CVE-2020-13443 Information

Description

ExpressionEngine before 5.3.2 allows remote attackers to upload and execute arbitrary code in a .php20 file via Compose Msg Add attachment and Save As Draft actions. A user with low privileges (member) is able to upload this. It is possible to bypass the MIME type check and file-extension check while uploading new files. Short aliases are not used for an attachment; instead direct access is allowed to the uploaded files. It is possible to upload PHP only if one has member access or registration/forum is enabled and one can create a member with the default group id of 5. To exploit this one must to be able to send and compose messages (at least).

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Reference

https://expressionengine.com/blog https://gist.github.com/mariuszpoplwski/51604d8a6d7d78fffdf590c25e844e09

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

8.8