Telegram offering encrypted chats and phone calls over the internet but its desktop and windows version leaking IP address.
Telegram Desktop application allows users only making phone calls by setting the P2P connection which is available to change from “Settings > Privacy and security > Calls > peer-to-peer”
But tdesktop and telegram for windows don’t have any option like this to set up the Peer-to-peer connection.
Dhiraj Mishra, Researcher who discovered this serious flaw in Telegram stated that “Even telegram for Android will also leak your IP address if you have not set “Settings > Privacy and security > Calls > peer-to-peer >nobody” (But Peer-to-Peer settings for call option already exists in a telegram for android”
Telegram Desktop – IP Leaking Scenario
Below example that can demonstrate from Ubuntu Desktop Telegram console while users making phone calls from Telegram desktop.
1. Open tdesktop,
2. Initiate a call to anyone,
3. You will notice the end user IP address is leaking.
In this case, Telegram desktop clients forMac, Windows, and Linux also would reveal users’ IP addresses.
So making phone calls from the desktop version and windows would leaks both users IP addresses but the mobile version will not do the same since it was set as Peer-to-peer communication by default.
He Also Explains the other following scenario that indicates the part of leaking IP address of the following.
- Open tdesktop in Ubuntu and login with user A
- Open telegram in windows phone login with user B
- Let user B initiate the call to user A
- While user A access log will have the public/private IP address of user B.
After reporting this flaw to Telegram, Dhiraj was awarded a €2,000 bounty for his finding and issued the patch in the 1.3.17 beta and 1.4.0 versions of Telegram for Desktop where you can set your “P2P to Nobody/My Contacts.
Later CVE-2018-17780 was assigned to this vulnerability and the user requested to update their desktop clients as soon as possible in order to patch this flaw to maintain the anonymity.