CVE-2020-28010 : What You Need to Know

Exim 4 before 4.94.2 allows Out-of-bounds Write due to a buffer overflow vulnerability when the main function, running as setuid root, copies the current working directory pathname into a buffer that is too small.

Understanding CVE-2020-28010

This CVE entry describes a security vulnerability in Exim 4 before version 4.94.2.

What is CVE-2020-28010?

CVE-2020-28010 is a buffer overflow vulnerability in Exim 4 that allows an attacker to write outside the bounds of allocated memory, potentially leading to arbitrary code execution or a denial of service.

The Impact of CVE-2020-28010

The vulnerability can be exploited by an attacker to execute arbitrary code or cause a denial of service on systems running the affected versions of Exim 4.

Technical Details of CVE-2020-28010

Exim 4 before version 4.94.2 is susceptible to an Out-of-bounds Write vulnerability.

Vulnerability Description

The main function in Exim 4, when running as setuid root, copies the current working directory pathname into a buffer that is too small, leading to a buffer overflow.

Affected Systems and Versions

Product: Exim 4
Vendor: N/A
Versions affected: All versions before 4.94.2

Exploitation Mechanism

The vulnerability can be exploited by crafting a malicious payload to trigger the buffer overflow when Exim 4 attempts to copy the current working directory pathname.

Mitigation and Prevention

It is crucial to take immediate steps to mitigate the risks posed by CVE-2020-28010.

Immediate Steps to Take

Update Exim to version 4.94.2 or later to patch the vulnerability.
Implement least privilege principles to limit the impact of potential exploits.

Long-Term Security Practices

Regularly monitor security advisories and update Exim promptly.
Conduct security assessments and code reviews to identify and address vulnerabilities proactively.

Patching and Updates

Apply patches and updates provided by Exim to ensure the security of the mail server.