CVE-2021-21355 – typo3/cms-core

Package

Manager: composer
Name: typo3/cms-core
Vulnerable Version: >=10.0.0 <10.4.14 || >=11.0.0 <11.1.1 || >=9.0.0 <9.5.25

Severity

Level: High

CVSS v3.1: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L/E:F/RL:O/RC:C

CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:L/SC:N/SI:N/SA:N

EPSS: 0.00416 pctl0.60914

Details

Unrestricted File Upload in Form Framework ### Problem Due to the lack of ensuring file extensions belong to configured allowed mime-types, attackers can upload arbitrary data with arbitrary file extensions - however, default _fileDenyPattern_ successfully blocked files like _.htaccess_ or _malicious.php_. TYPO3 Extbase extensions, which implement a file upload and do not implement a custom _TypeConverter_ to transform uploaded files into _FileReference_ domain model objects are affected by the vulnerability as well, since the _UploadedFileReferenceConverter_ of _ext:form_ handles the file upload and will accept files of any mime-type which are persisted to the default location. In any way, uploaded files are placed in the default location _/fileadmin/user_upload/_, in most scenarios keeping the submitted filename - which allows attackers to directly reference files, or even correctly guess filenames used by other individuals, disclosing this information. No authentication is required to exploit this vulnerability. ### Solution Update to TYPO3 versions 8.7.40, 9.5.25, 10.4.14, 11.1.1 that fix the problem described. Type converter _UploadedFileReferenceConverter_ is not registered globally anymore and just handles uploaded files within the scope of the Form Framework. Guessable storage location has changed from _/fileadmin/user_upload/form\_\<random-hash\>/_ to _/fileadmin/form_uploads/<random-40-bit>_. Allowed mime-types must match expected file extensions (e.g. _application/pdf_ must be _.pdf_, and cannot be _.html_). Extbase extensions, who rely on the global availability of the _UploadedFileReferenceConverter_ must now implement a custom _TypeConverter_ to handle file uploads or explicitly implement the ext:form _UploadedFileReferenceConverter_ with appropriate setting for accepted mime-types. ### Credits Thanks to Sebastian Michaelsen, Marc Lindemann, Oliver Eglseder, Markus Volkmer, Jakob Kunzmann, Johannes Regner, Richie Lee who reported this issue, and to TYPO3 core & security team members Oliver Hader & Benni Mack, as well as TYPO3 contributor Ralf Zimmermann who fixed the issue. ### References * [TYPO3-CORE-SA-2021-002](https://typo3.org/security/advisory/typo3-core-sa-2021-002)

Metadata

Created: 2021-03-23T01:53:52Z
Modified: 2021-03-29T18:01:54Z
Source: https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/03/GHSA-2r6j-862c-m2v2/GHSA-2r6j-862c-m2v2.json
CWE IDs: ["CWE-434", "CWE-552"]
Alternative ID: GHSA-2r6j-862c-m2v2
Finding: F027
Auto approve: 1