CVE-2019-1955 : What You Need to Know

Cisco Email Security Appliance Header Injection Vulnerability

Understanding CVE-2019-1955

This CVE involves a vulnerability in Cisco Email Security Appliances (ESA) that allows remote attackers to bypass user filters via Sender Policy Framework (SPF) messages.

What is CVE-2019-1955?

The vulnerability in Cisco AsyncOS Software for Cisco Email Security Appliances (ESA) allows attackers to send modified SPF packets to bypass configured header filters, potentially enabling harmful content to pass through.

The Impact of CVE-2019-1955

CVSS Base Score: 5.3 (Medium Severity)
Attack Vector: Network
Integrity Impact: Low
Privileges Required: None
Scope: Unchanged
This vulnerability could lead to unauthorized content passing through the device.

Technical Details of CVE-2019-1955

The following technical details provide insight into the vulnerability.

Vulnerability Description

Incomplete checking and validation of specific SPF messages in Cisco AsyncOS Software

Affected Systems and Versions

Affected Product: Cisco Email Security Appliance (ESA)
Vendor: Cisco
Versions: Unspecified

Exploitation Mechanism

Attackers can exploit the vulnerability by sending customized SPF packets to the affected device.

Mitigation and Prevention

Steps to address and prevent exploitation of CVE-2019-1955.

Immediate Steps to Take

Apply vendor-provided patches or updates promptly.
Monitor network traffic for any suspicious activity related to SPF messages.

Long-Term Security Practices

Regularly update and patch all software and firmware on the affected devices.
Implement strong email security protocols and filters to mitigate risks.

Patching and Updates

Check for and apply patches released by Cisco to address the vulnerability.