Executive Summary

[{'type': 'paragraph', 'content': "CVE-2020-37123 is a critical remote code execution vulnerability in Pinger version 1.0, a PHP-based web application used for monitoring network devices. The vulnerability exists because the application improperly handles user input in the ping.php script, specifically through the 'ping' and 'socket' parameters."}, {'type': 'paragraph', 'content': 'Attackers can inject shell commands by exploiting unsanitized input, allowing them to execute arbitrary system commands on the server. This is possible because the application uses shell_exec() to run system commands like ping and netcat (nc) without validating or sanitizing the input parameters.'}, {'type': 'paragraph', 'content': 'Exploitation examples include injecting PHP code via these parameters to create malicious PHP files (e.g., a web shell) on the server, enabling full remote code execution.'}] [1, 3]

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Impact Analysis

This vulnerability allows remote attackers to execute arbitrary commands on the server hosting the Pinger application without any privileges or user interaction.

The impact includes the ability to write arbitrary PHP files, such as web shells, which can lead to full system compromise.

Consequently, attackers can gain unauthorized access, manipulate or steal sensitive data, disrupt services, and potentially use the compromised server as a foothold for further attacks.

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Compliance Impact

I don't know

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Detection Guidance

[{'type': 'paragraph', 'content': "This vulnerability can be detected by testing the vulnerable parameters in the ping.php script for command injection. Specifically, the 'ping' and 'socket' GET parameters accept user input that is directly passed to shell commands without sanitization."}, {'type': 'paragraph', 'content': 'You can attempt to inject shell commands via these parameters to check if arbitrary commands are executed. For example, sending requests like the following can reveal the vulnerability by creating a PHP file on the server:'}, {'type': 'list_item', 'content': "http://localhost/pinger/ping.php?ping=;echo '<?php phpinfo(); ?>' >info.php"}, {'type': 'list_item', 'content': "http://localhost/pinger/ping.php?socket=;echo '<?php phpinfo(); ?>' >info.php"}, {'type': 'paragraph', 'content': "If the file 'info.php' is created and accessible, it confirms the vulnerability. This method leverages the unsanitized input to execute shell commands remotely."}] [1]

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Mitigation Strategies

[{'type': 'paragraph', 'content': 'Immediate mitigation steps include restricting access to the vulnerable ping.php script to trusted users or internal networks only.'}, {'type': 'paragraph', 'content': 'Disabling or removing the vulnerable Pinger 1.0 application until a secure patch or update is available is recommended.'}, {'type': 'paragraph', 'content': "Implement input validation and sanitization on the 'ping' and 'socket' parameters to prevent shell metacharacter injection."}, {'type': 'paragraph', 'content': 'Consider using safer alternatives to shell_exec() for executing system commands, or avoid executing system commands with user input altogether.'}, {'type': 'paragraph', 'content': 'Monitor server logs for suspicious requests targeting ping.php with unusual parameter values that may indicate exploitation attempts.'}] [1, 2, 3]

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