Palo Alto Firewall: macOS Updates NSURLErrorDomain error -1012

About a month ago, I enabled decryption on my Palo Alto firewall and limited it only to traffic to and from my MacBook Pro.  It’s worked well and provided great visibility into the vast amounts of encrypted traffic that we see nowadays.

So what’s this have to do with macOS?  Apple periodically releases updates and I had read that one was just released.  I checked my laptop and saw that I had a few updates to install for the iWork suite and Xcode.  Notably missing were notifications for the core macOS system updates.  I clicked on the “Updates” button again in the Mac App Store and received the following message.:

“Oh, the operation couldn’t be completed because of the NSURLErrorDomain error -1012?  Great, real helpful.”  I tried closing an reopening the App Store with no luck.  I thought maybe my laptop just wasn’t happy because I hadn’t rebooted in a while so I tried that, but still no luck.  I searched the interwebs and found a few forum posts, but nothing too helpful.  One post included lines from /var/log/install.log so I decided to check out what mine said.

2018-03-29 22:17:47-05 macbookpro softwareupdated[501]: Scan got error The operation couldn't be completed. (NSURLErrorDomain error -1012.)
2018-03-29 22:17:47-05 macbookpro softwareupdated[501]: Ramped updates marked
2018-03-29 22:20:23-05 macbookpro softwareupdated[501]: SUScan: Scan for client pid 501 (/System/Library/CoreServices/Software Update.app/Contents/Resources/softwareupdated)
2018-03-29 22:20:23-05 macbookpro softwareupdated[501]: Failed Software Update - Refusing invalid certificate from host: swscan.apple.com
2018-03-29 22:20:23-05 macbookpro softwareupdated[501]: Failed Software Update - Refusing invalid certificate from host: swscan.apple.com
2018-03-29 22:20:23-05 macbookpro softwareupdated[501]: SUScan: Elapsed scan time = 0.2
2018-03-29 22:20:23-05 macbookpro softwareupdated[501]: SUScan: Error encountered in scan: Error Domain=NSURLErrorDomain Code=-1012 "(null)" UserInfo={NSErrorFailingURLStringKey=https://swscan.apple.com/content/catalogs/others/index-10.13-10.12-10.11-10.10-10.9-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog, NSErrorFailingURLKey=https://swscan.apple.com/content/catalogs/others/index-10.13-10.12-10.11-10.10-10.9-mountainlion-lion-snowleopard-leopard.merged-1.sucatalog, NSLocalizedRecoverySuggestion=Make sure you’re connected to the Internet, and then try again., SUErrorRelatedCode=SUErrorCodeScanCatalogNotFound}

“Refusing invalid certificate from host: swscan.apple.com” — now we’re getting somewhere!  I knew immediately this was due to my Palo Alto decryption.  I checked my Monitor logs and confirmed that decryption was occurring on traffic to https://swscan.apple.com.

So how do I solve this?  A little digging and I found that Palo Alto maintains a predefined list of URLs to exclude from decryption in Device -> Certificate Management -> SSL Decryption Exclusion.   These are URLs that Palo Alto knows will cause issues if decryption is attempted.  Interestingly, searching for “apple” in this list showed a number of predefined apple.com URLs.  One was even described as “apple-appstore: pinned-cert” suggesting that perhaps Apple has updated the URL for this, causing my decryption to break my update process.

To add my own, I clicked “Add” at the bottom, and entered the following.:

Committed the change and tried updating my laptop once more.  This time, it worked!

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Eric’s Top 7 Ways To Get Ready For Security Awareness This Summer

Once upon a time, I believed that security awareness trainings were simply boring computer-based training videos that compliance requirements forced upon companies.  You’d simply “next, next, next” your way through and learn nothing of value.  However, in my current role I am directly responsible for developing the security program for my company and with a small team, I’ve realized how important it is to build a security culture to move my initiatives forward. To that end, security awareness trainings (if done properly) can be an effective method for educating employees and developing a security culture.

Given that I actually want people to learn about security and help me achieve my security goals, I set out to create an engaging and entertaining training.  Having done these for over a year now, I’ve found that people generally just aren’t knowledgeable about security and if you show them how it applies to their everyday lives and how to do things in a more secure manner, they become far more interested and engaged.

So here’s what I think makes for an effective security awareness training.

  1. Deliver it live and in-person.  Granted, this isn’t always possible, especially if you work for a large, geographically spread out company. But if you can do this, I highly recommend it.  We as security professionals don’t like sitting through computer-based trainings or vendor-purchased cookie-cutter security programs, so what makes us think our coworkers would enjoy it any better?  Doing it live puts a face to your company’s security program and allows for back-and-forth discussion and a chance for people to ask questions.  These are good things, I promise.
  2. Make it an integral part of new hire orientation.  By making this part of a new hire’s first day, it tells each new employee that your company takes security seriously and ultimately helps to build a culture of security.  Work with your HR department and explain why this is critical.  You’ll likely be able to lean on any compliance controls you may be required to follow (SOX, PCI, etc.) that mandate some kind of security training for new employees.
  3. Introduce the Security Team. Explain the purpose of the team and why the team exists.  I tell everyone that our team’s goal is to protect the company’s assets to enable the business to succeed.  That’s easily understandable and free of any technical jargon or fancy language.  It also ties it back to the business and its overall goal of wanting to succeed to increase profits.  If the team is small enough, mention names and roles.  If it’s large, outline the roles at a high level.
  4. Explain why security matters.  Give examples and then give more examples.  Talk about breaches and malware that’s been in the news.  In my training, I do this and cover interesting statistics and trends that have been reported by reputable security sources.  These include how long an attacker goes undetected on average and how often a weak password leads to compromise.  These statistics combined with my own commentary illustrate how security is critical to any business and that the struggle is in fact real.
  5. Discuss why someone would target your company.  If your company generates any kind of revenue or holds valuable assets and information, you can be certain that someone will target it.  Think about what your company does and what would be of most interest to an attacker.  I tell people that our company’s assets include our people, products, money, data, and brand reputation.  Each of these would be impacted by a security breach.
    The best way to drive this point home is by sharing a past security incident that occurred at your company to explain how the company’s already been successfully compromised.  Naturally, you should obtain the approval of your executive and legal teams prior to sharing this type of information.  One type of breach that most are comfortable with sharing is regarding any successful phishing scams as this is a common type of attack that most people have already experienced both in business and in their personal lives.
  6. Present the safeguards in place and provide actionable steps to secure company assets.  You’ve worked hard to implement some amazing security technologies and controls.  While not everyone will understand (or care) about each of these, highlight the more user-facing ones.  In my training, I discuss the importance of patching and the periodic  prompts to install updates, the convenience of our single sign-on solution, how to create strong passwords using passphrases, how to securely access mobile email through our MDM solution, the importance of using our secure file storage and sharing solution, and how to quickly lock their screen to limit unauthorized access.  These are all relevant and actionable steps that end users can take to secure valuable company assets.
  7. Most importantly, engage people and include them as part of the Security Team.  Present the material in an engaging manner.  While security is a serious topic, that doesn’t mean it has to be dry.  Use humor, tell stories, answer questions.  And always with a smile, even if HR scheduled for you to talk at 8 AM at the last minute. 😛  Easier said than done, sure, but this goes a long long way to keeping people interested in what is otherwise a typically bland topic for most.
    Finish by telling them that they’re not only part of their respective department/team but now that they’ve taken your training, they’re also part of the Security Team.  Explain that you can’t secure everything on your own and that you need everyone’s help to prevent and respond to security incidents.  Reiterate that security is not just one team’s responsibility, but in fact, everyone’s responsibility.

I’ve applied these methods for over a year in my own trainings and I’ve seen people engage my team in ways I never experienced in previous roles.  People ask for our opinions on security regarding technologies and processes and they actively report suspicious activities be it strange emails or abnormal computer behavior.  We’ve been told by others that they support security and are grateful for the efforts of my team.

This is truly amazing, and I have no doubt that these 30-45 minute trainings that I deliver a few times each month have played a significant part in this.  You may think you’re a 1337 haxx0r that can defend your company’s network on your own, but you’re fooling yourself if you do.  You may be the security expert and all around technical wizard, but if people don’t value security or understand what security’s purpose is, your own people will continue to be your biggest security hole.  Why not spend the time and effort to flip that around and make them one of security’s biggest assets?

 

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Palo Alto Firewall: External Dynamic Lists

I recently attended Palo Alto’s annual Ignite conference for the first time.  It was a great experience for learning about best practices and networking with others.  One of the things I learned was Palo Alto’s way of handling basic threat intelligence feeds.  When I say basic I’m referring to IPs, domains, and URLs.

It turns out that with an active Threat Prevention license, you’ll immediately get access to two Palo Alto-provided threat intelligence feeds.  I’ve listed them below with their provided-descriptions.:

  • Palo Alto Networks – Known malicious IP addresses: Malicious IP addresses that are currently used almost exclusively by malicious actors for malware distribution, command-and-control, or for launching various attacks.
  • Palo Alto Networks – High risk IP addresses: High risk IP addresses, shared IP addresses that have recently been featured in threat activity advisories distributed by high-trust organizations, however Palo Alto Networks does not have direct evidence of maliciousness.

There are of course a myriad of these types of malicious IP lists available.  Lucky for us, someone has compiled several of these sources and formatted the data such that Palo Alto can properly ingest them.  I added most of these to my own configuration and added one from abuse.ch’s Ransomeware Tracker.

It’s pretty easy to add these lists, just follow the steps below.

Create External Dynamic Lists

  1. Once logged into the Palo Alto firewall, navigate to Objects -> External Dynamic Lists.
  2. If you have a valid Threat Prevention license, you should already see the two Palo Alto-provided lists noted above.  Click Add to add a custom external dynamic list.
  3. Populate the required fields:
    • Name: Give a name for the list.
    • Type: Select the type of list, for this entry we’ll use IP List.
    • Description: Enter a helpful description for the list.
    • Source: This is the URL of the threat intelligence feed.  It is preferred that https URLs be used so that the feeds are not compromised in transit.  However, I did notice that the firewall would not properly download from the https-version of ransomwaretracker.abuse.ch.
    • Server Authentication: The Certificate Profile to authenticate to the Source. This is optional.
    • Repeat: The frequency for updating the list.  I’ve set all of mine to hourly.

    You can optionally click on Test Source URL to confirm that the firewall can successfully reach the URL.

  4. Once finished, click OK to save the new list.
  5. Repeat for any additional threat intelligence feeds you may have.
  6. Optional. Select a rule and click Import Now to download list data and verify everything is in working order.
  7. Commit the changes to save the configuration.

Note: There are limits to the list capacities.  At the time of this writing they are as follows:

  • IPs: 50,000
  • Predefined IPs: 20,000
  • Domains: 50,000
  • URLs: 50,000

Now that we’ve got our External Dynamic Lists created, we need to create a security policy rule that blocks traffic to the malicious IPs contained in these lists.

Create Security Policy Rule to block traffic to External Dynamic Lists

  1. Navigate to Policies -> Security and click Add.  First populate the General tab.
  2. In the Source tab, click Add to add your trusted internal zones and/or addresses.  In my case, my internal network is all within the Trust-L3 zone.
  3. In the Destination tab, click Add to your untrusted zones and addresses.  This step is critical as you’ll want to add both the zone AND the addresses from the External Dynamic Lists.  Completing only the Destination Zone and NOT the Destination Address will result in all outbound traffic from being blocked.  You probably don’t want that. 😛
    In my case, anything outside my internal network, namely the Internet, is referred to as the Untrust-L3 zone.  Under Destination Address, click Add and find the lists we created earlier under the External Dynamic List section.

    Repeat this step for each of the lists you’d like to add.

  4. In the Actions tab, select Deny under Action Setting.
  5. Click OK to save the new policy rule.  Place your new rule at the top of all other rules so that it supersedes any Internet outbound rules.
  6. Commit the changes to save the configuration.
  7. Now let’s test our rule to ensure we’re blocking traffic.  I’ve taken one of the IPs from the list above and tried pinging it.
➜ ~ ping 103.232.215.140
PING 103.232.215.140 (103.232.215.140): 56 data bytes
Request timeout for icmp_seq 0
Request timeout for icmp_seq 1
Request timeout for icmp_seq 2
Request timeout for icmp_seq 3

Looks pretty good from the client side.  Let’s see what the firewall sees.

Success!  Looks like everything’s working as expected.  Assuming our External Dynamic Lists are of high quality, any hits to this rule should be a strong indicator of possible compromise on our network.  We could update our security policy rule to send us an email anytime this rule was triggered.

To take this even further, you could sign up for an open source threat intelligence repository like Critical Stack’s Intel feeds and write a script to download this data, format it for Palo Alto, and then use Palo Alto’s API to automatically generate and update these lists in your firewall.  Perhaps a future blog post. 🙂

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