CVE-2015-1555 in Zend Framework
Summary
by MITRE
Zend/Session/SessionManager in Zend Framework 2.2.x before 2.2.9, 2.3.x before 2.3.4 allows remote attackers to create valid sessions without using session validators.
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Analysis
by VulDB Data Team • 11/04/2019
The vulnerability identified as CVE-2015-1555 represents a critical session management flaw within the Zend Framework 2.x series, specifically affecting versions prior to 2.2.9 and 2.3.4. This issue resides within the Zend/Session/SessionManager component which is responsible for handling session creation and validation processes in web applications built on this framework. The vulnerability stems from insufficient session validation mechanisms that allow unauthorized parties to create seemingly legitimate sessions without proper authentication or validation checks.
The technical flaw manifests when the session manager fails to properly validate session identifiers against established security parameters. Attackers can exploit this weakness by crafting session tokens that bypass the normal validation procedures implemented by the framework. This occurs because the system does not adequately verify session integrity or authenticity before accepting session data as valid. The vulnerability essentially creates a backdoor where session creation becomes possible without the required security checks that would normally prevent unauthorized access to protected application resources.
From an operational impact perspective, this vulnerability enables remote attackers to establish sessions that appear legitimate to the application, potentially allowing them to access protected resources, perform unauthorized actions, or escalate privileges within the affected system. The attack vector is particularly concerning because it operates entirely at the session management layer, meaning that even if application-level security measures are robust, the underlying session handling mechanism can be subverted. This creates a scenario where attackers can gain persistent access to user sessions without needing to compromise user credentials or bypass other security controls.
The vulnerability maps directly to CWE-613, which addresses "Insufficient Session Expiration" and related session management weaknesses, and aligns with ATT&CK technique T1563.002 for "Access Token Manipulation" as it allows attackers to manipulate session tokens to gain unauthorized access. Organizations using affected versions of Zend Framework face significant risk of session hijacking, unauthorized data access, and potential system compromise. The impact extends beyond simple unauthorized access to include potential data breaches, privilege escalation, and the possibility of using established sessions to move laterally within network environments.
Mitigation strategies should focus on immediate patching to versions 2.2.9 or 2.3.4, which contain the necessary fixes for session validation. Security teams should also implement additional monitoring for unusual session creation patterns and consider implementing more robust session validation mechanisms. Organizations should conduct comprehensive security assessments of their Zend Framework applications to identify any potential exploitation attempts and ensure that all session management components are properly configured with appropriate security controls. The remediation process should include verifying that session validators are correctly implemented and that all session data undergoes proper integrity checks before being accepted as valid by the application.