Summary
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-003
- Vulnerability type: Improper Access Control
- Threat level: Moderate
Description:
Anyone with access to the chat environment can write messages disguised as another chat participant.
Technical description:
Prerequisites:
- Alice and Bob are legitimate users
- A third user has access to the chat environment
This screenshot shows Alice (glimpse-depress) and Bob (blinker-doorpost) joined a chatroom and are the only participants in the chatroom. Then the non-listed user squad-nursing writes a message in the chatroom without being visible in the list of users. The sending of the message itself is not required but was done here to show the initial access. The non-listed participant now renames himself to Bob and writes another message, seemingly coming from Bob.
This can be reproduced by slightly modifying the client-side JavaScript. The joined emit needs to be removed from the socket.on(connect) event handler. Therefore a client is not listed in the userlist and has no active session.
This can be done either via a crafted client or runtime modification of the chat.js script in the browser's internal debugger.
It is still possible to call the text method and send text to the chat via websocket.
It is also possible to call the update_username function and choose an existing username from the chat.
Afterwards the hidden user can send messages that are displayed as coming from the impersonated user. There is no way to distinguish between the fake and original message.
Impact
An adversary with access to the chat environment can impersonate existing chat participants and write messages but not read the conversation. The similar exploit described in OTF-004 (page 19) has only slightly more requirements but also allows for reading.
The application does not adequately verify the identity of a user, device, or process before granting access. Typical impact: unauthorized access to functions or data reserved for authenticated parties.
CVE-2022-21692 has a CVSS score of 4.3 (Medium). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.5); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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- Implement proper session handling
Frequently Asked Questions
- What is CVE-2022-21692? CVE-2022-21692 is a medium-severity improper authentication vulnerability in onionshare-cli (pip), affecting versions >= 2.3, < 2.5. It is fixed in 2.5. The application does not adequately verify the identity of a user, device, or process before granting access.
- How severe is CVE-2022-21692? CVE-2022-21692 has a CVSS score of 4.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of onionshare-cli are affected by CVE-2022-21692? onionshare-cli (pip) versions >= 2.3, < 2.5 is affected.
- Is there a fix for CVE-2022-21692? Yes. CVE-2022-21692 is fixed in 2.5. Upgrade to this version or later.
- Is CVE-2022-21692 exploitable, and should I be worried? Whether CVE-2022-21692 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2022-21692 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2022-21692? Upgrade
onionshare-clito 2.5 or later.