9.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
6.8 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:M/Au:N/C:P/I:P/A:P
0.016 Low
EPSS
Percentile
87.3%
Before elFinder 2.1.58, the upload filter did not disallow the upload of .phar
files. As several Linux distributions are now shipping Apache configured in a way it will process these files as PHP scripts, attackers could gain arbitrary code execution on the server hosting the PHP connector (even in minimal configuration).
The issue has been addressed with https://github.com/Studio-42/elFinder/commit/75ea92decc16a5daf7f618f85dc621d1b534b5e1, associating .phar
files to the right MIME type. Unless explicitly allowed in the configuration, such files cannot be uploaded anymore. This patch is part of the last release of elFinder, 2.1.58.
If you can’t update to 2.1.58, make sure your connector is not exposed without authentication.
Server-side scripts can often be created as text files. Currently, elFinder has an appropriate MIME type set for file extensions that are generally runnable on a web server.
However, the server has various settings. In some cases, the executable file may be judged as “text/plain”. Therefore, elFinder installers should understand the extensions that can be executed on the web server where elFinder is installed, and check if there are any missing items in the elFinder settings.
The elFinder PHP connector has an option “additionalMimeMap” that specifies the MIME type for each extension. See #3295(comment) for more information.
If you have any questions or comments about this advisory, you can contact:
blog.sonarsource.com/elfinder-case-study-of-web-file-manager-vulnerabilities
github.com/Studio-42/elFinder
github.com/Studio-42/elFinder/commit/75ea92decc16a5daf7f618f85dc621d1b534b5e1
github.com/Studio-42/elFinder/issues/3295
github.com/Studio-42/elFinder/security/advisories/GHSA-qm58-cvvm-c5qr
nvd.nist.gov/vuln/detail/CVE-2021-23394
snyk.io/vuln/SNYK-PHP-STUDIO42ELFINDER-1290554
9.8 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
6.8 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:N/AC:M/Au:N/C:P/I:P/A:P
0.016 Low
EPSS
Percentile
87.3%