CVE-2014-9490 in raven-ruby
Summary
by MITRE
The numtok function in lib/raven/okjson.rb in the raven-ruby gem before 0.12.2 for Ruby allows remote attackers to cause a denial of service via a large exponent value in a scientific number.
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Analysis
by VulDB Data Team • 04/11/2022
The CVE-2014-9490 vulnerability affects the raven-ruby gem version 0.12.1 and earlier, specifically targeting the numtok function within the lib/raven/okjson.rb file. This flaw represents a denial of service vulnerability that can be exploited by remote attackers through manipulation of scientific notation numbers containing excessively large exponent values. The vulnerability stems from insufficient input validation and sanitization within the JSON parsing component of the gem, which is commonly used for error reporting and logging in ruby applications.
The technical implementation of this vulnerability resides in the numtok function's handling of scientific notation numbers where it fails to properly validate exponent values before processing them. When a maliciously crafted JSON payload contains a scientific number with an extremely large exponent, the parsing routine attempts to compute the resulting value, leading to excessive resource consumption and ultimately causing the application to become unresponsive or crash. This behavior aligns with CWE-400, which categorizes the vulnerability as an uncontrolled resource consumption issue, specifically manifesting as a denial of service condition.
The operational impact of this vulnerability extends beyond simple service disruption, as it can be leveraged by attackers to perform resource exhaustion attacks against ruby applications that utilize the raven-ruby gem for error reporting. Applications using this gem for logging error events, particularly those that process untrusted JSON input from users or external sources, become vulnerable to this attack vector. The vulnerability is particularly concerning in web applications where JSON payloads are commonly received from clients, making it a significant risk for applications that do not properly sanitize input data before processing it through the gem's JSON parsing functionality.
Mitigation strategies for this vulnerability require immediate upgrade of the raven-ruby gem to version 0.12.2 or later, which includes proper validation of exponent values during JSON parsing. Additionally, organizations should implement input validation at the application level to sanitize JSON data before it reaches the gem's parsing functions, as outlined in the ATT&CK technique T1059.101 for input validation and sanitization. Network-level protections such as rate limiting and payload size restrictions can provide additional defense-in-depth measures, while monitoring and logging should be implemented to detect potential exploitation attempts. The vulnerability demonstrates the importance of proper resource management in parsing libraries and highlights the necessity of comprehensive testing for edge cases in mathematical operations within security-critical components.