CVE-2022-43766 - Denial of Service in Apache IoTDB via REGEXP Queries Explained

Apache IoTDB (Internet of Things Database) is a popular, open-source time-series database for managing massive amounts of device data. But, if you are using an affected version, you should know about CVE-2022-43766: a denial-of-service (DoS) vulnerability related to REGEXP queries. Here we’ll break down what happened, how attackers could exploit it, see some code, and what you should do—using plain, practical language.

What is CVE-2022-43766?

Discovered: Late 2022
Affected Software:

.13. up to .13.2

Vulnerability:
If you run IoTDB on Java 8, certain untrusted (malicious or poorly designed) patterns passed to the SQL REGEXP operator in queries can cause unmanaged resource consumption, making your server slow or completely non-responsive (denial of service).

IoTDB is often used at the edge or in cloud to handle billions of tight, automated device records.

- If someone can halt or slow down the database with just a crafted query, it can break dashboards, data ingestion, or industrial applications.
- This is critical in environments where queries come from external sources or less-trusted accounts.

How Does the Exploit Work?

Java’s Pattern implementation is prone to what's called “catastrophic backtracking” for certain regular expressions, especially poorly constructed ones, like those with lots of wildcards or nested quantifiers.

In these affected IoTDB versions, the filtering REGEXP is exposed without much validation. If an attacker submits something like:

SELECT * FROM root.devices
WHERE label REGEXP '^(a+)+$'

and your data contains long sequences, Java’s regular expression engine can get “stuck” checking for matches, eating up CPU and RAM.

Here’s an example REGEXP pattern that can trigger catastrophic backtracking

SELECT *
FROM root.sensors
WHERE sn REGEXP '(a+)+$'

If sn contains a long string of "a"s (like "aaaaaaaaaa..."), the query may take minutes or hours to process, blocking your system.

This is what IoTDB does under the hood (simplified)

import java.util.regex.Pattern;
import java.util.regex.Matcher;

public class RegexTest {
    public static void main(String[] args) {
        String regex = "(a+)+$";
        String target = "a".repeat(10000);
        Pattern pattern = Pattern.compile(regex);
        Matcher matcher = pattern.matcher(target);
        System.out.println(matcher.matches());
    }
}

Running this will stall or freeze your process, maxing out the CPU, especially with Java 8's regex engine.

Original References

- Apache IoTDB Security Advisory - CVE-2022-43766
- National Vulnerability Database Entry
- GitHub Issue & Patch

How to Protect Yourself

1. Upgrade IoTDB

Upgrade immediately to version .13.3 or newer.

Direct download: IoTDB Releases

These versions restrict dangerous REGEXP patterns and fix untrusted pattern handling.

2. Move to modern Java

If you upgrade to Java 9 or later, the REGEXP engine is more robust against these attacks.

- However, upgrading IoTDB is still best because validation is improved regardless of Java version.

3. Restrict REGEXP Queries

Block or limit access to users who can perform arbitrary REGEXP queries, at least until you upgrade.

4. Monitor Resource Usage

Conclusion

CVE-2022-43766 is a textbook example of how something as simple as a SQL filter can freeze an entire database instance. If you are running any IoTDB .12.2-.12.6 or .13.-.13.2 with Java 8, you need to upgrade right now.

Timeline

Published on: 10/26/2022 16:15:00 UTC
Last modified on: 10/28/2022 17:43:00 UTC