CVE-2022-21695

MEDIUM4.3EPSS 0.28%

Improper Access Control in Onionshare

Published: 1/21/2022Modified: 10/8/2024
Also known as:GHSA-99p8-9p2c-49j4PYSEC-2022-46

Description

Between September 26, 2021 and October 8, 2021, [Radically Open Security](https://www.radicallyopensecurity.com/) conducted a penetration test of OnionShare 2.4, funded by the Open Technology Fund's [Red Team lab](https://www.opentech.fund/labs/red-team-lab/). This is an issue from that penetration test. - Vulnerability ID: OTF-009 - Vulnerability type: Improper Access Control - Threat level: Low ## Description: Authenticated users (or unauthenticated in public mode) can send messages without being visible in the list of chat participants. ## Technical description: Prerequisites: - Existing chatroom - Access to the chatroom (Public or known Private Key) - Either a modified frontend client or manual requests from burp/curl If a user opens the chatroom without emitting the join message he will not be present in session.users[x] list. Therefore there is no listing in the frontend and no chat participant knows another party joined the chat. It is still possible to send messages in the chatroom. If a user decides to abuse OTF-003 (page 22) he can impersonate messages from existing users; others would not be able to distinguish original and faked messages. This is also a prerequisite for OTF-004 (page 19). ## Impact: An adversary with access to the chat environment can send messages to the chat without being visible in the list of chat participants. ## Recommendation: - Allow chat access only after emission of the join event. - Implement proper session handling.

Affected packages (3)

CVSS scores

SourceVersionSeverityVector
osvCVSS 4.0—CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
osvCVSS 3.1MEDIUM4.3CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

References (6)