CVE-2018-19595 in PbootCMS
Summary
by MITRE
PbootCMS V1.3.1 build 2018-11-14 allows remote attackers to execute arbitrary code via use of "eval" with mixed case, as demonstrated by an index.php/list/5/?current={pboot:if(evAl($_GET[a]))}1{/pboot:if}&a=phpinfo(); URI, because of an incorrect apps\home\controller\ParserController.php parserIfLabel protection mechanism.
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Analysis
by VulDB Data Team • 04/15/2020
CVE-2018-19595 represents a critical remote code execution vulnerability in PbootCMS version 1.3.1 that exploits a flawed input validation mechanism within the template processing system. This vulnerability stems from an inadequate sanitization of user-supplied data within the template engine, specifically in the apps\home directory where the template parsing logic fails to properly validate or escape dynamic content. The flaw manifests when the system processes template tags containing the eval function with mixed case variations, allowing attackers to inject malicious PHP code that gets executed within the web application context. The vulnerability is particularly dangerous because it leverages the legitimate template processing functionality to bypass normal security controls, making it difficult to detect through conventional means.
The technical exploitation occurs through a carefully crafted URI parameter that passes through the template engine's parsing mechanism. In the demonstrated attack vector, the attacker crafts a URL with a template tag containing mixed case eval function combined with a phpinfo() command. The template engine processes this input without proper validation, executing the phpinfo() command and revealing sensitive system information to the attacker. This represents a classic case of template injection vulnerability where dynamic content is not properly sanitized before being processed, creating an execution path that allows arbitrary code execution. The vulnerability is categorized under CWE-94 as "Improper Control of Generation of Code ('Code Injection')" and aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: Python" and T1059.008 for "Command and Scripting Interpreter: PowerShell" through the PHP execution pathway.
The operational impact of this vulnerability extends far beyond simple information disclosure, as successful exploitation provides attackers with full command execution capabilities on the affected server. An attacker can leverage this vulnerability to establish persistent access, deploy backdoors, exfiltrate sensitive data, or use the compromised system as a launch point for further attacks within the network. The vulnerability affects not just the web application itself but potentially the entire server infrastructure, as the execution occurs with the privileges of the web server process. Organizations using PbootCMS v1.3.1 are at significant risk of data breaches, system compromise, and potential regulatory violations depending on the nature of the data handled by the affected applications. The attack requires minimal sophistication and can be automated, making it particularly dangerous for widespread exploitation.
Mitigation strategies for CVE-2018-19595 focus on immediate patching and implementation of robust input validation controls. The primary recommendation is to upgrade to a patched version of PbootCMS that addresses the template injection vulnerability and implements proper sanitization of user inputs. Organizations should also implement web application firewalls with rules specifically designed to detect and block template injection attempts, particularly those involving eval functions or similar code execution mechanisms. Additional defensive measures include restricting web server privileges, implementing proper input validation at multiple layers of the application architecture, and conducting regular security assessments of template processing components. Network segmentation and monitoring solutions should be deployed to detect anomalous execution patterns that might indicate exploitation attempts. Organizations should also consider implementing automated patch management systems to ensure timely remediation of similar vulnerabilities in the future, as this type of vulnerability often indicates broader issues with input validation and code execution controls that may affect other components of the application stack.