AWS has taken over the responsibilities of patching the OS and securing the underlying physical infrastructure that runs your serverless application, so what’s left for you to secure? Quite a bit it turns out. The OWASP top 10 is as relevant to you as ever; DOS attacks are still a threat even if you can probably brute force your way through it as AWS auto-scales Lambda functions automatically; and did you know attackers can easily steal your AWS credentials via your application dependencies? In addition to the traditional threats, serverless applications have more granular deployment units and therefore there are more things to configure and secure, and the tools and practices are still catching up with this fast changing world.

1. LONDON 18-19 OCT
2018
Security in the Serverless World
YAN CUI

2. Yan Cui
http://theburningmonk.com
@theburningmonk
Principal Engineer @

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6. AWS user since 2009

7. http://bit.ly/yubl-serverless

8. Shared Responsibility Model

9. Shared Responsibility Model

10. protection from OS attacks
Amazon automatically apply latest patches to host VMs

13. still have to patch your code
vulnerable code, 3rd party dependencies, etc.

15. https://snyk.io/blog/owasp-top-10-breaches

16. https://snyk.io/blog/owasp-top-10-breaches
Known Vulnerable Components cause 24% of the top 50 data breaches

17. https://snyk.io/blog/77-percent-of-sites-use-vulnerable-js-libraries

22. http://bit.ly/2topw5I

23. sanitise inputs & outputs
(standardise and encapsulate into shared lib)

25. http://bit.ly/2gSHtay
Broken Access Control
Insecure Direct Object Reference
Information Leakage
GraphQL Injection

26. http://bit.ly/2uKhGXF

27. http://bit.ly/2uKhGXF

29. app dependencies
is a
attack surface
BIGGER
than you think

30. your dependencies

31. your dependencies
transient dependencies

32. https://david-dm.org/request/request?view=tree

34. https://snyk.io

35. security updates are often
bundled with unrelated
feature and API changes

36. your security is as strong
as its weakest link

37. OS
Application
Dependencies
physical
infrastructure
NPM Authors
Container
runs in
runs in
runs in
has
hosted by published by
pushes to
Developers
develops uses
Users
guardsprotects
Networking
runs on
needs
Source Code
has
maintains

38. OS
Application
Dependencies
physical
infrastructure
NPM Authors
Container
runs in
runs in
runs in
has
hosted by published by
pushes to
Developers
develops uses
Users
guardsprotects
Networking
needs
runs on this is where an attacker will
target in a movie
Source Code
has
maintains

41. OS
Dependencies
physical
infrastructure
NPM Authors
Container
runs in
runs in
runs in
has
hosted by published by
pushes to
Developers
develops uses
Users
guardsprotects
Application
A9
Networking
runs on
needs
Source Code
has
maintains
A1, A3, …

42. people are often the WEAKEST link
in the security chain

44. OS
Dependencies
physical
infrastructure
NPM Authors
Container
runs in
runs in
runs in
has
hosted by published by
pushes to
Developers
develops uses
Users
guardsprotects
Application
phishing…
Networking
runs on
needs
Source Code
has
maintains

45. OS
Dependencies
physical
infrastructure
NPM Authors
Container
runs in
runs in
runs in
has
hosted by published by
pushes to
Developers
develops uses
Users
guardsprotects
Application
brute force, known
account leaks, …
Networking
runs on
needs
Source Code
has
maintains

46. OS
Dependencies
physical
infrastructure
NPM Authors
Container
runs in
runs in
runs in
has
hosted by published by
pushes to
Developers
develops uses
Users
guardsprotects
Application
brute force, known
account leaks, …
Networking
runs on
needs
Source Code
has
maintains

47. http://bit.ly/2sFDwYX
…obtained publish access to 14% of npm packages…

48. http://bit.ly/2sFDwYX
debug, request, react, co, express, moment, gulp, mongoose, mysql, bower,
browserify, electron, jasmine, cheerio, modernizr, redux, …

49. http://bit.ly/2sFDwYX
total downloads/month of the unique packages which I got
myself publish access to was 1 972 421 945, that’s
20% of the total number of d/m directly.

50. 20% of all monthly NPM downloads…

51. brute force
known account leaks from other sources
leaked NPM credentials (github, etc.)

52. http://bit.ly/2sFDwYX

53. http://bit.ly/2sFDwYX
662 users had password “123456”
172 — “123”
124 — “password”

56. WTF!?!?

61. oh god, that was too easy…

64. compromised package is a
transient dependency
sigh…

65. still “works”…

68. npmjs.com/~hacktask

70. rm -rf /!!!

71. NPM default - get latest
“compatible” version, ie. 1.X.X

72. clean install (eg. on CI server) will
download the latest, compromised
package without any code change…
NPM default - get latest
“compatible” version, ie. 1.X.X

74. use npm shrinkwrap
or upgrade to NPM 5 or above

75. not specific to Node.js or NPM

76. the attackers are in…

77. the attackers are in…
what now?

78. Shared Responsibility Model

79. who can invoke the function?

80. what can the function access?

81. Least Privilege Principle

83. everything here
is trusted

85. sensitive data

86. http://bit.ly/2zHvbcB

87. always public
access is controlled via IAM

92. http://bit.ly/2lNInES

93. adds up to 10s to cold start!!
http://bit.ly/2lNInES

94. compromised servers allow
attacker to access all of
your sensitive data!

95. implement authentication
for internal APIs

97. always public
implement authentication with
API keys, Cognito, or custom
authorizer functions

98. use AWS_IAM
authentication for
internal APIs

100. minimise function’s access

104. requires developer discipline

108. AWS Lambda
docs
Write your Lambda function
code in a stateless style, and
ensure there is no affinity
between your code and the
underlying compute
infrastructure.
http://amzn.to/2jzLmkb

109. S3
AWS IoT
DynamoDB
RDS
EventStore
Elasticsearch Couchbase
Redshift
Neo4j
Google BigQuery

110. secure sensitive data both
at rest and in-transit

111. leverage server-side encryption

112. http://amzn.to/1N3Twb8

113. http://amzn.to/1xF41eX

114. http://amzn.to/2tgvFR2

115. Least Privilege Principle

116. Disposability is a virtue

117. AWS Lambda
docs
Delete old Lambda functions that
you are no longer using.
http://amzn.to/2jzLmkb

118. easier said than done…

119. identifying component
ownership in a big IT
organization is challenging

120. identifying ownership of
individual functions is
much harder

121. source: http://www.digitalattackmap.com

122. more likely to scale through
DoS attacks

123. DoS + per exec billing =
Denial of Wallet problem

124. have to choose between a
DoS and a DoW problem…

126. AWS Shield Advanced also gives you access to the AWS DDoS
Response Team (DRT) and protection against DDoS related
spikes in your ELB, CloudFront or Route 53 charges.

127. async sync
S3
SNS
SES
CloudFormation
CloudWatch Logs
CloudWatch Events
Scheduled Events
CodeCommit
AWS Config
http://amzn.to/2vs2lIg
Cognito
Alexa
Lex
API Gateway
streams
DynamoDB Stream
Kinesis Stream
Lambda handles retries
(twice, then DLQ)

128. http://bit.ly/2v7F2E4

129. DoS attack
2+ Retries+
?

130. DoS attack
Regex DoS attack
long Lambda timeout
2+ Retries+
?

132. Day 1

133. Day 2

135. no long-lived compromised servers

136. containers are reused, avoid
sensitive data in /tmp

137. https://www.puresec.io/function-shield

141. no accidentally exposed directories

145. http://bit.ly/2tlGTbc

146. monitor activities in
unused regions using
CloudWatch Events

148. set up billing alarms in unused regions

149. watertight compartments that can contain water in
the case of hull breach or other leaks

150. Michael Nygard

151. least privilege principle

152. per function policies

153. account level isolation

154. Recap

155. app dependencies
is a
attack surface
BIGGER
than you think

157. sanitise inputs and outputs

158. Least Privilege Principle

159. here’s your per function policy
NEXT!

160. S3
AWS IoT
DynamoDB
RDS
EventStore
Elasticsearch Couchbase
Redshift
Neo4j
Google BigQuery
encrypt data at rest

161. S3
AWS IoT
DynamoDB
RDS
EventStore
Elasticsearch Couchbase
Redshift
Neo4j
Google BigQuery
and in-transit

162. delete unused functions.

163. DoS DoW*
* Denial of Wallet

167. no server*
no OS attacks
no long lived compromised servers
* I know I know, there’s still a server somewhere, but it’s managed and secured by AWS engineers who can do a much better job of it
than most of us can; and the servers are ephemeral and short-lived

168. don’t be an unwilling bit miner

169. don’t be an unwilling bit miner
safeguard your credentials…

170. prod dev
compartmentalise breaches

171. people are often the WEAKEST link
in the security chain

172. LONDON 18-19 OCT
2018
[ Thank You!
@theburningmonk
theburningmonk.com ]