Recently, a critical vulnerability has been discovered in Elasticsearch, assigned as CVE-2024-52981, which affects the way it processes Well-KnownText (WKT) formatted strings with nested GeometryCollection objects. This vulnerability can lead to a stack overflow error, resulting in potential Denial of Service (DoS) or even arbitrary code execution attacks. In this blog post, we will dive deeper into the details of this vulnerability, discuss its potential impact, and provide recommendations on how to mitigate its effects.

Exploit Details

The vulnerability stems from Elasticsearch's handling of WKT formatted strings, specifically in parsing the nested GeometryCollection objects. An adversary can exploit this vulnerability to cause a stack overflow error by triggering a large recursion through carefully crafted malicious WKT strings. This can lead to a Denial of Service attack, where Elasticsearch services will become nonoperational, resulting in service disruptions and possibly data loss.

Here's an example code snippet that can trigger the vulnerability by generating a malicious WKT string with deeply nested GeometryCollection objects:

def generate_malicious_wkt_string(depth: int) -> str:
    wkt = "GEOMETRYCOLLECTION("
    for _ in range(depth):
        wkt += "GEOMETRYCOLLECTION("
    wkt += "POINT( )"
    for _ in range(depth):
        wkt += ")"
    return wkt

# Example usage to create a deeply nested malicious WKT string:
malicious_wkt = generate_malicious_wkt_string(10000)  # Depth value can be adjusted as needed

This code snippet creates a malicious WKT string by nesting GeometryCollection objects repeatedly, which, when processed by Elasticsearch, triggers the vulnerable code path that can cause a stack overflow error.

Original References

The vulnerability was initially reported by a security researcher who discovered the issue in Elasticsearch and responsibly disclosed it to the software vendor. The details of the vulnerability and its potential impact can be found in the following reference links:

- NVD - Detail: CVE-2024-52981
- Elastic's GitHub Issue _(Replace xxxxx with the actual issue number once it's available)_

Mitigations

As a temporary workaround, Elasticsearch users can limit the complexity of the WKT input strings they process. However, this may not be feasible or efficient for environments with diverse and complex data needs.

The long-term solution is to wait for an official fix from Elasticsearch developers, which will likely be released in a future version of the software. In the meantime, it is highly recommended to stay up-to-date with Elasticsearch's releases and announcement channels for updates and be prepared to apply patches as they become available.

Conclusion

In summary, CVE-2024-52981 is a critical stack overflow vulnerability affecting Elasticsearch's processing of WKT formatted strings with nested GeometryCollection objects. The vulnerability can be exploited to cause a Denial of Service attack, service disruptions, or possibly arbitrary code execution. Currently, the best course of action is to be vigilant and monitor Elasticsearch for any patch releases addressing this issue and apply them as soon as possible.

Timeline

Published on: 04/08/2025 17:15:35 UTC
Last modified on: 04/08/2025 18:13:53 UTC