Linux user namespaces might not be secure enough? a.k.a. subverting POSIX capabilities

Erica Windisch
Nov 3, 2015 · 5 min read

Introducing Capabilities

“It questions why anyone would not use this feature.”

“You should always drop capabilities in your application, or before running your application. Container managers do this by default.”

Introducing User Namespaces

“When a user namespace is created, the SYS_CAP_ADMIN capability is added.”

“Linux capabilities may be completely subverted.”

Subverting Capabilities

User Namespaces: to the rescue! or not!

Is this is a vulnerability?

Erica Windisch

Written by

CTO and founder of IOpipe, Inc. working on Application Operations tools for serverless applications.

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