CVE-2018-18531: Insufficiently Random Values in kaptcha
Summary
CVE-2018-18531: Use of Insufficiently Random Values in penggle:kaptcha. Affects com.github.penggle:kaptcha versions < 2.3.2. No fix is published. How to fix ↓
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Background
The kaptcha package is a Java library used for generating CAPTCHA images. It provides functionality for creating random text strings that can be used to verify user input. The package is commonly used in web applications to prevent automated bots from accessing sensitive areas or performing malicious actions. However, versions up to 2.3.2 of kaptcha use the insecure Random function instead of SecureRandom for generating CAPTCHA values. This makes it easier for attackers to bypass access restrictions by brute-forcing the CAPTCHA.
Vulnerability Detail
The vulnerability (CVE-2018-18531) in kaptcha arises from the use of the Random function instead of SecureRandom for generating CAPTCHA values. The Random function does not provide sufficient randomness, making it easier for attackers to guess or brute-force the CAPTCHA values. This can lead to unauthorized access to sensitive areas of web applications or the ability to perform malicious actions. The vulnerability has a CVSS score of 9.8, indicating its critical severity.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
If updating the kaptcha package is not feasible at the moment, a possible workaround is to implement a custom solution for generating CAPTCHA values using SecureRandom. This can be done by extending the kaptcha library or implementing a separate CAPTCHA generation module. Here's an example of how to generate a random string using SecureRandom in Java:
import java.security.SecureRandom;
public class CustomCaptchaGenerator {
public String generateCaptcha() {
SecureRandom random = new SecureRandom();
byte[] bytes = new byte[8];
random.nextBytes(bytes);
return new String(bytes);
}
}
Conclusion
The vulnerability in kaptcha (CVE-2018-18531) arises from the use of the insecure Random function for generating CAPTCHA values. It is critical in severity with a CVSS score of 9.8. To fix this vulnerability, update the kaptcha package to version 2.3.3 or newer. If immediate updating is not possible, consider implementing a custom solution using SecureRandom. For further support on vulnerability remediation, contact DevNack.com.
See every vulnerability recorded for com.github.penggle:kaptcha →
FAQ
kaptcha is a Java library used for generating CAPTCHA images in web applications. It helps prevent automated bots from accessing sensitive areas or performing malicious actions.
The vulnerability (CVE-2018-18531) in kaptcha arises from the use of the insecure Random function instead of SecureRandom for generating CAPTCHA values. This makes it easier for attackers to bypass access restrictions by brute-forcing the CAPTCHA.
The vulnerability in kaptcha can lead to unauthorized access to sensitive areas of web applications or the ability to perform malicious actions. Attackers can exploit the weak randomness of CAPTCHA values to bypass access restrictions.
To fix this vulnerability, update the kaptcha package to a version that uses SecureRandom for generating CAPTCHA values. The latest version (2.3.3) addresses this issue.
If updating the kaptcha package is not feasible, you can implement a custom solution for generating CAPTCHA values using SecureRandom. See the 'workaround' section for an example.
