Platform
ruby
Component
actionpack
Fixed in
4.2.5.1
CVE-2015-7581 is a denial-of-service (DoS) vulnerability discovered in Action Pack, a core component of the Ruby on Rails web application framework. This vulnerability allows remote attackers to cause excessive caching and memory consumption, potentially leading to application instability and service disruption. It impacts Ruby on Rails versions 4.x prior to 4.2.5.1 and versions of 5.x before 5.0.0.beta1.1. A fix has been released in Rails 4.2.5.1.
The vulnerability stems from how Action Pack handles wildcard controller routes. An attacker can craft requests that exploit this mechanism, causing the routing layer to generate an excessive number of cached routes. This leads to a rapid increase in memory usage, potentially exhausting server resources and causing the application to become unresponsive. The impact can range from temporary slowdowns to complete service outages. The attack doesn't directly expose sensitive data, but the resulting DoS can prevent legitimate users from accessing the application and disrupt business operations. This vulnerability shares similarities with other routing-related DoS attacks, highlighting the importance of carefully configuring routing rules to prevent unintended consequences.
CVE-2015-7581 was publicly disclosed in 2017. While no active exploitation campaigns have been definitively linked to this specific CVE, DoS vulnerabilities are frequently targeted. The vulnerability is not currently listed on CISA's KEV catalog. Public proof-of-concept exploits are available, demonstrating the ease with which the vulnerability can be triggered. The relatively simple nature of the exploit increases the likelihood of its adoption by malicious actors.
Exploit Status
EPSS
7.11% (91% percentile)
CVSS Vector
The primary mitigation for CVE-2015-7581 is to upgrade to a patched version of Ruby on Rails. Specifically, upgrade to version 4.2.5.1 or later for 4.x series, or 5.0.0.beta1.1 or later for 5.x series. If an immediate upgrade is not feasible, consider implementing temporary workarounds such as limiting the number of cached routes or implementing rate limiting on requests that utilize wildcard routes. While not a complete solution, a Web Application Firewall (WAF) could be configured to block requests exhibiting patterns associated with this exploitation technique. Monitor server resource utilization (CPU, memory) for unusual spikes, which could indicate an ongoing attack.
No official patch available. Check for workarounds or monitor for updates.
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CVE-2015-7581 is a denial-of-service vulnerability in Ruby on Rails Action Pack, allowing attackers to cause memory exhaustion through wildcard routes.
You are affected if you are using Ruby on Rails versions 4.x before 4.2.5.1 or 5.x before 5.0.0.beta1.1.
Upgrade to Ruby on Rails 4.2.5.1 or later for 4.x, or 5.0.0.beta1.1 or later for 5.x. Consider temporary workarounds if immediate upgrade is not possible.
While no confirmed active campaigns are known, DoS vulnerabilities are frequently targeted, and public exploits exist.
Refer to the official Ruby on Rails security advisories: https://github.com/rails/rails/security/advisories
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