CVE-2017-5231 in Metasploit Framework
Summary
by MITRE
All editions of Rapid7 Metasploit prior to version 4.13.0-2017020701 contain a directory traversal vulnerability in the Meterpreter stdapi CommandDispatcher.cmd_download() function. By using a specially-crafted build of Meterpreter, it is possible to write to an arbitrary directory on the Metasploit console with the permissions of the running Metasploit instance.
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Analysis
by VulDB Data Team • 06/21/2020
The vulnerability identified as CVE-2017-5231 represents a critical directory traversal flaw within the Rapid7 Metasploit framework affecting all editions prior to version 4.13.0-2017020701. This weakness specifically resides in the Meterpreter stdapi CommandDispatcher.cmd_download() function, which handles file download operations within the post-exploitation framework. The vulnerability stems from inadequate input validation and path manipulation handling within the download functionality, creating an opportunity for malicious actors to exploit the system's file handling mechanisms. The flaw operates at the application layer and can be classified under CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The technical exploitation of this vulnerability enables attackers to manipulate the file download process through a specially crafted Meterpreter build that can write files to arbitrary directories on the Metasploit console system. When an attacker successfully exploits this vulnerability, they can execute file operations with the same privileges as the running Metasploit instance, potentially leading to unauthorized file creation, modification, or deletion across the system. This privilege escalation occurs because the vulnerable function fails to properly sanitize or validate the file paths provided during download operations, allowing malicious input to bypass normal file system access controls. The attack vector leverages the inherent trust placed in legitimate Meterpreter operations, making it particularly dangerous as it can be executed through normal exploitation workflows without requiring additional authentication or privilege escalation mechanisms.
The operational impact of CVE-2017-5231 extends beyond simple file system manipulation to potentially compromise the entire security posture of systems running vulnerable Metasploit versions. An attacker who successfully exploits this vulnerability can establish persistent backdoors, modify critical system files, install malicious software, or exfiltrate sensitive data from the compromised system. The vulnerability affects not only the local system but also potentially exposes the broader network infrastructure, as Metasploit is commonly used for network reconnaissance and exploitation activities. This weakness creates a significant risk for security professionals who rely on Metasploit for legitimate penetration testing activities, as the same tools used for defensive purposes can be weaponized by adversaries to gain unauthorized access to system resources. The vulnerability aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1070.004 for indicator removal on host, as exploitation can involve creating malicious files and removing evidence of compromise.
Mitigation strategies for CVE-2017-5231 primarily focus on immediate version updates to Metasploit 4.13.0-2017020701 or later, which includes proper input validation and path sanitization within the affected CommandDispatcher.cmd_download() function. Organizations should implement comprehensive patch management procedures to ensure all Metasploit installations are updated promptly, as this vulnerability represents a known exploit that has been widely documented in security advisories and threat intelligence feeds. Additional protective measures include implementing network segmentation to limit access to systems running Metasploit, monitoring for unusual file system activity patterns, and conducting regular security assessments of penetration testing environments to identify potential exploitation vectors. Security teams should also consider implementing application whitelisting policies to restrict execution of unauthorized Meterpreter builds and establish strict access controls for Metasploit console environments to minimize the attack surface. The vulnerability demonstrates the importance of secure coding practices and proper input validation in security tools, particularly those with elevated privileges and access to system resources.