CVE-2015-7576: Timing Attack in Ruby on Rails Actionpack
Platform
ruby
Component
actionpack
Fixed in
3.2.22.1
CVE-2015-7576 describes a timing attack vulnerability within the HTTP Basic Authentication implementation of Ruby on Rails' Action Controller. This flaw allows a remote attacker to potentially bypass authentication by analyzing the time taken to verify credentials. The vulnerability affects versions of Actionpack up to and including 3.2.9.rc3, with a fix available in version 3.2.22.1.
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Impact and Attack Scenarios
The primary impact of CVE-2015-7576 is the potential for unauthorized access to protected resources within a Ruby on Rails application. An attacker can exploit this timing vulnerability to deduce valid credentials by repeatedly attempting authentication and measuring the response times. While the CVSS score is LOW, successful exploitation could lead to complete compromise of the application and its data, particularly if sensitive information is accessible via Basic Authentication. This vulnerability shares similarities with other timing attacks targeting authentication mechanisms, highlighting the importance of constant-time algorithms in security-critical code.
Exploitation Context
CVE-2015-7576 was published in 2017. There is no indication of active exploitation campaigns targeting this vulnerability. No public Proof-of-Concept (POC) exploits have been widely reported. The EPSS score is likely low, reflecting the difficulty and specialized knowledge required to successfully exploit this timing attack.
Threat Intelligence
Exploit Status
EPSS
1.57% (81% percentile)
CVSS Vector
What do these metrics mean?
- Attack Vector
- Network — remotely exploitable over the internet. No physical or local access required. Widest attack surface.
- Attack Complexity
- High — requires a race condition, non-default configuration, or specific circumstances. Harder to exploit reliably.
- Privileges Required
- None — unauthenticated. No login or credentials needed to exploit.
- User Interaction
- None — attack is automatic and silent. Victim does nothing: no click, no file open.
- Scope
- Unchanged — impact is limited to the vulnerable component itself.
- Confidentiality
- Low — partial or indirect data access. Attacker gains limited information.
- Integrity
- None — no integrity impact. Attacker cannot modify data.
- Availability
- None — no availability impact. Service remains fully operational.
Affected Software
Timeline
- Published
- Modified
- EPSS updated
Mitigation and Workarounds
The recommended mitigation for CVE-2015-7576 is to upgrade to Ruby on Rails version 3.2.22.1 or later. If upgrading is not immediately feasible, consider disabling HTTP Basic Authentication entirely and implementing a more robust authentication mechanism. As a temporary workaround, implement rate limiting on authentication attempts to make timing attacks more difficult. Review your application's authentication logic to ensure it adheres to constant-time principles. After upgrading, confirm the fix by attempting a timing attack against the authentication endpoint and verifying that response times remain consistent regardless of the provided credentials.
How to fix
No official patch available. Check for workarounds or monitor for updates.
Frequently asked questions
What is CVE-2015-7576 — Timing Attack in Ruby on Rails Actionpack?
CVE-2015-7576 is a vulnerability in Ruby on Rails Actionpack that allows attackers to bypass HTTP Basic Authentication by measuring timing differences during credential verification.
Am I affected by CVE-2015-7576 in Ruby on Rails Actionpack?
You are affected if your Ruby on Rails application uses Actionpack and is running a version prior to 3.2.22.1. Check your version using bundle -v.
How do I fix CVE-2015-7576 in Ruby on Rails Actionpack?
Upgrade your Ruby on Rails application to version 3.2.22.1 or later. Consider disabling Basic Authentication if upgrading is not immediately possible.
Is CVE-2015-7576 being actively exploited?
There is no public evidence of active exploitation campaigns targeting CVE-2015-7576, but the potential for exploitation remains.
Where can I find the official Ruby on Rails advisory for CVE-2015-7576?
Refer to the official Ruby on Rails security advisories: https://github.com/rails/rails/security/advisories
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