Empty Password Authentication Bypass in Linux-Pam
Summary
CVE-2020-27780: A flaw was found in Linux-Pam in versions prior to 1.5.1 in the way it handle empty passwords for non-existing users. Affects linux-pam across 2 version ranges.
< 1.5.1
>= 62d826471e87e27b39a36ccbeee58999e2514a92, < 225f17470eed9f44282f435ad1ed64c94d9a2ddf
Fixed in 1.5.1. How to fix ↓
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Background
Linux-Pam is a library that provides a flexible and secure system authentication mechanism for Linux systems. It is responsible for authenticating users and managing their access to various services. This vulnerability affects versions of Linux-Pam prior to 1.5.1. The vulnerability allows an attacker to bypass authentication when attempting to log in with an empty password for a non-existing user. The flaw occurs because Linux-Pam tries to authenticate with the root user when the specified user does not exist, and it successfully authenticates if the password is empty.
Vulnerability Detail
The vulnerability (CVE-2020-27780) in Linux-Pam allows an attacker to gain unauthorized access to a system by exploiting the empty password authentication bypass. When a user with an empty password attempts to log in, Linux-Pam incorrectly authenticates the user as the root user. This can lead to various security risks, such as unauthorized access to sensitive data, privilege escalation, and potential system compromise. The vulnerability has a CVSS score of 9.8, indicating its critical severity.
How To Fix
Minimum fixed version
1.5.1
This is the first release that contains the fix.
sudo apk add --upgrade linux-pamTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a workaround, you can enforce strong password policies and ensure that all user accounts have non-empty passwords. This will prevent the exploitation of the empty password authentication bypass vulnerability. Additionally, regularly monitoring and auditing user accounts can help detect any unauthorized access attempts.
Conclusion
The empty password authentication bypass vulnerability in Linux-Pam (CVE-2020-27780) poses a critical security risk, allowing unauthorized access to systems. It is crucial to update Linux-Pam to version 1.5.1 or later to mitigate this vulnerability. Regularly enforcing strong password policies and monitoring user accounts can also help prevent unauthorized access attempts. For further assistance and support in vulnerability remediation, please contact DevNack.com.
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FAQ
Linux-Pam is a library that provides system authentication for Linux systems. It manages user authentication and access to various services.
Versions of Linux-Pam prior to 1.5.1 are affected by this vulnerability.
When a non-existing user with an empty password attempts to log in, Linux-Pam tries to authenticate with the root user. If the password is empty, the authentication is successful, granting unauthorized access.
The vulnerability can lead to unauthorized access to sensitive data, privilege escalation, and potential system compromise.
To fix the vulnerability, update Linux-Pam to version 1.5.1 or later using the package manager specific to your Linux distribution.
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