CVE-2017-15928 in Ox Gem
Summary
by MITRE
In the Ox gem 2.8.0 for Ruby, the process crashes with a segmentation fault when a crafted input is supplied to parse_obj. NOTE: the vendor has stated "Ox should handle the error more gracefully" but has not confirmed a security implication.
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Analysis
by VulDB Data Team • 01/05/2023
The vulnerability identified as CVE-2017-15928 affects the Ox gem version 2.8.0 for Ruby, representing a critical stability issue that manifests through a segmentation fault during XML parsing operations. This flaw specifically occurs when the parse_obj method processes crafted input data, causing the entire application process to crash unexpectedly. The vulnerability demonstrates a classic buffer over-read or memory corruption issue where malformed input triggers undefined behavior in the underlying C extension code that powers the Ox gem's high-performance XML parsing capabilities.
The technical implementation of this vulnerability stems from insufficient input validation within the Ox gem's XML parser, which fails to properly handle malformed or specially crafted XML structures. When the parse_obj function encounters unexpected input patterns, particularly those designed to exploit memory access boundaries, the parser's internal state becomes corrupted leading to a segmentation fault. This type of vulnerability aligns with CWE-121, which covers stack-based buffer overflow conditions, and CWE-125, which addresses out-of-bounds read errors. The segmentation fault represents a denial-of-service condition that can be exploited by attackers to disrupt service availability, though the vendor has not confirmed direct security implications beyond the crash behavior.
From an operational perspective, this vulnerability presents significant risks to applications that rely on the Ox gem for XML processing, particularly in production environments where stability and uptime are critical. The segmentation fault can occur during routine XML parsing operations, potentially affecting web applications, API services, or any system that processes external XML data. Attackers could leverage this vulnerability to repeatedly crash services, leading to service disruption and potential resource exhaustion attacks. The vulnerability impacts the broader Ruby ecosystem where Ox is commonly used for high-performance XML processing, making it a concern for enterprise applications that depend on reliable XML parsing functionality.
Security practitioners should implement immediate mitigations including upgrading to patched versions of the Ox gem, implementing input validation layers, and monitoring for crash patterns in affected applications. The recommended approach involves updating to versions that properly handle error conditions without crashing, as the vendor has acknowledged the need for more graceful error handling rather than abrupt process termination. Organizations should also consider implementing application-level defenses such as input sanitization, rate limiting, and robust error handling mechanisms to prevent exploitation of this vulnerability. Additionally, this issue aligns with ATT&CK technique T1499.004, which covers network denial of service, and T1566.001, covering spearphishing attachments, as attackers could potentially craft malicious XML payloads to exploit this vulnerability in targeted attacks.