CVE-2022-25883: Uncovering a ReDoS Vulnerability in Semver Package Before v7.5.2

A newly disclosed vulnerability, designated CVE-2022-25883, has been discovered in versions of the semver package prior to version 7.5.2. This vulnerability can lead to a particular type of attack called Regular Expression Denial of Service (ReDoS) when untrusted user data is provided as a range to the "new Range" function in semver. In this blog post, we will explore the technical details of this vulnerability, examine how it can be exploited, and provide recommendations for mitigating the potential risks.

Vulnerability Details

CVE-2022-25883 affects the semver package utilized by numerous projects to manage and compare version numbers in a standardized format, following semantic versioning rules. The vulnerability surfaces when the package processes untrusted user input as a range via the function new Range.

The semver package relies on regular expressions for parsing and validating ranges. However, the regular expressions used to parse the range input are vulnerable to ReDoS attacks. ReDoS is a type of denial-of-service attack that aims to exhaust the resources of a system by engaging it with exhaustive regex backtracking, causing the target application to become unresponsive or crash.

Exploit Details

An attacker can exploit CVE-2022-25883 by feeding the system specially-crafted input strings that trigger the regex backtracking. These strings intentionally contain an excessive number of characters or repeated patterns, causing the regex engine to work exponentially harder with each additional character.

Here's a code snippet demonstrating the vulnerability

const { Range } = require('semver');

// Attacker provides the following malicious string
const maliciousInput = '1..||||||...';

// Application consumes the untrusted user data as a range
const range = new Range(maliciousInput);

// The system is now stuck processing the input, causing a denial of service

Links to original references

1. CVE-2022-25883 - GitHub Advisory Database
2. Semver Package Documentation
3. National Vulnerability Database - CVE-2022-25883

Mitigations

To protect against this vulnerability, users are recommended to upgrade their semver packages to version 7.5.2 or later. The developers of the semver package have provided a fix in the latest release, which addresses the regex vulnerability and mitigates the risk of ReDoS attacks.

For applications that do not leverage the semver package directly, developers should review their dependencies for vulnerable versions of semver and update them accordingly.

Conclusion

CVE-2022-25883 is a critical vulnerability that can lead to ReDoS attacks in applications using affected versions of the semver package. Developers must act quickly to ensure their applications are secure and not exposed to this risk. By upgrading to the latest version of the semver package, developers can address this vulnerability and protect their systems from potential attacks.

Timeline

Published on: 06/21/2023 05:15:00 UTC
Last modified on: 07/12/2023 00:53:00 UTC