CVE-2017-2909 : Exploit Details and Defense Strategies

Cesanta Mongoose 6.8 library contains a vulnerability that allows an attacker to trigger an infinite loop in the DNS server functionality, leading to a Denial of Service (DoS) condition.

Understanding CVE-2017-2909

This CVE involves a programming error in the DNS server functionality of the Cesanta Mongoose 6.8 library, potentially resulting in a DoS attack.

What is CVE-2017-2909?

The vulnerability in Cesanta Mongoose 6.8 library allows an attacker to exploit the DNS server functionality, causing the program to enter an infinite loop when receiving a specially crafted DNS request. This loop leads to high CPU usage and a DoS condition.

The Impact of CVE-2017-2909

CVSS Base Score: 7.5 (High)
Attack Vector: Network
Attack Complexity: Low
Availability Impact: High
The vulnerability can be exploited remotely without requiring privileges, impacting the availability of the system.

Technical Details of CVE-2017-2909

The technical aspects of the vulnerability in Cesanta Mongoose 6.8 library.

Vulnerability Description

The programming error in the DNS server functionality allows for an infinite loop.
A carefully crafted DNS request can trigger the loop, causing high CPU usage and a DoS condition.

Affected Systems and Versions

Affected Product: Mongoose
Vendor: Cesanta
Affected Version: 6.8

Exploitation Mechanism

An attacker can exploit the vulnerability by sending a malicious packet through the network, triggering the infinite loop in the DNS server functionality.

Mitigation and Prevention

Steps to mitigate and prevent the exploitation of CVE-2017-2909.

Immediate Steps to Take

Update the Cesanta Mongoose library to a patched version that addresses the infinite loop issue.
Implement network-level controls to filter out potentially malicious DNS requests.

Long-Term Security Practices

Regularly monitor CPU usage for abnormal spikes that could indicate a DoS attack.
Conduct security assessments and code reviews to identify and address similar vulnerabilities in the future.

Patching and Updates

Stay informed about security updates and patches released by Cesanta for the Mongoose library.
Apply patches promptly to ensure the system is protected against known vulnerabilities.