such as this. So what can you do to protect your servers and your wallet today? For openers, upgrade your FreePBX fw_ari module NOW and clean the malicious module off your server:
rm -rf AMPWEBROOT/admin/modules/admindashboard amportal a ma upgrade fw_ari
If you encounter an error that FreePBX cannot connect to the Asterisk Manager, do the following from the Linux CLI:
sed -i 's|localhost|127.0.0.1|' /etc/freepbx.conf amportal restart amportal a r
Protecting Your Server from Remote VoIP Attacks
Let’s approach the long-term solution on several levels starting with vulnerability exposure. If you can access TCP ports 22 (SSH) and 80 (HTTP) and TCP/UDP port 5060 (SIP) of any of your Asterisk® and FreePBX-based servers anonymously from the Internet, you’re either nuts or rich.
We’ve cautioned against this for nearly a decade and yet even some developers still configure Asterisk and FreePBX-based servers with port 80 Internet exposure. Why? We can only assume it’s because it makes their job of accessing and maintaining these systems easy. Don’t do it! There still are numerous ways to gain access to the FreePBX GUI on any server. Here’s our short list…
Safest. Put your server behind a hardware-based firewall with no Internet port exposure. Then use a VPN to access the FreePBX GUI. In a perfect world, you can run a VPN on all of your VoIP phones so that you have end-to-end protection for your server and all of your users.
Safer. If a hardware-based firewall isn’t possible, use the Linux IPtables firewall and lock down all the ports on your server, especially TCP ports 22 and 80 and TCP/UDP port 5060. Then create a WhiteList of IP addresses that need access privileges. It’s worth stressing that Fail2Ban is completely worthless when it comes to security vulnerabilities such as the ARI RCE flaw because the bad guys walk right in without even being challenged for a password.
Safe. If you need remote access from various remote locations and these sites have dynamic IP addresses, then deploy the Port Knocker technology in addition to locking down your server with the IPtables firewall. This lets you gain temporary access to your server without providing a blank check (literally) to everybody on the Internet. There’s a reason it’s called the World Wide Web and not the Good Guys Web!
Worse. Exposing TCP port 5060 and UDP port 5060 to public Internet access is dangerous. Some providers unfortunately still require direct access to 5060 to make VoIP calls with SIP. TIP: Switch to a provider that allows SIP registrations so that you don’t have to expose port 5060 directly to the Internet EVER!
Worser. Pardon our grammar, but exposing TCP port 22 to public Internet access is a bad idea. At the very least, change the SSH port so that typical port scanners don’t discover your open SSH port. SSH has been compromised in the past. It probably will happen again, or it may have already happened and we just don’t (yet) know about it. Fail2Ban helps with SSH attacks, but it’s not infallible particularly when high performance servers are used in the attacks. Fail2Ban has to scan your logs and, before it can do that, it has to have a sufficient time slice to accomplish the scan, something that may never happen with an attack launched from a platform such as Amazon EC2.
Worst. Never expose TCP port 80 to public Internet access. If you do, then you obviously haven’t had the pleasure of trying to maintain a public web server. TIP: Unless you are a web expert or sleep with one, don’t do it EVER! Earlier this week BASH provided a revolving door to your Internet assets using simple web requests. Earlier this year, OpenSSL was compromised. There will be another vulnerability because it’s the easiest attack target. So it’s just a matter of time until your server is compromised unless you deploy an effective firewall that blocks public access to port 80.
Server Design Still Matters
For our own PBX in a Flash and Incredible PBX users, you can sleep well tonight. Today’s vulnerability is mostly academic for you. PBX in a Flash blocks all access to ARI without the maint password. Incredible PBX blocks all access to ARI through its IPtables WhiteList. It’s still a good idea to apply the FreePBX update just to be double-safe. And Incredible PBX users will have the patch applied the next time they log into their server as root. For everyone else using FreePBX, keep reading.
With our Incredible PBX open source project, we provide state-of-the-art security methodology. While it is not infallible, all of the code is freely available for any and all VoIP developers to review, improve, and deploy. We would encourage our fellow VoIP developers to do so. There were reasons in the past for not deploying Apache security. After all, it lacks the flexibility of the FreePBX security model, and Apache also can be compromised. But we can’t think of any reason today for not deploying a hardened, preconfigured IPtables firewall AND a functional WhiteList as an integral component in every VoIP server install. This is especially important for any product deployed with the FreePBX GUI. Our Travelin’ Man 3 WhiteList implementation has been available for more than 2½ years! While there are downsides to any sort of push technology, we also believe the Incredible PBX (opt-in) update service is worth a careful look. It has been a godsend for us. With every new login, the server checks for important updates and processes them unless the administrator chooses not to use the service.
Keep in mind that FreePBX masquerading as the asterisk user has complete read/write privileges to virtually every Asterisk and web asset on your server. Any compromise is extremely dangerous because the asterisk user on these platforms has such expansive privileges. We recently encountered a trojan authorization lurking inside the permissions list of Asterisk’s manager.conf table. The matter is still under investigation so we can’t reveal much more other than to note that the entry was harmless on the few affected Incredible PBX servers because of the hardened IPtables WhiteList which is a key component of every Incredible PBX server. Had this happened on a server with no firewall protection, the intruder would have had complete access to the Asterisk AMI which pretty much gives the intruder a blank check to Asterisk… using your checkbook. The silver lining was the Incredible PBX update utility which provided a quick way to remove the vulnerability.
The FreePBX Dev Team’s efforts to design and deploy a checksum-based system for FreePBX 12 modules is certainly a step in the right direction. We think more safeguards are warranted. We already are exploring new ways to provide alerts when critical Asterisk or FreePBX resources are modified on PBX in a Flash and Incredible PBX servers. Something akin to the Mac’s admin authorization requirement before critical Asterisk or FreePBX changes are made would be ideal, but we have some other ideas as well. Stay tuned!
Originally published: Wednesday, October 1, 2014
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