CVE-2026-9154 in InsightConnect Sed Plugin
Summary
by MITRE • 06/25/2026
Arbitrary File Write vulnerability in Rapid7 InsightConnect Sed Plugin on Linux allows authenticated attackers to write attacker-controlled content to arbitrary file paths via the expression parameter.
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Analysis
by VulDB Data Team • 06/25/2026
This vulnerability represents a critical arbitrary file write flaw in the Rapid7 InsightConnect Sed plugin running on linux systems, where authenticated attackers can manipulate the expression parameter to write malicious content to any file path within the system's filesystem. The issue stems from insufficient input validation and sanitization mechanisms that fail to properly restrict file path traversal or validate the intended destination of written files. Attackers with valid credentials can exploit this weakness to overwrite critical system files, inject malicious code into configuration files, or create backdoor persistence mechanisms by targeting writable directories accessible through the plugin's execution context. The vulnerability directly maps to CWE-22 Improper Limitation of a Pathname to a Restricted Directory and CWE-73 Hardcoded File Name. From an operational security perspective, this flaw significantly elevates the risk for organizations using InsightConnect platforms, as it allows lateral movement and persistent access once initial authentication is achieved. The ATT&CK framework categorizes this vulnerability under T1059 Command and Scripting Interpreter and T1486 Data Encrypted for Impact, as attackers can leverage the arbitrary write capability to deploy malicious payloads or encrypt critical files. The technical exploitation requires an authenticated session with sufficient privileges to interact with the Sed plugin functionality, making it particularly dangerous in environments where administrative accounts might be compromised or where privilege escalation occurs through other attack vectors.
The vulnerability's impact extends beyond simple file overwrites as attackers can target system configuration files, binary executables, or log files to establish persistent access or disrupt normal operations. When exploited effectively, this weakness enables attackers to modify the behavior of legitimate system processes or create new malicious processes that execute under elevated privileges. The lack of proper path validation means that even seemingly benign input parameters can be manipulated to traverse directories and write content to critical system locations. Security controls such as file permission checks, directory restrictions, and input sanitization mechanisms appear to be bypassed in the plugin's implementation, creating an attack surface that allows for direct manipulation of the filesystem. Organizations using InsightConnect platforms are particularly at risk since these plugins often run with elevated privileges to perform their intended functions, making any arbitrary write vulnerability potentially devastating.
Mitigation strategies should focus on implementing strict input validation and sanitization measures that prevent path traversal attempts and validate all file paths against a predefined whitelist of acceptable destinations. The plugin configuration must enforce proper access controls and privilege separation to minimize the impact of potential exploitation. Organizations should immediately apply vendor patches or updates when available, while implementing network segmentation to limit access to the InsightConnect platform to only authorized administrative users. Additional defensive measures include monitoring for unusual file modification patterns, implementing file integrity monitoring solutions, and conducting regular security assessments of plugin configurations. The principle of least privilege must be enforced across all system components, ensuring that plugins operate with minimal required permissions rather than elevated privileges. Security teams should also consider implementing automated vulnerability scanning tools that can detect similar issues in other third-party components and plugins within their environment to prevent future exploitation attempts.