CVE-2017-16023 in Decamelize
Summary
by MITRE
Decamelize is used to convert a dash/dot/underscore/space separated string to camelCase. Decamelize 1.1.0 through 1.1.1 uses regular expressions to evaluate a string and takes unescaped separator values, which can be used to create a denial of service attack.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 02/14/2020
The vulnerability identified as CVE-2017-16023 affects the decamelize npm package version 1.1.0 through 1.1.1, which is commonly used in JavaScript applications for converting strings from dash, dot, underscore, or space separated formats to camelCase notation. This seemingly innocuous utility function becomes a critical security concern due to its improper handling of regular expression patterns within user-provided input strings. The flaw resides in the package's inability to properly escape special characters that have meaning within regular expression syntax when these characters appear as part of the input string being processed.
The technical implementation of this vulnerability stems from the decamelize library's use of regular expressions without adequate input sanitization or escaping mechanisms. When the package processes strings containing special regex characters such as dots, asterisks, plus signs, or other metacharacters, these characters are interpreted by the regular expression engine rather than treated as literal string content. This misinterpretation creates a path for malicious input to disrupt the regular expression evaluation process, leading to excessive CPU consumption and potential denial of service conditions. The vulnerability operates under CWE-1321, which classifies issues related to improper handling of regular expressions and input validation in string processing functions.
The operational impact of this vulnerability extends beyond simple denial of service scenarios and represents a significant threat to application stability and availability. An attacker can craft malicious input strings containing specially designed sequences of characters that cause the regular expression engine to enter into computationally expensive operations or even infinite loops. This behavior can be exploited in applications where user input is processed through the decamelize function, potentially allowing attackers to consume excessive system resources and render services unavailable to legitimate users. The attack vector aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion.
Organizations utilizing affected versions of the decamelize package should immediately implement mitigations including updating to version 1.1.2 or later, which addresses the regular expression escaping issue. Additionally, input validation should be implemented at application boundaries to sanitize any strings that will be processed by the decamelize function. The vulnerability demonstrates the importance of proper input sanitization and regular expression handling in common utility libraries, as these components often form the foundation of larger applications and can serve as attack vectors when not properly secured against malicious input patterns. Security teams should conduct comprehensive audits of their dependency trees to identify other potentially vulnerable packages that may exhibit similar issues with regular expression processing and input handling.