Spoofing attack in Telegram Desktop for Windows

Published: 2018-02-13
Risk Medium
Patch available YES
Number of vulnerabilities 1
Exploitation vector Network
Public exploit This vulnerability is being exploited in the wild.
Vulnerable software
Telegram Desktop for Windows
Client/Desktop applications / Messaging software

Vendor Telegram

Security Advisory

This security advisory describes one medium risk vulnerability.

1) Spoofing attack

Risk: Medium

CVSSv3: 5.6 [CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:L/E:H/RL:O/RC:C] [PCI]


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

Exploit availability: No


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.


Update to the latest version. The vulnerability was reported to vendor in October 2017 and fixed afterwards.
It is unclear, in which version this vulnerability was fixed, however according to Kaspersky Lab statement and commits to the official GitHub repository, version 1.1.23 should be vulnerable to this issue.

Vulnerable software versions

Telegram Desktop for Windows: 1.1.23

CPE External links


Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.