CVE-2020-28019 : Exploit Details and Defense Strategies

Exim 4 before 4.94.2 has Improper Initialization that can lead to recursion-based stack consumption or other consequences. This occurs because use of certain getc functions is mishandled when a client uses BDAT instead of DATA.

Understanding CVE-2020-28019

Exim 4 before version 4.94.2 is vulnerable to Improper Initialization, potentially leading to stack consumption due to mishandling of getc functions.

What is CVE-2020-28019?

CVE-2020-28019 is a vulnerability in Exim 4 before version 4.94.2 that allows for recursion-based stack consumption or other adverse effects when specific getc functions are improperly handled.

The Impact of CVE-2020-28019

The vulnerability can be exploited by a client using BDAT instead of DATA, potentially leading to stack consumption or other consequences.

Technical Details of CVE-2020-28019

Exim 4 before 4.94.2 is affected by this vulnerability.

Vulnerability Description

The issue arises from Improper Initialization, specifically mishandling of getc functions when a client opts for BDAT over DATA.

Affected Systems and Versions

Product: Exim 4
Vendor: N/A
Versions affected: N/A

Exploitation Mechanism

The vulnerability can be exploited when a client uses BDAT instead of DATA, triggering the mishandling of getc functions.

Mitigation and Prevention

It is crucial to take immediate steps to address and prevent the exploitation of CVE-2020-28019.

Immediate Steps to Take

Update Exim to version 4.94.2 or newer to mitigate the vulnerability.
Monitor for any unusual stack consumption or system behavior.

Long-Term Security Practices

Regularly update and patch Exim to ensure the latest security fixes are in place.
Implement network security measures to detect and prevent potential attacks.

Patching and Updates

Apply patches and updates provided by Exim promptly to address security vulnerabilities.