CVE-2016-0751 in macOS Server
Summary
by MITRE
actionpack/lib/action_dispatch/http/mime_type.rb in Action Pack in Ruby on Rails before 3.2.22.1, 4.0.x and 4.1.x before 4.1.14.1, 4.2.x before 4.2.5.1, and 5.x before 5.0.0.beta1.1 does not properly restrict use of the MIME type cache, which allows remote attackers to cause a denial of service (memory consumption) via a crafted HTTP Accept header.
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Analysis
by VulDB Data Team • 11/22/2022
The vulnerability identified as CVE-2016-0751 represents a critical denial of service flaw within the Ruby on Rails framework's Action Pack component. This issue specifically affects the mime_type.rb file which handles HTTP Accept header processing, creating a scenario where malicious actors can exploit the MIME type cache mechanism to consume excessive system resources. The vulnerability impacts multiple versions of Rails including 3.2.x series before 3.2.22.1, 4.0.x and 4.1.x series before 4.1.14.1, 4.2.x series before 4.2.5.1, and early 5.x releases before 5.0.0.beta1.1. The flaw stems from inadequate validation and restriction of MIME type cache usage, allowing attackers to craft specially formatted HTTP Accept headers that trigger unbounded memory consumption.
The technical implementation of this vulnerability exploits the way Rails processes HTTP Accept headers by maintaining a cache of MIME types for performance optimization. When an attacker sends a crafted Accept header containing numerous or malformed MIME type entries, the system's MIME type cache becomes populated with excessive entries without proper bounds checking. This behavior violates the principle of resource limitation and can be categorized under CWE-400, which addresses unchecked resource consumption. The vulnerability operates at the application layer and can be classified under ATT&CK technique T1499.004 for network denial of service attacks, specifically targeting resource consumption mechanisms within web applications. The flaw essentially allows attackers to cause memory exhaustion through controlled input manipulation, making it particularly dangerous in environments where memory resources are constrained.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire application availability and system stability. When exploited, the vulnerability can cause applications to consume all available memory resources, leading to process termination, system instability, and complete service unavailability. This type of attack can be particularly devastating in cloud environments or shared hosting scenarios where resource contention can affect multiple applications. The vulnerability affects web applications built on Ruby on Rails framework, which is widely used across various industries including finance, healthcare, and e-commerce sectors where application availability is critical. Organizations running affected versions of Rails may experience cascading failures, especially during high traffic periods when the memory consumption becomes more pronounced.
Mitigation strategies for CVE-2016-0751 primarily focus on upgrading to patched versions of the Ruby on Rails framework. System administrators should immediately update their Rails installations to the latest stable releases that contain the necessary patches for this vulnerability. The patched versions implement proper bounds checking on MIME type cache entries and introduce rate limiting mechanisms for Accept header processing. Additionally, organizations should implement network-level protections such as load balancer configurations that can detect and block suspicious Accept header patterns. Security monitoring should include detection of unusual memory consumption patterns and implementation of resource quotas for application processes. The vulnerability highlights the importance of input validation and resource management in web frameworks, emphasizing that even seemingly benign HTTP headers can become attack vectors when not properly constrained. Organizations should also consider implementing application firewalls or web application firewalls that can filter malicious Accept headers before they reach the application layer, providing an additional defense-in-depth mechanism against this specific attack pattern.