Avoid Impersonation And The Trustworthy Flag

Solomon Rutzky explains how you can use module signing to avoid the security risks which come with impersonation and setting Trustworthy on:

Admittedly, using Cross-Database Ownership Chaining and/or Impersonation and/or TRUSTWORTHY are quicker and easier to implement than Module Signing. However, the relative simplicity in understanding and implementing these options comes at a cost: the security of your system.

  • Cross-DB Ownership Chaining:
    • security risk (can spoof User / DB-level)
    • db_ddladmin & db_owner users can create objects for other owners
    • Users with CREATE DATABASE permission can create new databases and attach existing databases
  • Impersonation:
    • If IMPERSONATE permission is required:
      • can be used any time
      • No granular control over permissions
    • Cross-DB operations need TRUSTWORTHY ON
    • Need to use ORIGINAL_LOGIN() for Auditing
    • Elevated permissions last until process / sub-process ends or REVERT
  • TRUSTWORTHY:
    • Bigger security risk
      • can also spoof Logins, such as “sa” !
      • If using SQLCLR Assemblies, no per-Assembly control of ability to be marked as either EXTERNAL_ACCESS or UNSAFEall Assemblies are eligible to be marked as either of those elevated permission sets.

The common theme across all three areas is no control, within a Database, over who or what can make use of the feature / option, or when it can be used.

Read the whole thing.

Related Posts

Testing TDE Performance

Eduardo Pivaral tests the performance of a database with Transparent Data Encryption versus that same database without encryption: Transparent data encryption (TDE) helps you to secure your data at rest, this means the data files and related backups are encrypted, securing your data in case your media is stolen. This technology works by implementing real-time I/O […]

Read More

Security Improvements In Kafka And Confluent Platform

Vahid Fereydouny demonstrates a number of security improvements made to Apache Kafka 2.0 as well as Confluent Platform 5.0: Over the past several quarters, we have made major security enhancements to Confluent Platform, which have helped many of you safeguard your business-critical applications. With the latest release, we increased the robustness of our security feature […]

Read More

Categories

January 2018
MTWTFSS
« Dec Feb »
1234567
891011121314
15161718192021
22232425262728
293031