CVE-2014-8350 in Smarty
Summary
by MITRE
Smarty before 3.1.21 allows remote attackers to bypass the secure mode restrictions and execute arbitrary PHP code as demonstrated by "{literal}<{/literal}script language=php>" in a template.
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Analysis
by VulDB Data Team • 12/09/2024
The vulnerability identified as CVE-2014-8350 affects the Smarty template engine version 3.1.20 and earlier, representing a critical security flaw that undermines the engine's secure mode protections. This vulnerability resides within the template parsing mechanism and specifically targets the handling of literal tags that are intended to prevent PHP code execution within template files. The issue allows malicious actors to circumvent the secure mode restrictions that are designed to prevent arbitrary code execution, thereby creating a significant attack vector for remote code execution.
The technical flaw manifests in the improper handling of the {literal} tag combination within Smarty templates, where the parser fails to properly sanitize or validate content that appears between these tags when they are used in conjunction with script elements. When an attacker crafts a template containing the sequence "{literal}<{/literal}script language=php>", the Smarty engine processes this construct in a manner that allows PHP code execution despite the secure mode being enabled. This vulnerability operates at the template compilation level, where the engine interprets the literal tag combination as a legitimate means to inject executable code while bypassing the intended security boundaries.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with full control over the affected system where the Smarty engine is deployed. Remote attackers can leverage this flaw to execute arbitrary PHP code, potentially leading to complete system compromise, data exfiltration, or service disruption. The vulnerability is particularly dangerous because it can be exploited through template injection attacks where users can manipulate template content, and the secure mode protections are designed to prevent exactly this type of scenario. This makes the vulnerability especially concerning for web applications that utilize Smarty for template rendering and may accept user-supplied template content.
Mitigation strategies for CVE-2014-8350 involve immediate upgrading to Smarty version 3.1.21 or later, which contains the necessary patches to address the insecure parsing behavior. Organizations should also implement strict template validation mechanisms that prevent user input from being processed as executable template content, and employ proper input sanitization techniques for any template data. The vulnerability aligns with CWE-94, which describes improper control of generation of code, and relates to ATT&CK technique T1190, which covers exploit public-facing application. Additionally, implementing web application firewalls and monitoring for suspicious template content patterns can help detect and prevent exploitation attempts, while regular security audits should verify that secure mode configurations are properly enforced across all Smarty installations.