CVE-2019-18800

high

Description

Viber through 11.7.0.5 allows a remote attacker who can capture a victim's internet traffic to steal their Viber account, because not all Viber protocol traffic is encrypted. TCP data packet 9 on port 4244 from the victim's device contains cleartext information such as the device model and OS version, IMSI, and 20 bytes of udid in a binary format, which is located at offset 0x14 of this packet. Then, the attacker installs Viber on his device, initiates the registration process for any phone number, but doesn't enter a pin from SMS. Instead, he closes Viber. Next, the attacker rewrites his udid with the victim's udid, modifying the viber_udid file, which is located in the Viber preferences folder. (The udid is stored in a hexadecimal format.) Finally, the attacker starts Viber again and enters the pin from SMS.

References

https://thesamarkand.tumblr.com/post/188785277609/viber-messenger-remote-account-reset-0day

Details

Source: Mitre, NVD

Published: 2019-11-06

Updated: 2026-06-17

Risk Information

CVSS v2

Base Score: 4.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:N/A:N

Severity: Medium

CVSS v3

Base Score: 8.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Severity: High

EPSS

EPSS: 0.00234