PKIDo You Know your Exposure?

Kent King

Information Security Manager

Public Key Infrastructure

Authentication

Confidentiality

Integrity

Nonrepudiation Gawker.com

Certificates Enable

Secure data transfers TLS, SSL, https, VPN, sFTP, ssh

Code signing

Origination

Validation

Non-Repudiation

Certificate Authorities

Trust in the certificate itself

Validate owner of certificate

Auditability

Revocation & Renewal

Intermediate CAs

Self-Signed Certificates

Certificates Are Internet Glue

Digital certificates are everywhere TLS

Wireless

Mobile devices

IoT/Embedded devices

Code signing

Trusted root certificates – because you can’t always internet Browsers and OS use different root stores

Do you know what is in your root store?

What’s in Your Root Store?

http://www.zdnet.com/article/google-banishes-chinas-main-digital-certificate-authority-cnnic/

Self-Signed Certificates

Who is the owner? Did the issuer have the permission of the domain owner?

What is the status? How recently was it issued? How long is it valid?

Contain both public and private key data

Vendor failure: Superfish

http://blog.erratasec.com/2015/02/extracting-superfish-certificate.html#.VuXin-IrLct

Self-Signed Browser Warning

Certificates – The Bad

Certificate Authorities Compromised 2011 – Diginotar, Comodo

2014 - NIC of India -intermediate CA

Root Certificate pain Google revoked 20 year Verisign Cert

Implementation errors Heartbleed, DROWN

http://www.darkreading.com/attacks-breaches/digital-certificate-authority-hacked-dozens-of-phony-digital-certificates-issued/d/d-id/1136244

• Vulnerable algorithms: MD5 and SHA-1

• Malware steals legitimate and installs malicious certificates

• Process errors • A test or self-signed certificate

gets into production

• Letting your certificates expire

• 2013 - Azure

More bad…

http://arstechnica.com/security/2015/10/sha1-crypto-algorithm-securing-internet-could-break-by-years-end/

Real attacks

Stuxnet – Certificate Theft Signed code

Operation Emmental – Fake Certificates Malware places certificate and no warning

is seen at phishing web sites

POODLE – Protocol attacks Goodbye SSL v3

Man In The Middle The story of Bob, Alice and Mallory

http://www.computerweekly.com/news/4500242932/Google-warns-of-fake-digital-certificates

Pidgin, Dsniff, Fiddler2, Subterfuge

Threat Review

Certificate Compromise CA failures

Malware

Certificate Insertion

Vulnerable Algorithms

Implementation Issues

Process Errors

Ensuring validation and revocation status

If You Ever See a Revoked Certificate

Mitigation

Attack surface

Study of routers, modems, IP cameras, VoIP phones and other devices showed that over 3M devices used one of 150 TLS private keys.

The same study saw just less than 1M SSH private keys using 80 private keys.

230 keys to control our planet?

https://nakedsecurity.sophos.com/2015/11/30/millions-of-internet-things-are-secured-by-the-same-private-keys/

How Many Certificates Do You Have?

Purchased?

Self-Signed?

Wildcard?

Functions?

If your company name is on the certificate, it’s an asset worth tracking!

Certificates As Assets

Track as an asset category or use a vendor product

Monitor expiration and renewal dates

Know certificate function

How are you handling revoked certificates?

Choose a reliable CA

Self-signed Policies for generation and use

Clear process that is auditable

Certificates on the Web

All public pages present a verifiable EV certificate from a reputable CA

Use secure cookie flag

Don’t mix secure/non-secure content

Avoid redirect from http to https

Use wildcard certificates carefully

Review your web server TLS protocols

Consider using HSTS

Pin it?

Wildcard Certificates

Wildcards enable sub-domains (*.yourorg.com) support.yourorg.com and purchasing.yourorg.com

Trust extends over many systems

Avoid using wildcards for Login/validation pages

Entering sensitive personal data

Ecommerce purchase/checkout

Certificate compromise means numerous pages are affected

http://news.softpedia.com/news/PayPal-Phishing-Page-Hosted-on-Secure-Website-of-Malaysian-Police-Portal-359166.shtml

http://httpd.apache.org/docs/2.0/ssl/ssl_howto.html

HSTS – HTTPS Strict Transport Security

Helps mitigate SSL stripping

Reduces TLS downgrade attacks

Makes MITM harder

Protects cookie-based web login credentials

First connection can be leveraged

https://tools.ietf.org/html/rfc6797

Certificate Pinning

Using a set of info (often a hash), to double check certificate validity

Protects against CA compromise

Can be used to limit browser warnings

Can be used to find nation/state MITM activity

Helps with users who will just click on “Proceed” no matter what.

Administrative PITA

https://www.owasp.org/index.php/Pinning_Cheat_Sheet

Certificates Beyond the Browser

http://researchcenter.paloaltonetworks.com/2015/08/keyraider-ios-malware-steals-over-225000-apple-accounts-to-create-free-app-utopia/

If You Sign Code

Policy Awareness

Don’t share or reuse private keys

Customize firmware keys and use once

Time stamping

Library code

Signed code attests Where the code came from

That it has not been altered

Embedded devices

Reset default passwords

Limit remote administration

Regenerate crypto keys if possible Limits poor quality “default” keys

Know the exposure Scan your network

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20150625-ironporthttp://www.theregister.co.uk/2015/08/24/smart_fridge_security_fubar/

Monitor for Malware that Steals Certificates

Backdoor.Beasty, Infostealer.Snifula

Downloader.Parshell, Trojan.Spyeye, W32.Cridex, W32.Qakbot, Infostealer.Shiz, Trojan.Carberp, Trojan.Zbot

Mitigation Review

Treat certificates as assets

Review certificate stores in deployed systems (CNNIC)

Establish clear web policies and standards for PKI management

Establish clear code-signing policies and standards

Be aware of certificate issues in embedded systems

Track certificate-related events – internal and external

Have a plan for certificate loss or root revocation

Monitor for malware known to steal certificates

It’s not all about key lengths and algorithms – many process issues

After Today’s Talk

Government in the Middle http://www.slate.com/blogs/future_tense/2015/12/14/kazakhstan_wants_citizens_to_download_a_mandatory_nat

ional_security_certificate.html

Perspectives from C-M http://perspectives-project.org/

Sovereign Keys from EFF https://www.eff.org/deeplinks/2011/11/sovereign-keys-proposal-make-https-and-email-more-secure

DNSSEC in conjunction with SSL - HSTS