CVE-2021-46853 : Security Advisory and Response

CVE-2021-46853, assigned by MITRE, pertains to a vulnerability in Alpine versions before 2.25. Attackers can cause a denial of service by sending LIST or LSUB before STARTTLS.

Understanding CVE-2021-46853

This section provides an overview of the CVE-2021-46853 vulnerability.

What is CVE-2021-46853?

Alpine versions prior to 2.25 are susceptible to a denial-of-service vulnerability. Sending certain commands before a secure connection is initiated can crash the application.

The Impact of CVE-2021-46853

The vulnerability allows remote attackers to crash applications, leading to service disruption and potential system unavailability.

Technical Details of CVE-2021-46853

In this section, the technical details of CVE-2021-46853 are discussed.

Vulnerability Description

Alpine versions before 2.25 are vulnerable to a denial-of-service attack, triggered by executing LIST or LSUB commands before initiating a secure connection.

Affected Systems and Versions

Vendor: n/a
Product: n/a
Versions Affected: All versions prior to Alpine 2.25

Exploitation Mechanism

Attackers exploit this vulnerability by sending malicious LIST or LSUB commands before a secure connection (STARTTLS) is established.

Mitigation and Prevention

This section outlines steps to mitigate the CVE-2021-46853 vulnerability.

Immediate Steps to Take

Implement the latest version of Alpine (2.25 or newer)
Disable LIST and LSUB commands in the affected versions

Long-Term Security Practices

Regularly update software and apply security patches
Train users on safe email handling practices

Patching and Updates

Ensure timely patching by staying updated with security advisories and vendor patches.