Posts Tagged 'Ddos'

November 2, 2012

The Trouble with Open DNS Resolvers

In the last couple of days, there's been a bit of buzz about "open DNS resolvers" and DNS amplification DDoS attacks, and SoftLayer's name has been brought up a few times. In a blog post on October 30, CloudFlare explained DNS Amplification DDoS attacks and reported the geographic and network sources of open DNS resolvers that were contributing to a 20Gbps attack on their network. SoftLayer's AS numbers (SOFTLAYER and the legacy THEPLANET-AS number) show up on the top ten "worst offenders" list, and Dan Goodin contacted us to get a comment for a follow-up piece on Ars Technica — Meet the network operators helping to fuel the spike in big DDoS attacks.

While the content of that article is less sensationalized than the title, there are still a few gaps to fill about when it comes to how SoftLayer is actually involved in the big picture (*SPOILER ALERT* We aren't "helping to fuel the spike in big DDoS attacks"). The CloudFlare blog and the Ars Technica post presuppose that the presence of open recursive DNS resolvers is a sign of negligence on the part of the network provider at best and maliciousness at worst, and that's not the case.

The majority of SoftLayer's infrastructure is made up of self-managed dedicated and cloud servers. Customers who rent those servers on a monthly basis have unrestricted access to operate their servers in any way they'd like as long as that activity meets our acceptable use policy. Some of our largest customers are hosting resellers who provide that control to their customers who can then provide that control to their own customers. And if 23 million hostnames reside on the SoftLayer network, you can bet that we've got a lot of users hosting their DNS on SoftLayer infrastructure. Unfortunately, it's easier for those customers and customers-of-customers and customers-of-customers-of-customers to use "defaults" instead of looking for, learning and implementing "best practices."

It's all too common to find those DNS resolvers open and ultimately vulnerable to DNS amplification attacks, and whenever our team is alerted to that vulnerability on our network, we make our customers aware of it. In turn, they may pass the word down the customer-of-customer chain to get to the DNS owner. It's usually not a philosophical question about whether DNS resolvers should be open for the greater good of the Internet ... It's a question of whether the DNS owner has any idea that their "configuration" is vulnerable to be abused in this way.

SoftLayer's network operations, abuse and support teams have tools that flag irregular and potentially abusive traffic coming from any server on our network, and we take immediate action when we find a problem or are alerted to one by someone who sends details to abuse@softlayer.com. The challenge we run into is that flagging obvious abusive behavior from an active DNS server is a bit of a cat-and-mouse game ... Attackers cloak their activity in normal traffic. Instead of sending a huge amount of traffic from a single domain, they send a marginal amount of traffic from a large number of machines, and the "abusive" traffic is nearly impossible for even the DNS owner to differentiate from "regular" traffic.

CloudFlare effectively became a honeypot, and they caught a distributed DNS amplification DoS attack. The results they gathered are extremely valuable to teams like mine at SoftLayer, so if they go the next step to actively contact the abuse channel for each of the network providers in their list, I hope that each of the other providers will jump on that information as I know my team will.

If you have a DNS server on the SoftLayer network, and you're not sure whether it's configured to prevent it from being used for these types of attacks, our support team is happy to help you out. For those of you interested in doing a little DNS homework to learn more, Google's Developer Network has an awesome overview of DNS security threats and mitigations which gives an overview of potential attacks and preventative measures you can take. If you're just looking for an easy way to close an open recursor, scroll to the bottom of CloudFlare's post, and follow their quick guide.

If, on the other hand, you have your own DNS server and you don't want to worry about all of this configuration or administration, SoftLayer operates private DNS resolvers that are limited to our announced IP space. Feel free to use ours instead!

-Ryan

June 25, 2012

Tips from the Abuse Department: Part 2 - Responding to Abuse Reports

If you're a SoftLayer customer, you don't want to hear from the Abuse department. We know that. The unfortunate reality when it comes to hosting a server is that compromises can happen, mistakes can be made, and even the most scrupulous reseller can fall victim to a fraudulent sign-up or sly spammer. If someone reports abusive behavior originating from one of your servers on our network, it's important to be able to communicate effectively with the Abuse department and build a healthy working relationship.

Beyond our responsibility to enforce the law and our Acceptable Use Policy, the Abuse department is designed to be a valuable asset for our customers. We'll notify you of all valid complaints (and possibly highlight security vulnerabilities in the process), we'll assist you with blacklist removal, we can serve as a liaison between you and other providers if there are any problems, and if you operate an email-heavy platform or service, we can help you understand the steps you need to take to avoid activity that may be considered abuse.

At the end of the day, if the Abuse department can maintain a good rapport with our customers, both our jobs can be easier, so I thought this installment in the "Tips from the Abuse Department" series could focus on some best practices for corresponding with Abuse from a customer perspective.

Check Your Tickets

This is the easiest, most obvious recommendation I can give. You'd be surprised at how many service interruptions could be avoided if our customers were more proactive about keeping up with their open tickets. Our portal is a vital tool for your business, so make sure you are familiar with how to access and use it.

Keep Your Contact Information Current

Our ticket system will send notifications to the email address you have on file, so making sure this information is correct and current is absolutely crucial, especially if you aren't in the habit of checking the ticket system on a regular basis. You can even set a specific address for abuse notifications to be sent to, so make use of this option. The quicker you can respond to an abuse report, the quicker the complaint can be resolved, and by getting the complaint resolved quickly, you avoid any potential service interruption.

If we are unable to reach you by ticket, we may need to call you, so keep your current phone numbers on file as well.

Provide Frequent Updates

Stay in constant communication in the midst of responding to an abuse report, and adhere to the allotted timeline in the ticket. If we don't see updates that the abusive behavior is being addressed in the grace period we are able to offer, your server is at risk of disconnection. By keeping us posted about the action you're taking and the time you need to resolve the matter, we're able to be more flexible.

If a customer on your servers created a spamming script or a phishing account, taking immediate steps to mitigate the issue by suspending that customer is another great way to respond to the process while you're performing an investigation of how that activity was started. We'll still want a detailed resolution, but if the abuse is not actively ongoing we can work with you on deadlines.

Be Concise ... But Not Too Concise

One-word responses: bad. Page long responses: also not ideal. If given the option we would opt for the latter, but your goal should be to outline the cause and resolution of any reported abusive activity as clearly and succinctly as possible in order to ease communication and expedite closing of the ticket.

Responding to a ticket with, "Fixed," is not sufficient to for the Abuse department to consider the matter resolved, but we also don't need a dump of your entire log file. Before the Abuse team can close a ticket, we have to see details of how the complaint was resolved, so if you don't provide those details in your first response, you can bet we'll keep following up with you to get them. What details do we need?

Take a Comprehensive Approach

In addition to stopping the abusive activity we want to know:

  1. How/why the issue occurred
  2. What steps are being taken to prevent further issues of that nature

We understand that dealing with abuse issues can often feel like a game of Whack-A-Mole, but if you can show that you're digging a bit deeper and taking steps to avoid recurrence, that additional work is very much appreciated. Having the Abuse department consider you a proactive, ethical and responsible customer is a worthy goal.

Be Courteous

I'm ending on a similar note to my last blog post because it's just that important! We understand getting an abuse ticket is a hassle, but please remember that we're doing our best to protect our network, the Internet community and you.

Unplugging your server is a last resort for us, and we want to make sure everyone is on the same page to prevent us from getting to that last resort. In the unfortunate event that you do experience an abuse issue, please refer back to this blog — it just might save you some headaches and perhaps some unnecessary downtime.

-Jennifer

June 18, 2012

Tips from the Abuse Department: Part 1 - Reporting Abuse

SoftLayer has a dedicated team working around the clock to address complaints of abuse on our network. We receive these complaints via feedback loops from other providers, spam blacklisting services such as Spamcop and Spamhaus, various industry contacts and mailing lists. Some of the most valuable complaints we receive are from our users, though. We appreciate people taking the time to let us know about problems on our network, and we find these complaints particularly valuable as they are non-automated and direct from the source.

It stands to reason that the more efficient people are at reporting abuse, the more efficient we can be at shutting down the activity, so I've compiled some tips and resources to make this process easier. Enjoy!

Review our Legal Page

Not only does this page contain our contact details, there's a wealth of information on our policies including what we consider abuse and how we handle reported issues. For starters, you may want to review our AUP (Acceptable Use Policy) to get a feel for our stance on abuse and how we mitigate it.

Follow Proper Guidelines

In addition to our own policies, there are legal aspects we must consider. For example, a claim of copyright infringement must be submitted in the form of a properly formatted DMCA, pursuant to the Digital Millennium Copyright Act. Our legal page contains crucial information on what is required to make a copyright claim, as well as information on how to submit a subpoena or court order. We take abuse very seriously, but we must adhere to the law as well as our privacy policy in order to protect our customers' businesses and our company from liability.

Include Evidence

Evidence can take the form of any number of things. A few common examples:

  • A copy of the alleged spam message with full headers intact.
  • A snippet from your log file showing malicious activity.
  • The full URL of a phishing page.

Without evidence that clearly ties abusive activity to a server on our network, we are unable to relay a complaint to our customer. Keep in mind that the complaint must be in a format that allows us to verify it and pass it along, which typically means an email or hard copy. While our website does have contact numbers and addresses, email is your best bet for most types of complaints.

Use Keywords

We use a mail client specifically developed for abuse desks, and it is configured with a host of rules used for filtering and prioritization. Descriptive subject lines with keywords indicating the issue type are very useful. Including the words "Spam," "Phishing" or "Copyright" in your subject line helps make sure your email is sent to the correct queue and, if applicable, receives expedited processing. Including the domain name and IP address in the body of the email is also helpful.

Follow Up

We work hard to investigate and resolve all complaints received however, due to volume, we typically do not respond to complaining parties. That said, we often rely on user complaints to determine if an issue has resumed or is ongoing so feel free to send a new complaint if activity persists.

Be Respectful

The only portion of your complaint we are likely to relay to our customer is the evidence itself along with any useful notes, which means that paragraph of profanity is read only by hardworking SoftLayer employees. We understand the frustration of being on the receiving end of spam or a DDOS, but please be professional and try to understand our position. We are on your side!

Hopefully you've found some of this information useful. When in doubt, submit your complaint to abuse@softlayer.com and we can offer further guidance. Stay tuned for Part 2, where I'll offer suggestions for SoftLayer customers about how to facilitate better communication with our Abuse department to avoid service interruption if an abuse complaint is filed against you.

-Jennifer

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