Zero-day vulnerability in Telegram Desktop for Windows

Spoofing attack

According to Kaspersky Lab, this vulnerability was exploited in the wild since March 2017 until October 2017. The attackers used the vulnerability to install cryptocurrency miners on victimsтАЩ computers.

Vulnerability details

Advisory: SB2018021305 - Spoofing attack in Telegram Desktop for Windows

Vulnerable component: Telegram Desktop for Windows


CVSSv3 score: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:L/E:H/RL:O/RC:C

CWE-ID: CWE-451 - User Interface (UI) Misrepresentation of Critical Information (Clickjacking, spoofing)


The vulnerability allows a remote attacker to perform spoofing attack.

The vulnerability exists due to improper parsing of right-to-left override (RLO) character when processing names of the transmitted files in Telegram Desktop for Windows. A remote attacker can create a specially crafted filename with malicious content (e.g. a JavaScript file), disguise it as an image and trick the victim into opening it.

Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.

Note: this vulnerability has been exploited in the wild since March until October in 2017, according to Kaspersky Lab and was silently fixed by the vendor.