CVE-2017-3818 : Security Advisory and Response

A vulnerability in the Multipurpose Internet Mail Extensions (MIME) scanner of Cisco AsyncOS Software for Cisco Email Security Appliances could allow a remote attacker to bypass user filters. This flaw is known as a Malformed MIME Header Filtering Bypass.

Understanding CVE-2017-3818

This CVE identifies a security vulnerability in Cisco AsyncOS Software for Cisco Email Security Appliances that could be exploited by an unauthenticated remote attacker.

What is CVE-2017-3818?

The vulnerability allows attackers to bypass user filters on the device, potentially compromising email security.

The Impact of CVE-2017-3818

The flaw could enable a remote attacker to circumvent configured user filters on the affected devices, posing a risk to email security.

Technical Details of CVE-2017-3818

This section provides more technical insights into the vulnerability.

Vulnerability Description

The flaw exists in the MIME scanner of Cisco AsyncOS Software for Cisco Email Security Appliances, affecting all releases before the initial fixed release.

Affected Systems and Versions

Product: Cisco AsyncOS 9.7.1-066
Affected Version: Cisco AsyncOS 9.7.1-066

Exploitation Mechanism

The vulnerability can be exploited by a remote attacker who is not authenticated, allowing them to bypass user filters on the device.

Mitigation and Prevention

Protecting systems from CVE-2017-3818 is crucial for maintaining email security.

Immediate Steps to Take

Update to the fixed releases, such as 9.8.0-092, to mitigate the vulnerability.
Implement additional security measures to enhance email filtering and scanning.

Long-Term Security Practices

Regularly monitor and update email security systems to address emerging threats.
Conduct security assessments to identify and remediate vulnerabilities proactively.

Patching and Updates

Apply patches and updates provided by Cisco to ensure the security of the Email Security Appliances.