Platform
ruby
Component
thin
Fixed in
1.2.4
CVE-2009-3287 describes an IP address spoofing vulnerability in the Thin web server. This flaw allows attackers to manipulate the X-Forwarded-For header, leading to inaccurate client IP address identification and potentially enabling malicious actors to hide their activities. The vulnerability affects versions of Thin up to and including 1.2.3, and a fix is available in version 1.2.4.
The primary impact of CVE-2009-3287 is the ability for an attacker to spoof the client's IP address. This can be leveraged for various malicious purposes, including bypassing access controls that rely on IP address filtering, masking the origin of attacks, and potentially facilitating unauthorized access to internal resources. An attacker could, for example, impersonate a trusted client to gain access to sensitive data or perform actions on behalf of that client. The blast radius extends to any system relying on the Thin web server for reverse proxying or load balancing, as the spoofed IP address could be propagated downstream.
CVE-2009-3287 was publicly disclosed in 2009, but its relevance has been re-evaluated in 2017. While no active exploitation campaigns are currently known, the vulnerability's simplicity makes it a potential target. It is not listed on the CISA KEV catalog. Public proof-of-concept exploits are available, demonstrating the ease with which the vulnerability can be exploited.
Exploit Status
EPSS
0.48% (65% percentile)
The recommended mitigation for CVE-2009-3287 is to upgrade to version 1.2.4 of the Thin web server. If upgrading is not immediately feasible, consider implementing a Web Application Firewall (WAF) or reverse proxy with strict X-Forwarded-For header validation. Configure the WAF to reject requests with malformed or suspicious X-Forwarded-For headers. Additionally, review and strengthen any access control mechanisms that rely on client IP addresses. After upgrading, verify the fix by attempting to send a request with a modified X-Forwarded-For header and confirming that the server rejects it or logs the attempt.
No official patch available. Check for workarounds or monitor for updates.
Vulnerability analysis and critical alerts directly to your inbox.
CVE-2009-3287 is a vulnerability in Thin web server versions up to 1.2.3 that allows attackers to spoof client IP addresses by manipulating the X-Forwarded-For header, potentially hiding malicious activity.
You are affected if you are running Thin web server version 1.2.3 or earlier. Upgrade to version 1.2.4 to mitigate the risk.
The recommended fix is to upgrade to version 1.2.4 of the Thin web server. If upgrading is not possible, implement a WAF with X-Forwarded-For header validation.
While no active campaigns are currently known, the vulnerability's simplicity makes it a potential target. Public proof-of-concept exploits exist.
Refer to the original advisory and related discussions on security mailing lists and vulnerability databases for details.
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