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. Serverless Security
defense against the
dark arts

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

4. We’re hiring! Visit
engineering.dazn.com
to learn more.
follow @dazneng for
updates about the
engineering team

5. follow @dazneng for
updates about the
engineering team
We’re hiring! Visit
engineering.dazn.com
to learn more.
WE’RE HIRING!

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. use prepared statements

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

25. security is as much about what your function
should do as well as what it shouldn’t do
(protect against data exfiltration)

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

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

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

31. your dependencies

32. your dependencies
transient dependencies

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

35. https://snyk.io

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

37. your security is as strong
as its weakest link

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
runs on
needs
Source Code
has
maintains

39. 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

42. 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, …

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

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
phishing…
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. 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

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

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

50. 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.

51. 20% of all monthly NPM downloads…

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

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

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

59. WTF!?!?

64. oh god, that was too easy…

67. compromised package is a
transient dependency
sigh…

68. still “works”…

71. npmjs.com/~hacktask

73. rm -rf /!!!

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

76. 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

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

79. use `npm ci` in CI environment

80. not specific to Node.js or NPM

81. the attackers are in…

82. the attackers are in…
what now?

83. Shared Responsibility Model

84. who can invoke the function?

85. what can the function access?

86. Least Privilege Principle

88. everything here
is trusted

90. sensitive data

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

92. always public
access is controlled via IAM

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

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

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

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

100. implement authentication
for internal APIs

102. use AWS_IAM
authentication for
internal APIs

104. minimise function’s access

108. requires developer discipline

111. 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

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

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

114. leverage server-side encryption

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

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

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

118. https://amzn.to/2DaXFwA

119. Least Privilege Principle

120. Disposability is a virtue

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

122. easier said than done…

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

124. identifying ownership of
individual functions is
much harder

125. tag every function with Team name

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

127. more likely to scale through
DoS attacks

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

129. configure WAF rules on
API Gateway and CloudFront

130. enable throttling

132. 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.

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

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

135. DoS attack
2+ Retries+
?

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

138. avoid (unnecessary) long timeouts

139. alert on error count

140. Day 1

141. Day 2

143. no long-lived compromised servers

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

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

149. no accidentally exposed directories

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

154. monitor activities in
unused regions using
CloudWatch Events

156. set up billing alarms in unused regions

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

158. Michael Nygard

159. least privilege principle

160. per function policies

161. account level isolation

162. Recap

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

165. sanitise inputs and outputs

166. Least Privilege Principle

167. here’s your per function policy
NEXT!

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

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

170. delete unused functions.

171. DoS DoW*
* Denial of Wallet

175. 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

176. don’t be an unwilling bit miner

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

178. prod dev
compartmentalise breaches

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

180. @theburningmonk
theburningmonk.com
github.com/theburningmonk