CVE-2021-22569 : Exploit Details and Defense Strategies

An issue in protobuf-java allowed the interleaving of com.google.protobuf.UnknownFieldSet fields in such a way that would be processed out of order. A small malicious payload can occupy the parser for several minutes by creating large numbers of short-lived objects that cause frequent, repeated pauses. Upgrading libraries beyond the vulnerable versions is recommended.

Understanding CVE-2021-22569

This CVE involves a Denial of Service vulnerability in the parsing procedure of protobuf-java.

What is CVE-2021-22569?

CVE-2021-22569 is a vulnerability that allows the interleaving of fields in a way that causes processing to be out of order, resulting in a Denial of Service condition.

The Impact of CVE-2021-22569

The impact of this vulnerability is significant as a small malicious payload can occupy the parser for several minutes, causing frequent pauses and potential service disruption.

Technical Details of CVE-2021-22569

This section delves into the specifics of the vulnerability.

Vulnerability Description

The vulnerability stems from the improper interleaving of fields in protobuf-java, leading to processing order issues that can be exploited for Denial of Service attacks.

Affected Systems and Versions

Google LLC protobuf-java: Versions less than 3.16.1, 3.18.2, and 3.19.2 are affected.
Google LLC protobuf-kotlin: Versions less than 3.18.2 and 3.19.2 are affected.
Google LLC google-protobuf [JRuby Gem]: Versions less than 3.19.2 are affected.

Exploitation Mechanism

Exploitation involves creating a small malicious payload that generates large numbers of short-lived objects, causing the parser to be occupied for extended periods, leading to a Denial of Service scenario.

Mitigation and Prevention

Preventive measures and steps to mitigate the impact of CVE-2021-22569.

Immediate Steps to Take

Update the affected libraries to versions 3.16.1, 3.18.2, and 3.19.2 or higher.
Monitor for any unusual processing pauses or delays that could indicate exploitation.

Long-Term Security Practices

Regularly update software libraries and dependencies to the latest secure versions.
Implement proactive monitoring to detect and respond to unusual activity that may point to DoS attempts.

Patching and Updates

Stay informed about security bulletins and updates from relevant vendors to ensure timely patching and protection against known vulnerabilities.