CVE-2020-35680 : What You Need to Know

OpenSMTPD before 6.8.0p1 allows remote attackers to cause a denial of service via crafted client activity.

Understanding CVE-2020-35680

OpenSMTPD vulnerability leading to a denial of service due to a NULL pointer dereference and daemon crash.

What is CVE-2020-35680?

OpenSMTPD before version 6.8.0p1 is susceptible to a denial of service attack caused by a specific pattern of client activity.

The Impact of CVE-2020-35680

The vulnerability allows remote attackers to trigger a denial of service by exploiting a flaw in the filter state machine of OpenSMTPD.

Technical Details of CVE-2020-35680

OpenSMTPD vulnerability technical specifics.

Vulnerability Description

The issue arises from smtpd/lka_filter.c in OpenSMTPD before 6.8.0p1, where the filter state machine fails to maintain the I/O channel properly, leading to a NULL pointer dereference and daemon crash.

Affected Systems and Versions

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

Exploitation Mechanism

Remote attackers can exploit this vulnerability by manipulating the client activity pattern to trigger the denial of service.

Mitigation and Prevention

Protect systems from CVE-2020-35680.

Immediate Steps to Take

Update OpenSMTPD to version 6.8.0p1 or later to mitigate the vulnerability.
Monitor network traffic for any suspicious activity that could indicate an ongoing attack.

Long-Term Security Practices

Regularly update and patch software to prevent known vulnerabilities.
Implement network segmentation to limit the impact of potential attacks.
Conduct regular security audits and penetration testing to identify and address security weaknesses.

Patching and Updates

Apply patches and updates provided by OpenSMTPD to address CVE-2020-35680.