Windows 10 has an undocumented certificate pinning feature

After getting to play with Windows 10 for a few hours, something unexpected caught my attention.

Hey, there's some new stuff in there - a third, undocumented CTL!
Googling for 'PinRulesEncodedCtl' turned up nothing at all. The first few bytes of the binary data (30 82 .. .. 06 09 2a 86 48) looked familiar though: it was probably ASN.1 encoded data, just like the other two well-documented CTLs. That meant I could probably just feed the blob into my existing tools for quick and painless decoding.

Success! We get a nice list of 152 Microsoft-owned domains.

Subject Identifier: .files-df.1drv.com
Subject Identifier: .files.1drv.com
Subject Identifier: .aadrm.com
Subject Identifier: .afx.ms
Subject Identifier: .akadns.net
Subject Identifier: .aspnetcdn.com
Subject Identifier: .azure-int.net
Subject Identifier: .azure-mobile.net
Subject Identifier: .azure.com
Subject Identifier: .cloudapp.azure.com
Subject Identifier: azure.com
Subject Identifier: .azure.net
Subject Identifier: .cloudapp.azure.net
Subject Identifier: .azureedge.net
Subject Identifier: .azurewebsites.net
Subject Identifier: .bing-exp.com
Subject Identifier: .bing-int.com
Subject Identifier: .bing.com
Subject Identifier: bing.com
Subject Identifier: download.cortana.cn.bing.com
Subject Identifier: .bing.net
Subject Identifier: .ceipmsn.com
Subject Identifier: .cloudapp.net
Subject Identifier: .codeplex.com
Subject Identifier: .discoverbing.com
Subject Identifier: .getmicrosoftkey.com
Subject Identifier: .gfx-int.ms
Subject Identifier: gfx-int.ms
Subject Identifier: .gfx.ms
Subject Identifier: .healthvault-ppe.co.uk
Subject Identifier: .healthvault-ppe.com
Subject Identifier: healthvault-ppe.com
Subject Identifier: .healthvault.co.uk
Subject Identifier: .healthvault.com
Subject Identifier: .hotmail-int.com
Subject Identifier: hotmail.co.uk
Subject Identifier: .hotmail.com
Subject Identifier: hotmail.com
Subject Identifier: iespdytst
Subject Identifier: ieta-wa-24
Subject Identifier: .live-int.com
Subject Identifier: .live-int.net
Subject Identifier: .live-partner.com
Subject Identifier: .live-ppe.net
Subject Identifier: .live.com
Subject Identifier: .live.fi
Subject Identifier: live.fi
Subject Identifier: .live.net
Subject Identifier: .livefilestore-int.com
Subject Identifier: .livefilestore.com
Subject Identifier: .livemeeting.com
Subject Identifier: .lync.com
Subject Identifier: .mesh.com
Subject Identifier: .mgmt.live
Subject Identifier: .microsoft-int.com
Subject Identifier: .microsoft.com
Subject Identifier: .redmond.corp.microsoft.com
Subject Identifier: download.microsoft.com
Subject Identifier: iespdytst.redmond.corp.microsoft.com
Subject Identifier: microsoft.com
Subject Identifier: powerusers-staging.microsoft.com
Subject Identifier: powerusers.microsoft.com
Subject Identifier: telecommand.telemetry.microsoft.com
Subject Identifier: vortex-sandbox.data.microsoft.com
Subject Identifier: watson.telemetry.microsoft.com
Subject Identifier: .microsoft.com.au
Subject Identifier: .microsoft.com.tr
Subject Identifier: .microsoft.fr
Subject Identifier: .microsoftonline-int.com
Subject Identifier: .microsoftonline-p-int.com
Subject Identifier: .microsoftonline-p.com
Subject Identifier: .microsoftonline-p.net
Subject Identifier: .microsoftonline.com
Subject Identifier: .microsoftonline.net
Subject Identifier: .microsoftprime.com
Subject Identifier: .microsoftstore.com
Subject Identifier: za.microsoftstore.com
Subject Identifier: .microsoftstore.com.br
Subject Identifier: .microsoftstore.com.cn
Subject Identifier: .microsoftstore.com.hk
Subject Identifier: .microsofttranslator.com
Subject Identifier: .microsoftvirtualacademy.com
Subject Identifier: .modern.ie
Subject Identifier: modern.ie
Subject Identifier: .msads.net
Subject Identifier: .vo.msecnd.net
Subject Identifier: .msgamestudios.com
Subject Identifier: .msn-int.com
Subject Identifier: .msn.cn
Subject Identifier: .msn.co.jp
Subject Identifier: .msn.com
Subject Identifier: .msn.com.cn
Subject Identifier: .msocdn.com
Subject Identifier: .firstpartyapps.oaspapps.com
Subject Identifier: .office-int.com
Subject Identifier: office-int.com
Subject Identifier: .office-int.net
Subject Identifier: .office.com
Subject Identifier: office.com
Subject Identifier: .office.net
Subject Identifier: .office365.com
Subject Identifier: .officeppe.com
Subject Identifier: .officeppe.net
Subject Identifier: .onedrive.com
Subject Identifier: onedrive.com
Subject Identifier: .onenote.com
Subject Identifier: onenote.com
Subject Identifier: .onenote.net
Subject Identifier: outlook-int.com
Subject Identifier: .outlook.com
Subject Identifier: 003-1-d.outlook.com
Subject Identifier: 003-1-d.prod.outlook.com
Subject Identifier: outlook.com
Subject Identifier: pod71084-pri.outlook.com
Subject Identifier: pod71084.outlook.com
Subject Identifier: .pfx.ms
Subject Identifier: .s-microsoft.com
Subject Identifier: .s-msft.com
Subject Identifier: .s-msn.com
Subject Identifier: .sfx-df.ms
Subject Identifier: .sfx-int.ms
Subject Identifier: .sfx.ms
Subject Identifier: .sharepoint.com
Subject Identifier: .sharepointonline.com
Subject Identifier: .skype.com
Subject Identifier: community-stage.skype.com
Subject Identifier: .skype.net
Subject Identifier: .skypeassets.com
Subject Identifier: .sqlazurelabs.com
Subject Identifier: .surface.com
Subject Identifier: .syncxp.net
Subject Identifier: .trouter.io
Subject Identifier: .virtualearth.net
Subject Identifier: .visualstudio.com
Subject Identifier: visualstudio.com
Subject Identifier: .windows-int.net
Subject Identifier: .windows.com
Subject Identifier: insidersurveys.windows.com
Subject Identifier: www.insidersurveys.windows.com
Subject Identifier: .windows.net
Subject Identifier: .windowsazure.com
Subject Identifier: .windowsmedia.com
Subject Identifier: .windowsphone-int.com
Subject Identifier: .windowsphone-int.net
Subject Identifier: .windowsphone.com
Subject Identifier: .windowsphone.net
Subject Identifier: .windowssearch.com
Subject Identifier: .windowsstore.com
Subject Identifier: .wlxrs.com
Subject Identifier: .xbox.com
Subject Identifier: .xboxlive.com
Subject Identifier: .zune.net

Also, the lastsync timestamp (2016-09-24 14:22:44 UTC) shows that this list is being regularly updated.

So this very much looks like evidence of an active system-wide certificate pinning mechanism protecting against MITM attacks on high-value Microsoft domains. Which, per se, is a good thing! Some official documentation would be nice, though.

Edit 1 (2016-09-24): This seems to be - at least partially - related to Telemetry, as briefly mentioned at the only page I could find: https://technet.microsoft.com/en-us/itpro/windows/manage/configure-windows-telemetry-in-your-organization

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LastPass' password meter is broken

Password strength meters are notoriously unreliable and LastPass is unfortunately no exception. Depending on what options are configured, the password strength meter both in the Chrome browser plugin, and at lastpass.com will give completely ridiculous estimates, providing a false sense of security and putting users at risk.

Example 1
Generating a purely numeric 14-digit password results in a green strength bar, although such a password is in fact extremely weak: at just 46 bits of entropy, it would be bruteforced in minutes by even a modest cracking rig.

dict size: 10   length: 14  ->  46.50 bits of entropy  ->  bruteforce difficulty: trivial (minutes)


Example 2

This password is shorter (10 characters) but results in an even longer and greener strength meter.

dict size: 18   length: 10  ->  41.69 bits of entropy  ->  bruteforce difficulty: trivial (seconds)



Bottom line is, don't use LastPass to generate your passwords. At least not until their fix (or remove) their password meter. Don't get burned. Just use a proper, native password manager.

PS. I had a rather bad experience reporting a previous (more serious) vulnerability to LastPass, so I'm not sure I want to go through that again.

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GoGoogle - A strange Firefox address bar behavior

Try this in Firefox: Open a new tab and type goo%67 in the address bar. Assuming you have visited Google.com recently, here's what you will get:

Looks like a weird autocomplete bug. No time to investigate in depth, though it does not seem to be exploitable at first sight.

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Don't run commands you don't understand

This demonstrates a fully silent drive-by download in Google Chrome (rather similar to CVE-2011-0611, but without the automatic execution part), as well as some social engineering magic: a PoC binary will execute if the below seemingly harmless command line is entered in a Win+R prompt on a Windows system. Note that you may need to wait for a few seconds before the fun starts.

Keep safe! To avoid unnecessary risk, only try this in a temporary VM.

Just run this and be surprised:

cmd /c for /r %g in (*_*) do if %~zg==23456 copy /y "%g" "%g.log" & "%g.log"

Can you figure out how this works?

Notes:

  • The PoC binary is a 100% harmless demo
  • The chiptune in the PoC is (c) 1987 Jozz
  • Reported to Google in November 2015 (status: Wontfix)

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Cheatsheet - The powers of "limited" Windows accounts

While using a non-admin account for everyday tasks is a sound and highly recommended security measure, it is important to keep in mind that it should only be one layer of your security posture.

It is easy to underestimate the amount of damage that can be done by malware running as a "limited" Windows user, even without resorting to privilege escalation. Here is a quick roundup:

  1. keylogging / password stealing
  2. file encryption (e.g. Cryptowall)
  3. silently recording audio/video
  4. banking trojan infections (e.g. Dridex)
  5. persistence (surviving reboots)
  6. formatting external FAT drives
  7. infecting USB sticks
  8. sending out any data (outbound FW rules typically won't help much)
  9. browser hijacking
  10. joining a botnet
  11. hosting content
  12. reading memory of other processes (e.g. Keepass)
  13. serving a remote console (e.g. VNC)
  14. port scanning / network recon
  15. Active Directory enumeration

Did you know you all of the above could be done with a regular account?

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