CVE-2021-43174 : Exploit Details and Defense Strategies

NLnet Labs Routinator versions 0.9.0 up to and including 0.10.1 support the gzip transfer encoding when querying RRDP repositories. This encoding can cause an out-of-memory crash due to a vulnerability.

Understanding CVE-2021-43174

This CVE involves an out-of-memory crash vulnerability in Routinator caused by the use of the gzip transfer encoding when querying RRDP repositories.

What is CVE-2021-43174?

NLnet Labs Routinator versions 0.9.0 to 0.10.1 are susceptible to an out-of-memory crash triggered by an RRDP repository utilizing gzip encoding that leads to excessive memory consumption during XML data processing.

The Impact of CVE-2021-43174

The vulnerability can be exploited to execute a denial-of-service attack by causing Routinator to run out of memory during XML data parsing.

Technical Details of CVE-2021-43174

This section covers the technical specifics of the vulnerability.

Vulnerability Description

The issue arises in Routinator versions 0.9.0 to 0.10.1 when processing XML data with excess white space compressed using gzip, resulting in memory overflow and a crash.

Affected Systems and Versions

Product: Routinator
Vendor: NLnet Labs
Versions Affected: up to 0.10.1

Exploitation Mechanism

An attacker can craft XML data with excessive white space, compress it using the gzip scheme, and send it to an RRDP repository to trigger the out-of-memory crash in affected Routinator versions.

Mitigation and Prevention

Protect systems from CVE-2021-43174 by following these mitigation strategies.

Immediate Steps to Take

Upgrade Routinator to a non-vulnerable version above 0.10.1.
Implement input validation to restrict the size of compressed data.

Long-Term Security Practices

Regularly monitor and update software for security patches.
Train staff on identifying and responding to security vulnerabilities.

Patching and Updates

NLnet Labs has released updated versions of Routinator to address this vulnerability.