CVE-2013-1397 in Symfony
Summary
by MITRE
Symfony 2.0.x before 2.0.22, 2.1.x before 2.1.7, and 2.2.x remote attackers to execute arbitrary PHP code via a serialized PHP object to the (1) Yaml::parse or (2) Yaml\Parser::parse function, a different vulnerability than CVE-2013-1348.
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Analysis
by VulDB Data Team • 06/14/2018
The vulnerability identified as CVE-2013-1397 represents a critical remote code execution flaw affecting the Symfony web application framework version 2.0.x before 2.0.22, 2.1.x before 2.1.7, and 2.2.x. This vulnerability specifically targets the YAML parsing functionality within the framework, creating a dangerous attack vector that allows remote adversaries to execute arbitrary PHP code on affected systems. The flaw resides in the Yaml::parse and Yaml\Parser::parse functions which are commonly used for processing YAML configuration files and data structures within Symfony applications. When these functions process untrusted YAML input containing serialized PHP objects, they inadvertently deserialize and execute malicious code, bypassing normal security controls and access restrictions that typically protect server-side applications from unauthorized code execution.
The technical nature of this vulnerability aligns with CWE-502, which describes "Deserialization of Untrusted Data" as a critical weakness in software applications. This classification indicates that the vulnerability stems from the framework's failure to properly validate and sanitize serialized data before deserializing it, creating an opportunity for attackers to inject malicious payloads that execute within the application's context. The attack methodology involves sending specially crafted YAML data containing serialized PHP objects to the vulnerable functions, which then automatically deserialize and execute the embedded code without proper security checks. This type of vulnerability falls under the ATT&CK technique T1059.007, which encompasses "Command and Scripting Interpreter: Python" and similar execution methods, as the deserialization process effectively allows attackers to execute arbitrary commands through the PHP interpreter. The vulnerability demonstrates a classic path traversal and code injection pattern where untrusted input flows directly into a deserialization mechanism, bypassing standard input validation and sanitization controls that would normally prevent such attacks.
The operational impact of CVE-2013-1397 is severe and potentially devastating for organizations running affected Symfony applications. Remote attackers can leverage this vulnerability to gain complete control over affected servers, potentially leading to data breaches, system compromise, and full network infiltration. The vulnerability affects a wide range of Symfony applications that utilize YAML parsing functionality, making it particularly dangerous as it could impact numerous web applications across different industries and use cases. Organizations may experience unauthorized access to sensitive data, modification of application behavior, and potential establishment of persistent backdoors on compromised systems. The attack surface extends beyond individual applications to potentially affect entire server infrastructures, especially when multiple applications share common dependencies or when applications are deployed in environments where proper input validation and security controls are not implemented. Additionally, the vulnerability's impact is compounded by the fact that YAML parsing is a common operation in web applications, making it likely that many applications would be affected without proper patching or mitigation measures.
Mitigation strategies for CVE-2013-1397 require immediate action to address the root cause of the vulnerability. The most effective solution involves upgrading affected Symfony installations to versions 2.0.22, 2.1.7, or 2.2.x, which contain patches specifically designed to prevent the deserialization of untrusted data in the YAML parsing functions. Organizations should also implement comprehensive input validation and sanitization measures, ensuring that any YAML data processed by the application undergoes strict validation before deserialization occurs. Security teams should consider implementing web application firewalls and intrusion detection systems that can identify and block suspicious YAML parsing patterns and serialized object attempts. Additional protective measures include restricting file permissions on YAML configuration files, implementing proper access controls for YAML parsing endpoints, and conducting thorough security assessments to identify other potential deserialization vulnerabilities within the application stack. Organizations should also establish monitoring procedures to detect unauthorized code execution attempts and maintain up-to-date security patches for all framework components to prevent similar vulnerabilities from emerging in the future.