ResearchVulnerability in Bytello Share

Vulnerability in Bytello Share

Bytello Share is a software used to share the screen of a device. The vulnerability was found in the installation process of the software.

Local privilege escalation vulnerability in Bytello Share Installer

The installer uses a folder that is writeable by unprivileged users to store executables and DLLs. An attacker with access to the system can manipulate the files during the installation process to gain SYSTEM privileges.

Note that the installer needs administrative rights to run. However, we were able to exploit this in a scenario where all users were able to request the installation of the software using a web interface provided by the software deployment solution. In this case, the user can trigger the execution of the installer with elevated rights and then exploit the installation process to gain SYSTEM privileges.

The vulnerability was not acknowledged by the manufacturer and it is therefore unlikely that it will be fixed. Please refer to the Mitigation section on how to protect your environment.

CVSS-Score
6.7

Affected Version
Bytello Share 5.6.0.2497

Mitigation
We recommend refraining from using the Bytello Share Installer in scenarios where an unprivileged user can trigger the installation (e.g. using a Software Kiosk).

Credits
Kolja Grassmann <kolja.grassmann@cirosec.de>

Timeline
October 25, 2023: Vulnerability found
October 31, 2023: Manufacturer was contacted and informed about the vulnerability
November 6, 2023: Manufacturer informs us that they do not see an issue here, as administrative rights are required during the installation