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SSL/TLS Trends, Practices, and Futures Brian A. McHenry, Security Solutions Architect [email protected] @bamchenry
© F5 Networks, Inc. 2
1. Global SSL Encryption Trends and Drivers
2. A Few “Best” Practices
3. Solutions
4. What’s Next?
Agenda
© F5 Networks, Inc. 3
• Worldwide spending on information security will reach $71.1 billion in 2014
• Data loss prevention segment recording the fastest growth at 18.9 percent,
• By 2015, roughly 10% of overall IT security enterprise product capabilities will be delivered in the cloud
• Regulatory pressure will increase in Western Europe and Asia/Pacific from 2014
Gartner Says Worldwide Information Security Spending Will Grow Almost 8 Percent in 2014
© F5 Networks, Inc. 4
IoE E-Commerce Privacy Mobility
Snowden
Trajectory and Growth of Encryption
Customer Trends:
• PFS/ECC Demanded
• SSL Labs Application Scoring
Emerging Standards:
• TLS 1.3, HTTP 2.0/SPDY
• RSA -> ECC
Thought Leaders and Influence:
• Google: SHA2, SPDY, Search Ranking by Encryption
• Microsoft: PFS Mandated
MARKET AMPLIFIERS
SSL growing ~30% annually. Entering the Fifth wave of transition (IoE)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
1998 2002 2006 2010 2014 Source: Netcraft
Mill
ions
of C
ertif
icat
es (C
A)
Years
© F5 Networks, Inc. 5
Timeline of SSL Vulnerabilities & Attacks
February 2010
September 2011
February 2013
March 2013
March 2013 … April
2014
RC4 Attacks Weakness in CBC cipher making plaintext guessing possible
BEAST & CRIME Client-side or MITB attacks leveraging a chosen-plaintext flaw in TLS 1.0 and TLS compression flaws
RFC 5746 TLS extension for secure renegotiation quickly mainstreamed
Lucky 13 Another timing attack.
August 2009
August 2009 Insecure renegotiation vulnerability exposes all SSL stacks to DoS attack
TIME A refinement and variation of CRIME
Heartbleed The end of the Internet as we know it!
© F5 Networks, Inc. 6
SSL Intelligence and Visibility (Full Proxy)
Enterprise key & Certificate Management
Advance HSM Support: • Highest Performing HSM
options • Virtualized low-bandwidth
options • Market Leading HSM
Vendor Support
Market Leading Encryption: • Optimized SSL in
Hardware and Software • Cipher Diversity (RSA,
ECC, DSA) • SSL Visibility: Proxy SSL
& Forward Proxy • SSL Traffic Intelligence:
• HSTS, HTTP 2.0/SPDY, OCSP Stapling, TLS Server Session Ticket
Fully Automated Key and Certificate Management: • For all BIG-IP platforms • For all vendor platforms • 3rd Party Integration for
best-in-class key encryption: Venafi, Symantec/ VeriSign
• PKI Supported Environments
The Three Pillars of SSL Everywhere
Hardware Security Modules
© F5 Networks, Inc. 7
Data Protection: Microsoft and Google Expands Encryption
© F5 Networks, Inc. 8
Not all curves are considered equal Different Authorities: • US NIST (US National Institute of Standards)
with 186-2 (recently superseded in 2009 by the new186-3) • US ANSI (American National Standard Institute) with X9.62 • US NSA (National Security Agency)
Suite-B Cryptography for TOP SECRET information exchange • International SACG (Standards for efficient cryptography
group) with Recommended Elliptic Curve Domain Parameters • German ECC Brainpool withECC Brainpool with their
Strict Security Requirements • ECC Interoperability Forum composed by Certicom, Microsoft,
Redhat, Sun, NSA
If You Thought Encryption was confusing… ECC, PFS and Curves
© F5 Networks, Inc. 9
Not all curves are considered equal Different Names: • Secp256r1, Prime256v1, NIST
P-256 Different Kinds of Curves: • ECC over Prime Field (Elliptic
Curve) • ECC over Binary Field (Koblitz
Curve) Other Curves: • Curve25519 (Google) • Mumford (Microsoft) • Brainpool
If You Thought Encryption was confusing… ECC, PFS and Curves
Some SSL Best Practices
© F5 Networks, Inc. 11
• Google has begun adjusting page rank based on SSL implementations
• F5 customers have third-party/B2B requirements for strong encryption
• SSL Labs’ Pulse tool has made testing easy
• Users and businesses are choosing services based on Pulse grades
SSL: Not Just for Security
© F5 Networks, Inc. 12
• Set the option for Secure Renegotiation to “Require”
• Disable SSLv2 and SSLv3 (DEFAULT in 11.5+)
• Use an explicit, strong cipher string, such as: • NATIVE:!SSLv2:!EXPORT:ECDHE+AES-GCM:ECDHE+AES:ECDHE
+3DES:DHE+AES-GCM:DHE+AES:DHE+3DES:RSA+AES-GCM:RSA+AES:RSA+3DES:-MD5:-SSLv3:-RC4
• Prefer Perfect Forward Secrecy (PFS) • Done via prioritizing Ephemeral (DHE, ECDHE) ciphers in the string above
• Enable TLS_FALLBACK_SCSV extension
• Enable HTTP Strict Transport Security (HSTS) • iRule in pre-Badger versions of TMOS • Integrated into HTTP profile in next release
Achieving A+ Grades on SSLLabs.com
© F5 Networks, Inc. 13
HTTP Strict Transport Security iRule
when HTTP_RESPONSE {
HTTP::header insert Strict-Transport-Security "max-age=[expr {$static::expires - [clock seconds]}]; includeSubDomains”
}
© F5 Networks, Inc. 14
© F5 Networks, Inc. 15
If I sound smart about crypto…
© F5 Networks, Inc. 16
SSL Feature Availability
Feature TMOS TLS 1.2 10.2.3 ECC 11.5.0 PFS 11.4.0 SHA256 (SHA2) 10.2.3 SPDY 11.2.0 HTTP 2.0* 11.6.0 HSTS iRules/12.0
Feature TMOS Secure Renegotiation (RFC 5746)
10.2.3
TLS_FALLBACK_SCSV 11.5.0
Network HSM 11.2.1
Onboard HSM Y
SNI 11.1.0
Hybrid Certificates (ECC & RSA)*
11.5.0
A Peek Under the Hood
© F5 Networks, Inc. 18
Network
Session
Application
Web application
Physical
Client / Server
L4 Firewall: Full stateful policy enforcement and TCP DDoS mitigation
SSL inspection and SSL DDoS mitigation
HTTP proxy, HTTP DDoS and application security
Application health monitoring and performance anomaly detection
Network
Session
Application
Web application
Physical
Client / Server
Full Proxy Security
Proxy SSL (Visibility)
ASM
SSL Forward Proxy (Visibility)
SWG
© F5 Networks, Inc. 19
PFS, ECC and SSL Visibility Supported Key Exchange Un-Supported
Key Exchange SSL Offload (Classic)
Full Support None
SSL Forward Proxy
Client Side RSA ECDHE-RSA EDH-RSA
Server Side Full Support
ECDHE-ECDSA ECDH-ECDSA EDHE-DSS
Proxy SSL (Split/Passive SSL)
RSA ECDHE-RSA ECDH-ECDSA ECDH-ECDSA EDH-RSA DHE-DSS
© F5 Networks, Inc. 20
Proxy Chain
HUD chains are a series of filters which implement the configuration. The HUD chain is divided into two halves, client and server side. Filters on HUD chains usually are arranged as client/server pairs. The two halves are joined by the “proxy”.
Data Center
BIG-IP Platform
Clients
T C P
S S L
H T T P
P R O X Y
H T T P
S S L
T C P
• App “point of delivery & definition”
• App Intelligence - layer 3- 7 visibility
• Distinct client / server control
• Unified services / context
• Interoperability and gateway functions
Intelligent Full Proxy Benefits
BIG-IP Architecture – Proxy Chain
© F5 Networks, Inc. 21
Proxy Chain
Each SSL filter handles connection to device on their side of the proxy. Normally, the two SSL filters operate completely independently. Between the two filters, all data is available unencrypted. To fully offload the backend server, remove the server side SSL filter.
Data Center
BIG-IP Platform
Clients
T C P
S S L
H T T P
P R O X Y
H T T P
S S L
T C P
• App “point of delivery & definition”
• App Intelligence - layer 3- 7 visibility
• Distinct client / server control
• Unified services / context
• Interoperability and gateway functions
Intelligent Full Proxy Benefits
BIG-IP Architecture – SSL Termination
© F5 Networks, Inc. 22
Data Center
Proxy Chain
Proxy SSL allows the client certificate to be presented to the server. Intermediary filters are disabled. SSL filters operate in monitor mode during the handshake. Post-handshake, SSL enables decryption and other filters.
BIG-IP Platform
Clients
T C P
S S L
H T T P
P R O X Y
H T T P
S S L
T C P
• Allows server to perform client cert auth • L7 content inspection after handshake • Certificate transparent to end user
Intelligent Full Proxy Benefits
BIG-IP Architecture – Proxy SSL
© F5 Networks, Inc. 23
Proxy Chain
Forward SSL is used in Forward Proxy deployments. “Just in time” certificate creation is used to decrypt SSL connections. Enables policy based inspection of secure content. Requires the ability to create trusted certificates to work.
Data Center
BIG-IP Platform
Clients
T C P
S S L
H T T P
P R O X Y
H T T P
S S L
T C P
• Inspect secure traffic at network edge • Transparent to the end user • Policy based bypass by:
• Source IP Address • Destination IP Address • Host Name (SAN,CN,SNI)
Forward SSL Proxy Benefits
BIG-IP Architecture – Forward SSL
What’s Next?
© F5 Networks, Inc. 25
• RFC 6797
• HSTS is enabled by the “Strict-Transport-Security” HTTP header e.g.: Strict-Transport-Security: max-age=10886400; includeSubDomains; preload
• When received, browsers will: • Automatically convert HTTP references to HTTPS references • Disallow certificate exemptions (self-signed, etc.) • Cache HSTS information and reuse stored values for new sessions
New Feature: HTTP Strict Transport Security
AVAILABLE IN 12.0
© F5 Networks, Inc. 26
HTTP Strict Transport Security Configuration
HTTP Profile Screen
© F5 Networks, Inc. 27
A Quick Primer on Certificate Revocation • If a SSL certificate is stolen or compromised, sites need a way to revoke the
certificate so it will no longer be trusted. Revocation is handled by either CRL or OCSP.
• CRL: Certificate Revocation List • The browser retrieves the list of all revoked certificates from the CA. • The browser then parses the whole list looking for the certificate in question.
• OCSP: Online Certificate Status Protocol • The browser sends the certificate to the CA for validation. • The CA responds that the certificate is good, revoked, or unknown.
• OCSP is more efficient than CRL, but there’s room for improvement!
New Feature: OCSP Stapling
AVAILABLE IN 11.6
© F5 Networks, Inc. 28
• OCSP and CRL checks add significant overhead: • DNS (1334ms) • TCP handshake (240ms) • SSL handshake (376ms) • Follow certificate chain (1011ms) • DNS to CA (300ms) • TCP to CA (407ms) • OCSP to CA #1 (598ms) • TCP to CA #2 (317ms) • OCSP to CA #2 (444ms) • Finish SSL handshake (1270ms) < T O TA L : 6 . 3 S e c o n d s >
• Add up the time for each step and you'll see that over 30% of the SSL overhead comes from checking whether the certificate has been revoked.
• These checks are serial and block downloads.
OCSP & CRL Checks Hurt Performance
This portion is revocation check overhead.
© F5 Networks, Inc. 29
• OCSP Stapling allows the server to attach CA signed information regarding the certificates validity.
• Processing with OCSP enabled: • DNS (1334ms) • TCP handshake (240ms) • SSL handshake (376ms) • Follow certificate chain (1011ms) • Process OCSP Data (10ms) • Finish SSL handshake (1270ms) < T O TA L : 4 . 2 S e c o n d s > O C S P S t a p l i n g a l s o e l i m i n a t e s c o m m u n i c a t i o n w i t h a t h i r d p a r t y d u r i n g c e r t i f i c a t e v a l i d a t i o n . T h i s m a y b e c o n s i d e r e d b e t t e r s e c u r i t y s i n c e i t p r e v e n t s i n f o r m a t i o n l e a k a g e .
OCSP Stapling to the Rescue
© F5 Networks, Inc. 30
OCSP Stapling Configuration
Profile Location Assignment to Client SSL Profile
© F5 Networks, Inc. 31
OCSP Stapling Configuration
Changes to ‘Proxy Pool’ when ‘Use Proxy Server’ is enabled
© F5 Networks, Inc. 32
• SSL termination and inspection from BIG-IP® Local Traffic Manager™ (LTM)
• Hybrid cipher support for ECC and RSA ciphers
• SSL crypto-offload for additional SSL capacity
• Integration with network HSMs from SafeNet and Thales for key management
SSL Everywhere RA – Bringing it all Together
© F5 Networks, Inc. 33
SSL Everywhere