CVE-2020-28016 Explained : Impact and Mitigation

Exim 4 before 4.94.2 allows an off-by-two Out-of-bounds Write because "-F ''" is mishandled by parse_fix_phrase.

Understanding CVE-2020-28016

Exim vulnerability with potential for an Out-of-bounds Write due to mishandling of specific input.

What is CVE-2020-28016?

CVE-2020-28016 is a vulnerability in Exim 4 before version 4.94.2 that can lead to an off-by-two Out-of-bounds Write due to the mishandling of certain input.

The Impact of CVE-2020-28016

This vulnerability could be exploited by attackers to potentially execute arbitrary code or cause a denial of service (DoS) on affected systems.

Technical Details of CVE-2020-28016

Exim vulnerability details and affected systems.

Vulnerability Description

The vulnerability in Exim 4 before 4.94.2 arises from the mishandling of "-F ''" by parse_fix_phrase, leading to an off-by-two Out-of-bounds Write.

Affected Systems and Versions

Product: Exim
Vendor: N/A
Versions: All versions before 4.94.2

Exploitation Mechanism

Attackers can exploit this vulnerability by providing malicious input that triggers the mishandling of the "-F ''" sequence, potentially leading to unauthorized code execution or DoS.

Mitigation and Prevention

Steps to mitigate and prevent exploitation of CVE-2020-28016.

Immediate Steps to Take

Update Exim to version 4.94.2 or newer to patch the vulnerability.
Monitor for any unusual activities on the system that could indicate exploitation.

Long-Term Security Practices

Regularly update and patch all software to prevent known vulnerabilities.
Implement network security measures to restrict unauthorized access to Exim servers.

Patching and Updates

Ensure timely installation of security patches and updates for Exim to address vulnerabilities and enhance system security.