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GHSA-99p8-9p2c-49j4

MediumCVSS 4.3 / 10
Published Jan 21, 2022·Last modified Oct 8, 2024
Affected Components(0)

No affected components available

Description

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.
Risk Scores
Base Score
4.3

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. The attacker needs the user to perform some action, like clicking a link. The impact is confined to the system where the vulnerability exists. There is a low impact on the confidentiality of the information.

Threat Intelligence
4.0

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
0.85%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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