CVE-2019-18634 : Exploit Details and Defense Strategies

A stack-based buffer overflow vulnerability exists in the privileged sudo process of Sudo versions before 1.8.26 when the pwfeedback setting is enabled in the /etc/sudoers file. This vulnerability can be exploited by providing a lengthy string to the stdin of the getln() function in the tgetpass.c file.

Understanding CVE-2019-18634

This CVE involves a buffer overflow vulnerability in Sudo versions prior to 1.8.26 when the pwfeedback setting is enabled.

What is CVE-2019-18634?

CVE-2019-18634 is a stack-based buffer overflow vulnerability in the sudo process of Sudo versions before 1.8.26. It can be exploited when the pwfeedback setting is enabled in the /etc/sudoers file.

The Impact of CVE-2019-18634

The exploitation of this vulnerability can lead to a security breach where an attacker can execute arbitrary code or crash the sudo process, potentially compromising the system's integrity and confidentiality.

Technical Details of CVE-2019-18634

This section provides more technical insights into the vulnerability.

Vulnerability Description

The vulnerability allows an attacker to trigger a stack-based buffer overflow in the sudo process by providing a long string to the getln() function in the tgetpass.c file.

Affected Systems and Versions

Sudo versions before 1.8.26
Systems with the pwfeedback setting enabled in the /etc/sudoers file

Exploitation Mechanism

To exploit the vulnerability, an attacker must provide a lengthy string to the stdin of the getln() function in the tgetpass.c file.

Mitigation and Prevention

Protecting systems from CVE-2019-18634 requires immediate actions and long-term security practices.

Immediate Steps to Take

Update Sudo to version 1.8.26 or later to mitigate the vulnerability.
Disable the pwfeedback setting in the /etc/sudoers file if not required.
Monitor system logs for any suspicious activities.

Long-Term Security Practices

Regularly update software and apply security patches promptly.
Implement the principle of least privilege to restrict access rights.
Conduct regular security audits and penetration testing to identify vulnerabilities.

Patching and Updates

Apply the latest security updates provided by Sudo to address CVE-2019-18634.