CVE-2020-16127 : Vulnerability Insights and Analysis

An Ubuntu-specific modification to AccountsService in versions before 0.6.55-0ubuntu13.2, among other earlier versions, would perform unbounded read operations on user-controlled ~/.pam_environment files, allowing an infinite loop if /dev/zero is symlinked to this location.

Understanding CVE-2020-16127

This CVE involves a vulnerability in the accountsservice package on Ubuntu systems.

What is CVE-2020-16127?

CVE-2020-16127 is a security flaw in the accountsservice package on Ubuntu systems that could lead to an infinite loop due to unbounded read operations on user-controlled ~/.pam_environment files.

The Impact of CVE-2020-16127

The impact of this vulnerability is rated as LOW severity with a CVSS base score of 2.8. It requires local access and user interaction to exploit, potentially causing denial of service through an infinite loop.

Technical Details of CVE-2020-16127

This section provides more in-depth technical details about the CVE.

Vulnerability Description

The vulnerability arises from unbounded read operations on user-controlled ~/.pam_environment files, leading to an infinite loop if /dev/zero is symlinked to this location.

Affected Systems and Versions

Product: accountsservice
Vendor: Freedesktop
Versions affected:
0.6.35-0ubuntu7.3
0.6.40-2ubuntu11
0.6.45-1ubuntu1
0.6.55-0ubuntu12~20.04.4
0.6.55-0ubuntu13

Exploitation Mechanism

The vulnerability requires an attacker to have local access to the system and user interaction to exploit the unbounded read operations on ~/.pam_environment files.

Mitigation and Prevention

Protecting systems from CVE-2020-16127 is crucial to maintaining security.

Immediate Steps to Take

Apply the necessary patches provided by the vendor.
Monitor for any unusual system behavior that could indicate exploitation.

Long-Term Security Practices

Regularly update and patch software to address known vulnerabilities.
Implement proper file permission settings to restrict access to sensitive system files.

Patching and Updates

Update the accountsservice package to versions that address the vulnerability.