CVE-2020-3404 : Exploit Details and Defense Strategies

A vulnerability in the persistent Telnet/Secure Shell (SSH) CLI of Cisco IOS XE Software could allow an authenticated, local attacker to gain shell access on an affected device and execute commands on the underlying operating system (OS) with root privileges.

Understanding CVE-2020-3404

This CVE involves a consent token bypass vulnerability in Cisco IOS XE Software.

What is CVE-2020-3404?

The vulnerability allows an authenticated, local attacker to gain shell access on an affected device and execute commands with root privileges due to insufficient enforcement of the consent token in authorizing shell access.

The Impact of CVE-2020-3404

CVSS Base Score: 6.7 (Medium Severity)
Attack Vector: Local
Confidentiality Impact: High
Integrity Impact: High
Availability Impact: High
Privileges Required: High
Scope: Unchanged
User Interaction: None
The exploit could lead to unauthorized access and execution of commands with elevated privileges.

Technical Details of CVE-2020-3404

This section provides detailed technical information about the vulnerability.

Vulnerability Description

The vulnerability arises from insufficient enforcement of the consent token in authorizing shell access, allowing attackers to gain unauthorized access.

Affected Systems and Versions

Affected Product: Cisco IOS XE Software
Affected Versions: Not applicable (n/a)

Exploitation Mechanism

Attackers can exploit the vulnerability by authenticating to the Telnet/SSH CLI on an affected device and requesting shell access.

Mitigation and Prevention

Protecting systems from CVE-2020-3404 requires immediate actions and long-term security practices.

Immediate Steps to Take

Apply vendor-provided patches or updates promptly.
Monitor network traffic for any signs of exploitation.
Restrict access to vulnerable systems.

Long-Term Security Practices

Implement the principle of least privilege to restrict user access.
Regularly update and patch systems to address known vulnerabilities.

Patching and Updates

Cisco has likely released patches or updates to address this vulnerability. Ensure timely installation of these patches to mitigate the risk of exploitation.