Username spoofing in OnionShare

CVE-2022-21696 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

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-005
  • Vulnerability type: Improper Input Sanitization
  • Threat level: Low

Description:

It is possible to change the username to that of another chat participant with an additional space character at the end of the name string.

Technical description:

Assumed users in Chat:

  • Alice
  • Bob
  • Mallory
  1. Mallory renames to Alice.
  2. Mallory sends message as Alice.
  3. Alice and Bob receive a message from Mallory disguised as Alice, which is hard to distinguish from the Alice
    in the web interface.

otf-005-a
otf-005-b

Other (invisible) whitespace characters were found to be working as well.

Impact:

An adversary with access to the chat environment can use the rename feature to impersonate other participants by adding whitespace characters at the end of the username.

Recommendation:

  • Remove non-visible characters from the username

Basic information

Type
reviewed
Severity
medium
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2022-01-21 23:20:14 UTC
Updated
2024-10-08 12:39:17 UTC
GitHub reviewed
2022-01-19 19:41:55 UTC
NVD published
2022-01-18 20:15:00 UTC

EPSS Score

Score Percentile
0.21% 43.35%

CVSS Scores

Base score Version Severity Vector
4.3 3.1 —
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
5.3 4.0 —
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network.
Attack complexity (AC:L)
Exploitation conditions are straightforward and stable.
Attack requirements (AT:N)
No additional preconditions are required beyond normal reachability.
Privileges required (PR:L)
Low privileges are required.
User interaction (UI:N)
No user interaction is required.
Vulnerable system confidentiality impact (VC:L)
Limited confidentiality impact on the vulnerable system.
Vulnerable system integrity impact (VI:N)
No integrity impact on the vulnerable system.
Vulnerable system availability impact (VA:N)
No availability impact on the vulnerable system.
Subsequent system confidentiality impact (SC:N)
No confidentiality impact on subsequent systems.
Subsequent system integrity impact (SI:N)
No integrity impact on subsequent systems.
Subsequent system availability impact (SA:N)
No availability impact on subsequent systems.

Identifiers

Type Value
GHSA GHSA-68vr-8f46-vc9f ↗
CVE CVE-2022-21696 ↗

CWEs

CWE id Name
CWE-20 Improper Input Validation

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
pip onionshare-cli >= 2.3, < 2.5 2.5 —

References

cvelogic Threat Intelligence