How do you feel about background game updates?
Chapter 1

The VIP list vs the bouncer's ban list

Chapter 2

The great Blizzard DNS rebinding bypass

Chapter 3

When video players go rogue

Chapter 4

The whitelist in your daily digital life

YOUR GOAL

Master of Securing the world with the whitelist fix

Ch 2 · The great Blizzard DNS rebinding bypass
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007skaty The host header whitelist defense in Blizzard's Update Agent

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007skaty Host Header Whitelisting

We match the incoming domains to our whitelist to block the fake requests.

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It is safer to define what is allowed than to try to ban every threat.

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007skaty Blizzard failed to fix a major software bug using a blacklist

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The local update agent loophole

007skaty The Blizzard Update Agent listened for commands on a local port without verification, allowing any visited website to hijack the program.

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The magic of DNS rebinding

007skaty The whitelist fix prevents unauthorized domains from sending commands to local applications

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The Whitelist Slide
BETA

007skaty Slide trusted apps onto the approved list to learn how whitelisting protects your network.

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Fun Fact

DNS rebinding speed: A DNS rebinding attack can hijack a local app in less than three seconds once a user visits a malicious page.

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Glossary
dns rebinding (noun)
A cyberattack that manipulates DNS resolution to bypass a web browser's same-origin policy. In 2018, Google researcher Tavis Ormandy demonstrated how this exploit could compromise the Blizzard Update Agent.

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Gossip

How do you feel about background game updates?

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Quiz

What was the main security issue with the Blizzard Update Agent discovered in 2018?

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007skaty The mechanics of a DNS rebinding exploit

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Quiz

Who was the Google Project Zero security researcher who discovered the Blizzard Update Agent vulnerability?

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007skaty The security loophole in the Blizzard Update Agent

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Quiz

How does DNS rebinding bypass a browser's Same-Origin Policy?

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Quiz

What IP address does a DNS rebinding attack target to reach a victim's local machine?

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Quiz

Why did security researcher Tavis Ormandy criticize Blizzard's initial patch for the DNS rebinding bug?

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Quiz

What did Blizzard's initial, flawed patch check to determine if a request was safe?

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Quiz

Which version of the Blizzard Update Agent finally introduced the robust host header whitelist fix?

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Quiz

What specific HTTP header does the final Blizzard fix validate to prevent DNS rebinding?

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