CVE-2023-49316: phpseclib Denial of Service Vulnerability
Summary
CVE-2023-49316: phpseclib vulnerable to denial of service. Affects phpseclib/phpseclib versions >= 3.0.0, < 3.0.34. Fixed in 3.0.34. How to fix ↓
Also tracked for
- php-phpseclib3 · Debian:12
The same CVE-2023-49316 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
phpseclib is a PHP library that provides a secure method for communicating with remote servers using various cryptographic protocols. It is widely used for tasks such as SSH, SFTP, and encryption. The library offers a range of functionality, including support for binary fields. However, versions prior to 3.0.34 are vulnerable to a denial of service attack when excessively large degrees are used in binary fields.
Vulnerability Detail
The vulnerability in phpseclib arises from a lack of proper input validation in the Math/BinaryField.php file. By supplying an excessively large degree value in binary fields, an attacker can trigger a denial of service condition. This can lead to resource exhaustion, causing the affected application to become unresponsive or crash. The impact of this vulnerability can be severe, especially in scenarios where the library is used in critical systems or services.
How To Fix
Minimum fixed version
3.0.34
This is the first release that contains the fix.
composer require phpseclib/phpseclib:3.0.34Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, developers can implement input validation checks on the degree values provided to binary fields. By enforcing reasonable limits on the degree size, the risk of triggering the denial of service condition can be mitigated. Here is an example of how to perform input validation in PHP:
$degree = $_POST['degree'];
if ($degree > 0 && $degree <= MAX_DEGREE) {
// Process the binary field
} else {
// Handle invalid degree
}
Conclusion
In conclusion, phpseclib versions prior to 3.0.34 are vulnerable to a denial of service attack due to improper input validation in binary fields. To mitigate this vulnerability, it is crucial to upgrade to the latest secure version of phpseclib. Implementing input validation checks can serve as a temporary workaround. For further assistance or support in vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for phpseclib/phpseclib →
FAQ
phpseclib is a PHP library that provides secure communication with remote servers using cryptographic protocols such as SSH and SFTP. It is widely used for tasks like encryption and secure file transfer.
The vulnerability in phpseclib can lead to a denial of service condition, causing the affected application to become unresponsive or crash. This can have severe consequences, especially in critical systems or services.
To fix this vulnerability, it is recommended to upgrade to phpseclib version 3.0.34 or later. This version includes a fix for the input validation issue. Update your dependencies and ensure you are using the latest secure version of phpseclib.
As a temporary workaround, you can implement input validation checks on the degree values provided to binary fields. By enforcing reasonable limits on the degree size, the risk of triggering the denial of service condition can be mitigated.
You can find more information about this vulnerability in the official GitHub Advisory Database. The provided source link contains the detailed advisory for this specific vulnerability.
References
Related vulnerabilities
Recent vulnerabilities recorded for phpseclib/phpseclib.
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