CVE-2013-1656 in Spree
Summary
by MITRE
Spree Commerce 1.0.x through 1.3.2 allow remote authenticated administrators to instantiate arbitrary Ruby objects and execute arbitrary commands via the (1) payment_method parameter to core/app/controllers/spree/admin/payment_methods_controller.rb; and the (2) promotion_action parameter to promotion_actions_controller.rb, (3) promotion_rule parameter to promotion_rules_controller.rb, and (4) calculator_type parameter to promotions_controller.rb in promo/app/controllers/spree/admin/, related to unsafe use of the constantize function.
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Analysis
by VulDB Data Team • 02/25/2019
This vulnerability exists in Spree Commerce versions 1.0.x through 1.3.2 and represents a critical remote code execution flaw that affects authenticated administrator users. The vulnerability stems from the unsafe use of Ruby's constantize function within multiple admin controllers, specifically in payment_methods_controller.rb, promotion_actions_controller.rb, promotion_rules_controller.rb, and promotions_controller.rb. When administrators interact with these controllers, the application fails to properly validate or sanitize user input before passing it to the constantize method, which interprets strings as class names and attempts to instantiate them. This creates a path for attackers to execute arbitrary Ruby code by manipulating parameters that control object instantiation, effectively bypassing normal security boundaries.
The technical flaw manifests through four distinct attack vectors that all leverage the same underlying vulnerability pattern. The payment_method parameter in the payment methods controller allows attackers to specify arbitrary class names that get converted to actual Ruby classes through constantize. Similarly, the promotion_action parameter in promotion_actions_controller.rb, promotion_rule parameter in promotion_rules_controller.rb, and calculator_type parameter in promotions_controller.rb all suffer from identical weaknesses. These parameters are directly passed to constantize without proper input validation, enabling attackers to inject malicious class names that result in arbitrary command execution. The vulnerability is classified as a code injection issue that aligns with CWE-94, which describes the improper execution of code due to unsafe use of dynamic code execution mechanisms.
The operational impact of this vulnerability is severe and potentially devastating for affected systems. An authenticated attacker with administrator privileges can execute arbitrary commands on the server, potentially leading to full system compromise, data exfiltration, or persistent backdoor installation. The attack requires only administrative credentials, which makes it particularly dangerous as it can be exploited by insiders or through credential compromise. The vulnerability affects the core administrative functionality of Spree Commerce, making it difficult to contain and remediate without complete system reinstallation or patching. This represents a critical security weakness that can lead to complete system takeover and unauthorized access to sensitive customer data, payment information, and business-critical resources.
Mitigation strategies should focus on immediate patching of affected versions, as this vulnerability has been addressed in subsequent releases of Spree Commerce. Organizations should implement strict input validation and sanitization for all parameters that are processed through constantize or similar methods, ensuring that only predefined, safe class names are accepted. The use of allowlists for valid parameter values instead of blacklists provides a more secure approach to handling dynamic class instantiation. Additionally, implementing proper privilege separation and monitoring administrative activities can help detect unauthorized exploitation attempts. This vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, and T1078.004 for valid accounts, as it leverages legitimate administrative privileges to execute malicious code. Regular security assessments and input validation reviews should be conducted to prevent similar issues in other applications that utilize dynamic code execution features.