CVE-2018-3757 in pdf-image
Summary
by MITRE
Command injection exists in pdf-image v2.0.0 due to an unescaped string parameter.
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Analysis
by VulDB Data Team • 03/19/2023
The vulnerability identified as CVE-2018-3757 represents a critical command injection flaw within the pdf-image node.js module version 2.0.0. This security weakness stems from improper input validation and sanitization mechanisms that fail to adequately escape string parameters before incorporating them into system commands. The module, designed to process pdf files and convert them to image formats, inadvertently exposes a pathway for malicious actors to execute arbitrary commands on the underlying system through crafted input parameters. The vulnerability manifests when user-supplied data is directly concatenated into shell commands without proper sanitization, creating an environment where attackers can manipulate the execution flow of the application.
The technical exploitation of this command injection vulnerability follows a pattern consistent with CWE-77 and CWE-88 categories, where insufficient input sanitization allows attackers to inject malicious commands that get executed within the system context. The flaw specifically affects the pdf-image module's handling of image processing parameters, where unescaped user input can be interpreted by the shell as additional commands rather than mere data. This type of vulnerability falls under the ATT&CK technique T1059.001 for command and scripting interpreter, specifically targeting the execution of system commands through shell injection. The attack vector typically involves crafting malicious input that gets processed by the pdf-image module and subsequently passed to underlying system commands without proper parameter escaping, enabling arbitrary code execution with the privileges of the affected application.
The operational impact of CVE-2018-3757 extends beyond simple privilege escalation, as successful exploitation can lead to complete system compromise, data exfiltration, and persistence mechanisms being established. An attacker who successfully exploits this vulnerability gains the ability to execute commands on the target system with the same privileges as the pdf-image module process, which typically runs with elevated permissions to perform image processing tasks. This creates a significant risk for environments where the module is used in web applications or automated processing pipelines, as it provides a direct pathway for attackers to move laterally within the network infrastructure. The vulnerability affects any system that utilizes the pdf-image module version 2.0.0 for processing user-supplied pdf files, making it particularly dangerous in multi-tenant environments or applications that accept untrusted input for pdf conversion tasks.
Mitigation strategies for CVE-2018-3757 should focus on immediate remediation through version updates, as the vulnerability has been addressed in subsequent releases of the pdf-image module. Organizations should implement comprehensive input validation and sanitization measures, ensuring that all user-supplied parameters are properly escaped before being passed to system commands. The implementation of proper parameterization techniques and the adoption of secure coding practices that avoid direct shell command construction from user input forms the foundation of effective protection. Additionally, system administrators should consider implementing network segmentation and privilege separation to limit the potential impact of successful exploitation attempts. The use of application whitelisting and mandatory access controls can further reduce the risk surface, while regular security audits and dependency monitoring help identify and remediate similar vulnerabilities across the software ecosystem. Organizations should also implement proper logging and monitoring mechanisms to detect suspicious command execution patterns that may indicate exploitation attempts.