CVE-2020-35679 : Exploit Details and Defense Strategies

OpenSMTPD before 6.8.0p1 is vulnerable to a memory leak due to a lack of regfree in smtpd/table.c, potentially triggered by malicious messages.

Understanding CVE-2020-35679

OpenSMTPD before 6.8.0p1 is susceptible to a memory leak issue that could be exploited by attackers.

What is CVE-2020-35679?

This CVE refers to a vulnerability in OpenSMTPD before version 6.8.0p1 that allows attackers to cause a significant memory leak by sending messages to an instance performing numerous regex lookups.

The Impact of CVE-2020-35679

The vulnerability could be exploited by malicious actors to trigger a memory leak, potentially leading to denial of service or other security implications.

Technical Details of CVE-2020-35679

OpenSMTPD before 6.8.0p1 is affected by this vulnerability.

Vulnerability Description

The issue arises from a missing regfree in smtpd/table.c, enabling attackers to induce a memory leak through crafted messages.

Affected Systems and Versions

Product: OpenSMTPD
Vendor: N/A
Versions: All versions before 6.8.0p1

Exploitation Mechanism

Attackers can exploit this vulnerability by sending specially crafted messages to an OpenSMTPD instance that performs multiple regex lookups, leading to a significant memory leak.

Mitigation and Prevention

Immediate action and long-term security practices are crucial to mitigate the risks associated with CVE-2020-35679.

Immediate Steps to Take

Update OpenSMTPD to version 6.8.0p1 or later to address the memory leak vulnerability.
Monitor system logs for any unusual memory consumption that could indicate exploitation.

Long-Term Security Practices

Regularly update and patch software to prevent known vulnerabilities.
Implement network and email security measures to detect and block malicious messages.

Patching and Updates

Apply patches and updates provided by OpenSMTPD to fix the memory leak vulnerability and enhance system security.