CVE-2025-55055: Maxum Rumpus RCE Vulnerability

CVE-2025-55055 Overview

CVE-2025-55055 is a critical OS Command Injection vulnerability (CWE-78) affecting Maxum Rumpus, a file transfer server software. This vulnerability allows attackers to inject and execute arbitrary operating system commands through improper neutralization of special elements in user-controlled input. The flaw enables remote attackers to compromise the underlying server without requiring authentication, potentially leading to complete system takeover.

Critical Impact

Remote unauthenticated attackers can execute arbitrary OS commands on systems running vulnerable versions of Maxum Rumpus, leading to complete system compromise, data exfiltration, and lateral movement within the network.

Affected Products

• Maxum Rumpus version 9.0.12
• Maxum Rumpus (additional versions may be affected)

Discovery Timeline

• 2025-11-17 - CVE-2025-55055 published to NVD
• 2025-11-24 - Last updated in NVD database

Technical Details for CVE-2025-55055

Vulnerability Analysis

This vulnerability stems from improper input validation in Maxum Rumpus file transfer server software. The application fails to properly sanitize user-supplied input before incorporating it into operating system commands, allowing attackers to inject malicious command sequences. When exploited, the injected commands execute with the same privileges as the Rumpus application process, which often runs with elevated permissions to manage file transfers.

The network-accessible nature of this vulnerability combined with the lack of authentication requirements makes it particularly dangerous for internet-facing deployments. Successful exploitation grants attackers the ability to read sensitive files, modify system configurations, install backdoors, or pivot to other systems on the network.

Root Cause

The root cause of CVE-2025-55055 is the failure to properly neutralize special characters and command sequences (such as semicolons, pipes, backticks, and shell metacharacters) in user input before passing it to system command execution functions. This allows attackers to break out of the intended command context and execute arbitrary commands. The application lacks proper input validation, output encoding, and parameterized command execution patterns that would prevent command injection attacks.

Attack Vector

This vulnerability is exploitable over the network without requiring authentication or user interaction. An attacker can craft malicious requests containing OS command injection payloads targeting vulnerable input fields or parameters in the Rumpus application. The injected commands are then executed by the underlying operating system shell.

Typical command injection payloads might include shell metacharacters such as:

• Command separators (;, &&, ||)
• Command substitution sequences (`command`, $(command))
• Pipe operators (|)

These payloads allow attackers to chain arbitrary commands onto legitimate application operations. For detailed technical information, refer to the Israeli Government CVE Advisories.

Detection Methods for CVE-2025-55055

Indicators of Compromise

• Unusual process spawning from the Rumpus application process, particularly shell processes (cmd.exe, bash, sh, powershell)
• Unexpected outbound network connections originating from the Rumpus server
• Suspicious log entries containing shell metacharacters or encoded command sequences
• File system modifications in unexpected directories or creation of new files by the Rumpus process
• Anomalous system resource utilization patterns indicative of cryptomining or data exfiltration

Detection Strategies

• Deploy web application firewall (WAF) rules to detect and block common OS command injection patterns in HTTP requests
• Monitor application and system logs for command injection indicators such as shell metacharacters in request parameters
• Implement network traffic analysis to identify unusual connections or data transfers from the Rumpus server
• Configure endpoint detection and response (EDR) solutions to alert on suspicious child process creation from the Rumpus application

Monitoring Recommendations

• Enable verbose logging on the Rumpus application to capture detailed request information
• Set up real-time alerting for suspicious activity patterns identified by SIEM solutions
• Monitor network egress traffic for command-and-control (C2) communication patterns
• Implement file integrity monitoring on critical system directories
• Review authentication logs for anomalous access patterns to the file transfer server

How to Mitigate CVE-2025-55055

Immediate Actions Required

• Identify all instances of Maxum Rumpus 9.0.12 in your environment and assess their exposure
• Restrict network access to Rumpus servers using firewall rules to limit exposure to trusted networks only
• Implement web application firewall (WAF) rules to filter common command injection payloads
• Monitor affected systems for signs of compromise while awaiting vendor patches
• Consider temporarily disabling or isolating vulnerable Rumpus instances if they are not business-critical

Patch Information

At the time of publication, no official patch information has been released. Organizations should monitor the Israeli Government CVE Advisories and the Maxum vendor website for security updates. Apply vendor-released patches immediately when available.

Workarounds

• Implement network segmentation to isolate Rumpus servers from critical infrastructure
• Deploy input validation at the network perimeter using WAF or reverse proxy with strict filtering rules
• Restrict access to the Rumpus application to only authorized IP addresses or VPN connections
• Run the Rumpus application with least-privilege permissions to limit the impact of successful exploitation
• Disable any unnecessary features or modules in Rumpus that may expand the attack surface

# Example firewall rule to restrict Rumpus access (adjust ports as needed)
# Only allow connections from trusted management network
iptables -A INPUT -p tcp --dport 80 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP