Ecosyste.ms: Advisories

Security Advisories: GSA_kwCzR0hTQS05OXA4LTlwMmMtNDlqNM0kew

Improper Access Control in Onionshare

Between September 26, 2021 and October 8, 2021, Radically Open Security conducted a penetration test of OnionShare 2.4, funded by the Open Technology Fund's 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.

Permalink: https://github.com/advisories/GHSA-99p8-9p2c-49j4
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS05OXA4LTlwMmMtNDlqNM0kew
Source: GitHub Advisory Database
Origin: Unspecified
Severity: Moderate
Classification: General
Published: over 2 years ago
Updated: about 1 year ago

CVSS Score: 4.3
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Identifiers: GHSA-99p8-9p2c-49j4, CVE-2022-21695
References:

• https://github.com/onionshare/onionshare/security/advisories/GHSA-99p8-9p2c-49j4
• https://nvd.nist.gov/vuln/detail/CVE-2022-21695
• https://github.com/onionshare/onionshare/releases/tag/v2.5
• https://github.com/advisories/GHSA-99p8-9p2c-49j4

Repository: https://github.com/onionshare/onionshare
Blast Radius: 1.0

Affected Packages