CVE-2009-3476 in Shibboleth-sp
Summary
by MITRE
Buffer overflow in OpenSAML before 1.1.3 as used in Internet2 Shibboleth Service Provider software 1.3.x before 1.3.4, and XMLTooling before 1.2.2 as used in Internet2 Shibboleth Service Provider software 2.x before 2.2.1, allows remote attackers to cause a denial of service and possibly execute arbitrary code via a malformed encoded URL.
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Analysis
by VulDB Data Team • 01/22/2019
The vulnerability identified as CVE-2009-3476 represents a critical buffer overflow flaw affecting OpenSAML software components that were widely deployed within Internet2 Shibboleth Service Provider implementations. This issue specifically impacts versions prior to 1.1.3 of OpenSAML and corresponding versions of XMLTooling that were utilized in Shibboleth Service Provider software versions 1.3.x before 1.3.4 and 2.x before 2.2.1. The flaw resides in the handling of encoded URL parameters within the SAML authentication framework, creating a pathway for malicious actors to exploit the system through carefully crafted malformed inputs.
The technical nature of this vulnerability stems from inadequate input validation and boundary checking within the OpenSAML library's URL decoding routines. When the software processes malformed encoded URLs, the buffer overflow occurs during the parsing of URL-encoded data, particularly affecting the handling of special characters and encoded sequences that exceed predetermined buffer limits. This condition manifests as a classic stack-based buffer overflow, where attacker-controlled data overwrites adjacent memory locations, potentially corrupting program execution flow and creating opportunities for arbitrary code execution. The vulnerability operates at the application layer and requires no special privileges to exploit, making it particularly dangerous in networked environments where SAML-based authentication services are exposed to untrusted inputs.
The operational impact of this vulnerability extends beyond simple denial of service to encompass potential system compromise and unauthorized access to protected resources. Remote attackers can leverage this flaw to cause service interruptions by triggering application crashes or restarts, effectively creating a denial of service condition that disrupts legitimate authentication flows. More critically, the buffer overflow may enable remote code execution when attackers can control the overflowed memory locations, potentially allowing them to execute malicious payloads with the privileges of the affected service process. This represents a significant threat to identity and access management systems that rely on Shibboleth for authentication, as successful exploitation could lead to unauthorized access to protected applications and data repositories.
Organizations utilizing affected versions of Shibboleth Service Provider software face substantial risk from this vulnerability, particularly those with exposed authentication endpoints or systems that process untrusted SAML assertions. The attack surface includes any web application or service that relies on Shibboleth for single sign-on functionality, making the impact widespread across educational and enterprise environments that depend on federated identity solutions. Security practitioners should note that this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and represents a common entry point for attackers seeking to escalate privileges or establish persistent access within targeted environments.
Mitigation strategies for CVE-2009-3476 require immediate patching of affected software components to versions that include proper input validation and buffer boundary checking. Organizations should prioritize updating OpenSAML to version 1.1.3 or later, along with corresponding updates to XMLTooling components to 1.2.2 or newer. Additionally, network administrators should implement defensive measures such as input validation at proxy layers, rate limiting for authentication endpoints, and monitoring for suspicious URL patterns that might indicate exploitation attempts. The remediation process should include comprehensive testing of updated systems to ensure that the patch does not introduce compatibility issues with existing SAML configurations and authentication workflows. Security teams should also consider implementing intrusion detection systems capable of identifying patterns associated with buffer overflow exploitation attempts and establish incident response procedures to address potential exploitation attempts.