CVE-2019-5413 in morgan Package
Summary
by MITRE
An attacker can use the format parameter to inject arbitrary commands in the npm package morgan < 1.9.1.
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Analysis
by VulDB Data Team • 05/18/2020
The vulnerability identified as CVE-2019-5413 represents a critical command injection flaw within the morgan npm package, which has been widely adopted for HTTP request logging in node.js applications. This vulnerability specifically affects versions prior to 1.9.1 and stems from improper input validation within the format parameter handling mechanism. The morgan package serves as a logging middleware for express.js applications, making it a common target for attackers seeking to exploit server-side vulnerabilities. When developers configure morgan with user-provided format strings, the package fails to adequately sanitize these inputs, creating an avenue for malicious command execution.
The technical flaw manifests through the insecure processing of format parameters that can contain shell command injection payloads. Attackers can manipulate the format string parameter to include malicious commands that get executed within the context of the node.js process. This occurs because the vulnerable implementation does not properly escape or validate format specifiers that may contain shell metacharacters. The vulnerability falls under CWE-77 which categorizes improper neutralization of special elements used in commands, and specifically relates to CWE-94 which covers inadequate control of generation of code. The flaw allows for arbitrary code execution with the privileges of the node.js process, potentially enabling full system compromise if the application runs with elevated permissions.
The operational impact of this vulnerability extends beyond simple command injection, as it can enable attackers to perform a wide range of malicious activities including data exfiltration, privilege escalation, and persistence mechanisms. Since morgan is frequently used in production web applications, the attack surface is extensive and affects numerous organizations. The vulnerability can be exploited through various vectors including web application interfaces, API endpoints, or any input that gets processed through the logging middleware. This allows attackers to execute commands such as system information gathering, file manipulation, network reconnaissance, and potentially establish reverse shells. The attack can be particularly devastating in containerized environments or cloud deployments where node.js applications may have broader system access than intended.
Mitigation strategies for CVE-2019-5413 require immediate version upgrades to morgan 1.9.1 or later, which includes proper input sanitization and validation. Organizations should conduct comprehensive inventory assessments to identify all systems utilizing vulnerable versions of the package and implement automated patch management processes. Additional defensive measures include implementing input validation at application boundaries, employing web application firewalls to detect suspicious format parameter patterns, and monitoring for unusual logging activities that may indicate exploitation attempts. Security teams should also consider implementing principle of least privilege for node.js processes and utilizing container security controls to limit potential damage from successful exploitation attempts. The vulnerability demonstrates the critical importance of dependency security management and highlights how seemingly benign logging components can become attack vectors in modern application architectures.