CVE-2019-1983 : Security Advisory and Response

Cisco Email Security Appliance and Cisco Content Security Management Appliance Denial of Service Vulnerability

Understanding CVE-2019-1983

This CVE involves a vulnerability in the email message filtering function of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) and Cisco Content Security Management Appliance (SMA) that could lead to a denial of service (DoS) attack.

What is CVE-2019-1983?

The flaw in the email message filtering function of Cisco AsyncOS Software for Cisco Email Security Appliance and Cisco Content Security Management Appliance allows an attacker to crash internal processes on the affected devices, resulting in a DoS scenario. The vulnerability stems from insufficient validation of email attachments.

The Impact of CVE-2019-1983

Attack Complexity: Low
Attack Vector: Network
Availability Impact: High
Base Score: 7.5 (High Severity)
No Confidentiality or Integrity Impact
No Privileges Required
User Interaction: None
Scope: Unchanged

Technical Details of CVE-2019-1983

Vulnerability Description

The vulnerability allows an attacker to send a specially crafted email attachment, causing repeated crashes in internal processes, leading to a DoS condition.

Affected Systems and Versions

Product: Cisco Email Security Appliance (ESA)
Vendor: Cisco
Versions: Not Applicable

Exploitation Mechanism

The attacker can exploit the vulnerability by sending an email with a specifically crafted attachment through the affected device, causing targeted processes to crash repeatedly.

Mitigation and Prevention

Immediate Steps to Take

Apply the latest security patches from Cisco.
Implement email attachment validation mechanisms.
Monitor email filtering processes for unusual activities.

Long-Term Security Practices

Regularly update and patch all software and firmware.
Conduct security training for employees on email security best practices.

Patching and Updates

Cisco has released patches to address this vulnerability.