Vulnerability Details : CVE-2021-22968
A bypass of adding remote files in Concrete CMS (previously concrete5) File Manager leads to remote code execution in Concrete CMS (concrete5) versions 8.5.6 and below.The external file upload feature stages files in the public directory even if they have disallowed file extensions. They are stored in a directory with a random name, but it's possible to stall the uploads and brute force the directory name. You have to be an admin with the ability to upload files, but this bug gives you the ability to upload restricted file types and execute them depending on server configuration.To fix this, a check for allowed file extensions was added before downloading files to a tmp directory.Concrete CMS Security Team gave this a CVSS v3.1 score of 5.4 AV:N/AC:H/PR:H/UI:R/S:C/C:N/I:H/A:NThis fix is also in Concrete version 9.0.0
Vulnerability category: File inclusionExecute code
Products affected by CVE-2021-22968
- cpe:2.3:a:concretecms:concrete_cms:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-22968
0.98%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 83 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-22968
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
|---|---|---|---|---|---|---|
|
6.5
|
MEDIUM | AV:N/AC:L/Au:S/C:P/I:P/A:P |
8.0
|
6.4
|
NIST | |
|
7.2
|
HIGH | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H |
1.2
|
5.9
|
NIST |
CWE ids for CVE-2021-22968
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The PHP application receives input from an upstream component, but it does not restrict or incorrectly restricts the input before its usage in "require," "include," or similar functions.Assigned by: support@hackerone.com (Secondary)
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The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.Assigned by: nvd@nist.gov (Primary)
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The product allows the upload or transfer of dangerous file types that are automatically processed within its environment.Assigned by: nvd@nist.gov (Primary)
References for CVE-2021-22968
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https://documentation.concretecms.org/developers/introduction/version-history/857-release-notes
8.5.7 Release Notes :: Concrete CMSRelease Notes;Vendor Advisory
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https://hackerone.com/reports/1350444
#1350444 A bypass of adding remote files in concrete5 FIlemanager leads to remote code executionExploit;Third Party Advisory
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