CVE-2023-30858 in emoji
Summary
by MITRE • 04/29/2023
The Denosaurs emoji package provides emojis for dinosaurs. Starting in version 0.1.0 and prior to version 0.3.0, the reTrimSpace regex has 2nd degree polynomial inefficiency, leading to a delayed response given a big payload. The issue has been patched in 0.3.0. As a workaround, avoid using the `replace`, `unemojify`, or `strip` functions.
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Analysis
by VulDB Data Team • 04/29/2023
The CVE-2023-30858 vulnerability affects the Denosaurs emoji package, a JavaScript/TypeScript library designed to provide dinosaur-themed emojis for applications. This package operates within the Deno ecosystem and was specifically targeted at developers seeking to incorporate dinosaur emoji functionality into their projects. The vulnerability stems from a critical performance flaw in the regular expression pattern used for text processing operations, specifically within the reTrimSpace regex implementation. The affected versions span from 0.1.0 through 0.2.x releases, with the issue being resolved in version 0.3.0. This represents a classic example of a regular expression denial of service (ReDoS) vulnerability where malicious input can cause exponential execution time increases.
The technical flaw manifests in the reTrimSpace regular expression which exhibits second-degree polynomial time complexity behavior. When processing large input payloads, particularly those containing carefully crafted malicious patterns, the regex engine experiences exponential backtracking that causes dramatic performance degradation. This vulnerability directly maps to CWE-400, which categorizes denial of service vulnerabilities resulting from inefficient regular expressions and improper input validation. The flaw is particularly dangerous because it can be exploited by attackers who craft input strings designed to trigger the problematic regex pattern, causing the application to hang or become unresponsive for extended periods. The vulnerability affects core functions including replace, unemojify, and strip operations that rely on the flawed regex pattern.
The operational impact of this vulnerability extends beyond simple performance degradation to potentially compromise entire application availability. When exploited, the delayed response behavior can cause cascading failures in applications that depend on the emoji package, particularly in scenarios involving user input processing or batch text operations. Attackers can leverage this vulnerability to perform resource exhaustion attacks, consuming CPU cycles and memory resources in a manner that degrades system performance or causes complete service unavailability. The vulnerability affects applications running in the Deno runtime environment, making it particularly concerning for web applications and server-side processing systems that might be vulnerable to such attacks. This type of vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion.
The remediation approach for CVE-2023-30858 involves upgrading to version 0.3.0 or later of the Denosaurs emoji package where the vulnerable regex pattern has been replaced with a more efficient implementation. The recommended workaround of avoiding the replace, unemojify, and strip functions provides a temporary mitigation strategy for environments where immediate upgrades are not feasible. Security practitioners should implement comprehensive monitoring for any unusual processing delays in applications using this package, particularly during high-volume input processing scenarios. The vulnerability demonstrates the importance of regular security auditing and input validation in modern software development practices, particularly when dealing with regex patterns that process untrusted user input. Organizations should also consider implementing rate limiting and input size restrictions as additional protective measures against similar vulnerabilities in other components of their software stack.