1. Real World Cloud
Application Security
Lessons Learned Running Large Scale Systems
in the Public Cloud
Jason Chan - chan@netflix.com

2. Netflix, Inc.
“With more than 27 million
streaming members in the
United States, Canada, Latin
America, the United Kingdom
and Ireland, Netflix, Inc. is the
world's leading internet
subscription service for enjoying
movies and TV programs . . .”
Source: http://ir.netflix.com

3. Me
• Cloud Security Architect @ Netflix
• Responsible for:
• Cloud app, product, infrastructure, ops
security
• Previously:
• Led security team @ VMware
• Earlier, primarily security consulting at
@stake, iSEC Partners

4. AppSec Challenges

5. AppSec Challenges

6. Lots of Good Advice
• BSIMM
• Microsoft SDL
• SAFECode

7. But, what works?
Forrester Consulting, 12/10

8. Especially, given phenomena
such as DevOps, cloud, agile,
and the unique characteristics
of an organization?

9. Netflix Engineering
Characteristics

10. Netflix in the Cloud -
Why?

11. Netflix in the Cloud -
Why?

12. Netflix in the Cloud -
Why?
“Undifferentiated heavy lifting”

13. Netflix in the Cloud -
Why?
“Undifferentiated heavy lifting”

14. Netflix in the Cloud -
Why?
“Undifferentiated heavy lifting”

15. Netflix is now ~99% in
Public Cloud

16. On the way to the
cloud . . .

17. On the way to the
cloud . . .
(or NoOps,
depending on definitions)

18. Some As-Is #s
• 27m+ subscribers
• 10,000s of systems
• 100s of engineers, apps
• ~250 test deployments/day *
• ~70 production deployments/day *
* Sample based on this week’s activities

19. Deploying Code @ Netflix

20. A common graph @ Netflix

21. A common graph @ Netflix
Lots of watching in prime time

22. A common graph @ Netflix
Lots of watching in prime time Not as much in early morning

23. A common graph @ Netflix
Lots of watching in prime time Not as much in early morning
Old way - pay and provision for peak, 24/7/365

24. A common graph @ Netflix
Lots of watching in prime time Not as much in early morning
Old way - pay and provision for peak, 24/7/365
Multiply this pattern across the dozens of apps
that comprise the Netflix streaming service

25. Solution: Load-Based
Autoscaling

26. Autoscaling

27. Autoscaling
• Goals:

28. Autoscaling
• Goals:
• # of systems matches
load requirements

29. Autoscaling
• Goals:
• # of systems matches
load requirements
• Load per server is
constant

30. Autoscaling
• Goals:
• # of systems matches
load requirements
• Load per server is
constant
• Happens without
intervention (the
‘auto’ in autoscaling

31. Autoscaling
• Goals: • Results:
• # of systems matches
load requirements
• Load per server is
constant
• Happens without
intervention (the
‘auto’ in autoscaling

32. Autoscaling
• Goals: • Results:
• # of systems matches • Continuously
load requirements adding/removing
nodes
• Load per server is
constant
• Happens without
intervention (the
‘auto’ in autoscaling

33. Autoscaling
• Goals: • Results:
• # of systems matches • Continuously
load requirements adding/removing
nodes
• Load per server is
constant • New nodes must
mirror existing
• Happens without
intervention (the
‘auto’ in autoscaling

34. Every change requires a new
cluster push
(not an incremental change to
existing systems)

35. Deploying must be easy
(it is)

36. Netflix Deployment
Pipeline

37. Netflix Deployment
Pipeline
Perforce/Git
Code change
Config change

38. Netflix Deployment
Pipeline
RPM file with
app-specific
bits
YUM
Perforce/Git
Code change
Config change

39. Netflix Deployment
Pipeline
RPM file with
app-specific
bits
YUM
Perforce/Git Bakery
Code change Base image +
Config change RPM

40. Netflix Deployment
Pipeline
RPM file with VM template
app-specific ready to launch
bits
YUM AMI
Perforce/Git Bakery
Code change Base image +
Config change RPM

41. Netflix Deployment
Pipeline
RPM file with VM template
app-specific ready to launch
bits
YUM AMI
Perforce/Git Bakery ASG
Code change Base image + Cluster config
Config change RPM Running systems

42. Netflix Deployment
Pipeline
RPM file with VM template
app-specific ready to launch
bits
YUM AMI
Perforce/Git Bakery ASG
Code change Base image + Cluster config
Config change RPM Running systems

43. Operational Impact
• No changes to running systems
• No systems management infrastructure
• Fewer logins to prod
• No snowflakes
• Trivial “rollback”

44. Security Impact
• Need to think differently on:
• Vulnerability management
• Patch management
• User activity monitoring
• File integrity monitoring
• Forensic investigations

45. Org, architecture,
deployment is different,
what about security?

46. We’ve adapted too.
Some principles we’ve
found useful.

47. Integrate

48. Base AMI Security
• AMI = Amazon Machine • Average age of running
Image instance: 24 days*
• @ Netflix, all apps are • 60% of instances less
based on “Base AMI”, than 1 week old*
and new pushes pick up
the latest
• Concentrating testing
and improvements here
provides greatest impact
* Based on one-time sampling (yesterday)

49. Base AMI Testing
• The base AMI is managed
like other packages, via
P4, Jenkins, etc.
• We watch the base AMI’s
SCM directory & kick
off testing when it
changes
• Launch an instance of
the AMI, perform vuln
scan and other checks

50. Base AMI Testing
• The base AMI is managed
like other packages, via
P4, Jenkins, etc.
• We watch the base AMI’s
SCM directory & kick
off testing when it
changes
• Launch an instance of
the AMI, perform vuln
scan and other checks

51. Base AMI Testing
• The base AMI is managed
like other packages, via
P4, Jenkins, etc.
• We watch the base AMI’s
SCM directory & kick SCAN COMPLETED ALERT
off testing when it Site name: AMI1
changes Stopped by: N/A
Total Scan Time: 4 minutes 46 seconds
•
Critical Vulnerabilities: 5
Launch an instance of Severe Vulnerabilities: 4
Moderate Vulnerabilities: 4
the AMI, perform vuln
scan and other checks

52. Security Packaging
• All security tools use the same toolchain as
the rest of engineering (P4/Git, Jenkins, etc.)

53. • From the RPM spec file of a webserver:
Requires: ossec cloudpassage nflx-base-harden
hyperguard-enforcer

54. • Pulls in the following RPMs:
• Host hardening package
• WAF agent
• OSSEC (HIDS agent)
• CloudPassage (config assessment,
FW, etc.)

55. Static Analysis
• Available self-service through build
environment (FindBugs, PMD)
• Jenkins (CI) plugin to display graphs and
support drill through to results

57. MAN Integration

58. Many systems involved,
standardization is
important

59. Central Alerting
Gateway
• A single place to generate alerts
• Python, Java libraries (or json post) to easily
alert on events of interest
• Ties in to PagerDuty notification system
• Allows for stateful alerting and some
response
• A prerequisite that our tools will leverage

60. CAG Example
import CORE.Gateway
gw = CORE.Gateway.Gateway()
gw.send("testcluster", "normal", "Something went
wrong")

61. Chronos
• Timeline system (API and UI) with Java/
Python libraries, or json post
• Track config changes, deployments, etc.
• Security tools also leverage for tracking and
analysis

62. Chronos Security
Examples
• What IP addresses have been blacklisted by
the WAF in the last few weeks?
GET /api/v1/event?
timelines=type:blacklist&start=20121012000000000
• Which security groups have changed today?
GET /api/v1/event?
timelines=type:securitygroup&start=20121024000000000

63. Make the right way easy
(and secure)

64. Cryptex
• Many uses of crypto in web/distributed
systems:
• Encrypt/decrypt (cookies, data, etc.)
• Sign/verify (URLs, data, etc.)
• Known as an area where developers should
not DIY

65. • Multi-layer crypto system (HSM basis, scale
out layer)
• Easy for developers to use
• Key management handled transparently
• Access control and auditable operations
ICipherContext cipherContext =
CryptexClientFactory.getCipherContext(KeySet.testkey);
// encryption
String cipherText = cipherContext.encrypt("NETFLIX");
// decryption
String plainText = cipherContext.decrypt(cipherText);

66. Cloud SSO
• Authenticated access to dashboards, admin
apps in the cloud is problematic
• No datacenter access, no LDAP, AD

67. Cloud SSO
• Solution - leverage OneLogin SaaS SSO
option (SAML) used by IT for enterprise
apps
• Built filter that integrates with our platform
web server to make SSO/authentication
trivial

68. Trust, but verify

69. Culture of ‘freedom and
responsibility’ precludes
traditional centralized,
command and control approach

70. Security Monkey
• Cloud APIs make • Includes:
verification and analysis
of configuration &
running state simpler
• Cert checking
• Firewall analysis
• Security Monkey created
as the framework for
this analysis
• IAM entity analysis
• Limit warnings

71. Security Monkey
From: Security Monkey
Date: Wed, 24 Oct 2012 17:08:18 +0000
To: Security Alerts
Subject: prod Changes Detected
Table of Contents:
Security Groups
Changed Security Group
<sgname> (eu-west-1 / prod)
<#Security Group/<sgname> (eu-west-1 / prod)>

72. Exploit Monkey
• Autoscaling group is unit of deployment, so
changes signal a good time to rerun
dynamic scans
On 10/23/12 12:35 PM, Exploit Monkey wrote:
I noticed that testapp-live has changed current ASG name from testapp-
live-v001 to testapp-live-v002.
I'm starting a vulnerability scan against test app from these private/
public IPs:
10.29.24.174

73. ELB Checker (gauntlt)
• AWS’ Elastic Load Balancer (ELB) provides cross-
datacenter traffic balancing, but no security
controls (if your cluster is attached to an ELB, it is
available to the Internet)
• Engineers may misunderstand use cases for ELBs,
security features, and/or other measures that can
be used to protect ELB-fronted clusters

74. Solution: gauntlt Testing
1. Launch gauntlt test runner
instance, loaded with “master
list” of ELBs and expected state
2. Determine “target list” of
current ELBs to evaluate
3. Generate per-ELB listener
gauntlt attack files
4. Execute attacks
5. Alert on failures and new ELBs
6. Triage findings and update ELB
master list

75. Self-service, with
exceptions

76. AWS Security Groups
• Asgard cloud orchestration
tool allows developers to
configure their own firewall
rules
• Limited to same-account
groups, no IP-based rules
• Handles 95% of
requirements, JIRAs for
additional changes, and
Security Monkey to keep an
eye on things

77. Takeaways
• Netflix runs a large, dynamic service in AWS
• Good guidance + specific context can help
jumpstart a pragmatic security program
• Newer concepts like cloud & DevOps need
updated approach to security
• Don’t swim upstream - integrate and
collaborate with your engineering partners

78. Netflix References
• http://netflix.github.com/
• http://techblog.netflix.com/
• http://slideshare.net/netflix

79. Other References
• http://www.webpronews.com/netflix-outage-angers-
customers-2008-08
• http://www.pcmag.com/article2/0,2817,2395372,00.asp
• http://www.readwriteweb.com/archives/
etech_amazon_cto_aws.php
• http://bsimm.com/online/
• http://www.microsoft.com/en-us/download/
confirmation.aspx?id=29884
• http://www.gauntlt.org

80. Questions?
chan@netflix.com