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Account compromise by man-in-the-middle attack

High
Kenny2github published GHSA-gvpg-23fh-8g75 Apr 13, 2021

Package

ScratchOAuth2 (MediaWiki extension)

Affected versions

<9220c2a

Patched versions

>=9220c2a

Description

Impact

Any ScratchOAuth2-related data normally accessible and modifiable by a user can be read and modified by a third party.

  1. Scratch user visits 3rd party site
  2. 3rd party site asks user for Scratch username
  3. 3rd party site pretends to be user and gets login code from ScratchOAuth2
  4. 3rd party site gives code to user and instructs them to post it on their profile
  5. User posts code on their profile, not knowing it is a ScratchOAuth2 login code
  6. 3rd party site completes login with ScratchOAuth2
  7. 3rd party site has full access to anything the user could do if they directly logged in

Patches

Warning included in code itself to only trust codes from the right site. (Commit 9220c2a)

Workarounds

Do not trust login codes that perfectly match the original ScratchOAuth2 format (fivec:harac:tersc:olons:epara:ted...).

For more information

If you have any questions or comments about this advisory:

Severity

High
8.0
/ 10

CVSS base metrics

Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
None
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N

CVE ID

CVE-2021-29437

Weaknesses

No CWEs

Credits