cbcvebase.
CVE-2023-41892
published 2023-09-13

CVE-2023-41892: Craft CMS is a platform for creating digital experiences. This is a high-impact, low-complexity attack vector. Users running Craft installations before 4.4.15…

PriorityP190critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
ITWEXPLOITVulnCheck KEVInitial access
Exploited in the wild
EPSS
92.92%
99.8th percentile
Craft CMS is a platform for creating digital experiences. This is a high-impact, low-complexity attack vector. Users running Craft installations before 4.4.15 are encouraged to update to at least that version to mitigate the issue. This issue has been fixed in Craft CMS 4.4.15.

Affected

8 ranges
VendorProductVersion rangeFixed in
craftcmscms
craftcmscms
craftcmscms
craftcmscms>= 4.0.0-RC1 < 4.4.154.4.15
craftcmscraft_cms>= 3.0.0 < 3.9.153.9.15
craftcmscraft_cms>= 4.0.0 < 4.14.154.14.15
craftcmscraft_cms>= 4.4.0 < 4.4.154.4.15
craftcmscraft_cms>= 5.0.0 < 5.6.175.6.17

Detection & IOCsextracted from sources · hover to see the quote

path/index.php
commandaction=conditions/render&test[userCondition]=craft\elements\conditions\users\UserCondition&config={"name":"test[userCondition]","as xyz":{"class":"\\GuzzleHttp\\Psr7\\FnStream", "__construct()": [{"close":null}],"_fn_close":"phpinfo"}}
filenameshell.php
filenamepwn1.msl
snort
alert http any any -> $HOME_NET any (msg:"ET WEB_SPECIFIC_APPS CraftCMS Remote Code Execution via ConditionsController Object Creation (CVE-2023-41892)"; flow:established,to_server; http.method; content:"POST"; http.request_body; content:"action|3d|conditions|2f|render"; content:"|3d|craft|5c|elements|5c|conditions|5c|"; fast_pattern; content:"|22 5f 5f|construct|28 29 22|"; reference:url,blog.calif.io/p/craftcms-rce; reference:cve,2023-41892; classtype:web-application-attack; sid:2056385; rev:1; metadata:affected_product CraftCMS, attack_target Server, tls_state TLSDecrypt, created_at 2024_10_02, cve CVE_2023_41892, deployment Perimeter, deployment Internal, deployment SSLDecrypt, confidence High, signature_severity Major, tag Exploit, updated_at 2024_10_02, mitre_tactic_id TA0001, mitre_tactic_name Initial_Access, mitre_technique_id T1190, mitre_technique_name Exploit_Public_Facing_Application; target:dest_ip;)
  • Exploit POST requests target /index.php with the body parameter `action=conditions/render`, which routes to the vulnerable ConditionsController. Detect POST requests to this endpoint containing this action parameter.
  • The exploit payload embeds `GuzzleHttp\Psr7\FnStream` as the class value in the `config` JSON parameter, combined with `__construct()` and `_fn_close` keys. Inspect POST body for this class name as a strong indicator of exploitation.
  • The Nuclei template matches a successful exploitation response by checking for the words `PHP Credits`, `PHP Group`, and `CraftCMS` together in the response body — indicating phpinfo() was executed.
  • The Metasploit module confirms the vulnerability is in `\craft\controllers\ConditionsController` via PHP object creation escalating to `\GuzzleHttp\Psr7\FnStream` methods. Monitor web server logs for POST requests to `/index.php` with `conditions/render` in the body.
  • The Snort/ET rule uses byte-level content matching: `action|3d|conditions|2f|render` (action=conditions/render) and `|3d|craft|5c|elements|5c|conditions|5c|` and `|22 5f 5f|construct|28 29 22|` ("__construct()") in the HTTP request body. Use these byte patterns for network-level detection.
  • Shodan/FOFA fingerprinting: CraftCMS instances can be identified by favicon hash `-47932290`. Use this to scope exposure of potentially vulnerable assets.
  • The deployed webshell is named `shell.php` and placed in the web document root. Monitor for creation of `shell.php` in web-accessible directories and HTTP requests to `shell.php?cmd=`.
  • ·The Imagick-based second-stage RCE (MSL file write) requires the PHP Imagick extension to be installed and enabled on the target server. Without it, only the phpinfo() probe via FnStream is achievable, not full webshell deployment.
  • ·The exploit is unauthenticated — no credentials or session are required. Any network-accessible Craft CMS instance on affected versions (4.0.0-RC1 through 4.4.14) is at risk without additional network controls.
  • ·CVE-2025-32432 is described as an additional fix for CVE-2023-41892, meaning patching to 4.4.15 alone may not be sufficient — versions before 4.14.15 (v4 branch) and 5.6.17 (v5 branch) remain vulnerable to the related bypass.

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vulncheck10.0CRITICAL
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