Serious Bug Exposes Sensitive Data From Millions Sites Sitting Behind CloudFlare


A severe security vulnerability has been discovered in the CloudFlare content delivery network that has caused big-name websites to expose private session keys and other sensitive data.

CloudFlare, a content delivery network (CDN) and web security provider that helps optimize safety and performance of over 5.5 Million websites on the Internet, is warning its customers of the critical bug that could have exposed a range of sensitive information, including passwords, and cookies and tokens used to authenticate users.

Dubbed Cloudbleed, the nasty flaw is named after the Heartbleed bug that was discovered in 2014, but believed to be worse than Heartbleed.

The vulnerability is so severe that it not only affects websites on the CloudFlare network but affects mobile apps as well.

What exactly is “Cloudbleed,” how it works, how are you affected by this bug, and how you can protect yourself? Let’s figure it out.

What is Cloudbleed?

Discovered by Google Project Zero security researcher Tavis Ormandy over a week ago, Cloudbleed is a major flaw in the Cloudflare Internet infrastructure service that causes the leakage of private session keys and other sensitive information across websites hosted behind Cloudflare.

CloudFlare acts as a proxy between the user and web server, which caches content for websites that sits behind its global network and lowers the number of requests to the original host server by parsing content through Cloudflare’s edge servers for optimization and security.

Almost a week ago, Ormandy discovered a buffer overflow issue with Cloudflare’s edge servers that were running past the end of a buffer and were returning memory containing private data like HTTP cookies, authentication tokens, and HTTP POST bodies, with some of the leaked data already cached by search engines.

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