CVE-2015-0249 in Roller
Summary
by MITRE
The weblog page template in Apache Roller 5.1 through 5.1.1 allows remote authenticated users with admin privileges for a weblog to execute arbitrary Java code via crafted Velocity Text Language (aka VTL).
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Analysis
by VulDB Data Team • 10/25/2019
The vulnerability identified as CVE-2015-0249 represents a critical remote code execution flaw within Apache Roller weblogging platform versions 5.1 through 5.1.1. This security issue arises from improper input validation within the weblog page template functionality, specifically when processing Velocity Text Language content. The vulnerability requires an attacker to possess administrative privileges for a specific weblog, making it a privilege escalation and code execution vector rather than a straightforward remote exploit. The affected component allows authenticated administrators to inject malicious VTL code that gets executed within the application's runtime environment, potentially enabling full system compromise.
The technical mechanism behind this vulnerability stems from the application's handling of Velocity Template Language expressions within weblog page templates. When administrators create or modify page templates, the system processes VTL code to generate dynamic content. However, insufficient sanitization allows crafted VTL expressions to bypass normal validation checks and execute arbitrary Java code on the server. This flaw directly maps to CWE-94, which describes "Improper Control of Generation of Code ('Code Injection')" and specifically relates to the improper handling of template processing that allows arbitrary code execution. The vulnerability exploits the Velocity engine's capability to execute Java code through its template processing mechanism, creating a path for attackers to leverage their administrative access into full system compromise.
From an operational impact perspective, this vulnerability poses significant risk to organizations relying on Apache Roller for their weblogging infrastructure. An attacker with administrative privileges can execute arbitrary commands with the privileges of the web application user, potentially leading to complete system compromise, data exfiltration, or lateral movement within the network. The attack requires only authenticated access to a weblog's administrative interface, making it particularly dangerous in environments where administrative credentials might be compromised or where multiple administrators have access to different weblogs. The vulnerability affects the confidentiality, integrity, and availability of the affected system, as attackers can modify content, delete data, or establish persistent access through the executed code.
Organizations should implement immediate mitigations including upgrading to Apache Roller version 5.1.2 or later, which contains the necessary patches to address this vulnerability. Additionally, administrators should enforce the principle of least privilege by limiting administrative access to only those users who require such privileges, reducing the attack surface for this specific vulnerability. Network segmentation and monitoring of administrative activities can help detect suspicious template modifications that might indicate exploitation attempts. The vulnerability also highlights the importance of input validation and output encoding in template processing systems, aligning with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: VBA Macros' and broader defensive strategies for preventing code injection attacks. Organizations should also consider implementing web application firewalls and application-level controls to monitor and filter template content submissions, particularly those containing Velocity-specific syntax that could lead to code execution.