CVE-2015-4411 in bson-ruby
Summary
by MITRE
The Moped::BSON::ObjecId.legal? method in mongodb/bson-ruby before 3.0.4 as used in rubygem-moped allows remote attackers to cause a denial of service (worker resource consumption) via a crafted string. NOTE: This issue is due to an incomplete fix to CVE-2015-4410.
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Analysis
by VulDB Data Team • 11/24/2024
The vulnerability described in CVE-2015-4411 represents a denial of service weakness in the mongodb/bson-ruby library version 3.0.3 and earlier, specifically within the Moped::BSON::ObjectId.legal? method. This issue arises from an incomplete remediation of a previous vulnerability CVE-2015-4410, creating a persistent security gap that allows remote attackers to exploit worker resource consumption patterns. The flaw manifests when the library processes crafted string inputs that trigger excessive computational overhead during validation operations.
The technical implementation of this vulnerability stems from inadequate input validation within the ObjectId.legal? method which is designed to verify the legitimacy of BSON ObjectIds. When attackers provide malformed or specially crafted strings, the method enters into resource-intensive processing loops that consume excessive CPU cycles and memory resources. This behavior aligns with CWE-400, which classifies improper resource management as a significant vulnerability category, particularly in systems where resource consumption directly impacts availability. The method's failure to properly handle edge cases in string parsing creates a condition where computational resources become saturated through repeated or nested validation operations.
From an operational perspective, this vulnerability enables attackers to perform denial of service attacks against systems running affected versions of the mongodb/bson-ruby library. The resource consumption patterns can lead to complete worker thread exhaustion, causing application instability and potential system crashes. Attackers can exploit this weakness by sending malicious strings to endpoints that utilize the ObjectId.legal? method, particularly in applications that process user-provided data through MongoDB BSON serialization. This vulnerability particularly impacts web applications, API services, and backend systems that rely on rubygem-moped for MongoDB connectivity, creating a significant availability risk that can affect business continuity and service delivery.
The remediation for CVE-2015-4411 requires upgrading to mongodb/bson-ruby version 3.0.4 or later, which implements proper input validation and resource management within the ObjectId.legal? method. Security practitioners should also implement input sanitization at application layers to reduce the attack surface, particularly in systems that cannot immediately upgrade. Organizations should monitor for similar patterns in other BSON parsing methods and ensure comprehensive testing of input validation routines. This vulnerability demonstrates the importance of complete vulnerability remediation and the potential for partial fixes to create new attack vectors. The issue relates to ATT&CK technique T1499.004, which covers network denial of service attacks, and emphasizes the need for robust resource management practices in database connectivity libraries.