Sign up for our weekly newsletter!
REGISTER NOW |
||
|
||
Don't Call AWS' CloudFront Hijacking Problem a Vulnerability![]() Larry Loeb, Author, 4/6/2018
Amazon Web Services is trying rather hard to get its security game going to the next level. But security researchers keep finding new ways to mess with it. The newest one is from MindPoint Group, and involves the AWS CloudFront CDN service. Security analyst Matt Westfall found out that in a misconfigured CloudFront account, subdomains of legitimate sites could be hijacked. This is, at root, a flaw in CloudFront. While each CloudFront distribution will have a unique endpoint for users to point their DNS records to, all of the domains using a specific distribution must be listed in the "Alternate Domain Names" (CNAMEs) field in the options for that distribution.
![]() (Source: Security Now)
However, when the CDN gets a request, it uses the HOST header of the request to determine which distribution to use. In this scenario, if the HOST header does not match an entry in the "Alternate Domain Names" (CNAMEs) field of the intended distribution, the request will fail. Any other distribution that contains the specific domain in the HOST header will receive the request and respond to it normally. This is the mechanism that enables the hijack to occur. The binding mechanism that should be in place inside CloudFront is then easily bypassed. A request to one specific CloudFront subdomain will not be limited to only that associated distribution list. In his blog, Westfall wrote about how he tested out his observation. What Westfall ended up doing is creating a Python script that would test for misconfiguration and repoint vulnerable subdomains to the target of his choice. In his test, he ran the script for a few days and found that he had hijacked a lot of high-profile subdomains. They included two distinct US Federal "dot gov" organizations, Bloomberg Businessweek, Commonwealth Bank of Australia, Dow Jones, Harvard University, Red Cross and Reuters. The problem seemed to be widespread. The AWS response was interesting. Westfall discussed what he found out with the AWS Security team and the CloudFront engineers. As he put it, "...while they accept that the nuances of CloudFront's routing mechanism leave room for improvement, at no time have they decided to treat this issue as a vulnerability."
Huh. Westfall recommends that "most AWS customers with a single distribution can protect themselves by adding a wildcard domain (such as *.disloops.com) to the "Alternate Domain Names" (CNAMEs) field. Amazon isn't totally ignoring this, either. The CloudFront console now displays a popup when a user removes a CNAME from a CloudFront distribution that warns them to keep their DNS records in sync with their CloudFront distribution. Such a synchronization would prevent the possibility of hijacking. Amazon has been getting more security conscious lately. At the AWS Summit this week, the cloud provider introduced new automation tools for making secure apps easier to run in AWS. (See AWS Expands Cloud Security Automation.) Although the company doesn't consider the CloudFront situation a vulnerability, its engineers are trying to help users avoid the situation where it could happen. They seem to have realized that just the selling of runtime on someone else's computer may not be the entire business model that is needed for success. Related posts:
— Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek. |
Attackers have already begun to breach security at the BIOS level, according to a new report on BIOS security from Forrester Consulting.
The Sophos Managed Threat Response team found out that, where the Snatch ransomware is concerned, things just more ugly.
The Federal Bureau of Investigation's office in Portland, Ore., uses 'Tech Tuesday' to offer IoT security advice.
One of the most prevalent threats to the financial sector, the Dridex Trojan, was the subject of a recent alert.
Aviatrix, an enterprise VPN company with customers that include NASA, Shell and BT, has recently dealt with a vulnerability that was uncovered by Immersive Labs researcher and content engineer Alex Seymour.
Information Resources
upcoming Webinars
ARCHIVED
Top Tips for Blocking pwned [email protected]$$wOrds in Your Organization
Tuesday, October 29, 2019
12 p.m. New York/ 4:00 p.m. London Podcasts
Podcast: Infrastructure Hunting – Stopping Bad Actors in Their Tracks
Being able to effectively build a threat intelligence ecosystem or threat-hunting identification response requires both user and systems sophistication and capabilities. Security, orchestration, automation and response (SOAR) is a new technology designed to provide organizations a single comprehensive platform they can use to implement an intelligence driven security strategy.
Podcast: Digital Transformation, SD-WAN & Optimal Security
Dan Reis chats to Cybera's Josh Flynn about how to achieve digital transformation without sacrificing security. ![]() like us on facebook
|
|
![]() |
||
![]() |
Security Now
About Us
Contact Us
Help
Register
Events
Supporting Partners
Twitter
Facebook
RSS
Copyright © 2019 Light Reading, part of Informa Tech, a division of Informa PLC. All rights reserved. Privacy Policy | Cookie Policy | Terms of Use in partnership with
|