Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
None
Attack Vector
Network
0

CVE-2021-21355

Disclosure Date: March 23, 2021
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

TYPO3 is an open source PHP based web content management system. In TYPO3 before versions 8.7.40, 9.5.25, 10.4.14, 11.1.1, 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. Besides that, UploadedFileReferenceConverter transforming uploaded files into proper FileReference domain model objects handles possible file uploads for other extensions as well – given those extensions use the Extbase MVC framework, make use of FileReference items in their direct or inherited domain model definitions and did not implement their own type converter. In case this scenario applies, UploadedFileReferenceConverter accepts any file mime-type and persists files in the default location. In any way, uploaded files are placed in the default location _/fileadmin/userupload/, 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. This is fixed in versions 8.7.40, 9.5.25, 10.4.14, 11.1.1.

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CVSS V3 Severity and Metrics
Base Score:
8.6 High
Impact Score:
4.7
Exploitability Score:
3.9
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L
Attack Vector (AV):
Network
Attack Complexity (AC):
Low
Privileges Required (PR):
None
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
Low
Integrity (I):
High
Availability (A):
Low

General Information

Vendors

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Weaknesses

Additional Info

Technical Analysis