CVE-2024-47901: Siemens Intermesh 7177 RCE Vulnerability

CVE-2024-47901 Overview

A critical command injection vulnerability has been identified in Siemens InterMesh 7177 Hybrid 2.0 Subscriber and InterMesh 7707 Fire Subscriber devices. The web server of affected devices fails to properly sanitize input parameters in specific GET requests, allowing for arbitrary code execution at the operating system level. When combined with related vulnerabilities (CVE-2024-47902, CVE-2024-47903, CVE-2024-47904), this flaw could allow an unauthenticated remote attacker to execute arbitrary code with root privileges on the underlying system.

Critical Impact

Unauthenticated remote attackers can achieve root-level code execution on affected Siemens InterMesh devices through unsanitized GET request parameters, potentially compromising critical infrastructure communications systems.

Affected Products

• Siemens InterMesh 7177 Hybrid 2.0 Subscriber (All versions < V8.2.12)
• Siemens InterMesh 7707 Fire Subscriber Firmware (All versions < V7.2.12 only if IP interface is enabled)
• Siemens InterMesh 7707 Fire Subscriber Hardware

Discovery Timeline

• October 23, 2024 - CVE-2024-47901 published to NVD
• October 30, 2024 - Last updated in NVD database

Technical Details for CVE-2024-47901

Vulnerability Analysis

This vulnerability is classified as CWE-78 (OS Command Injection), affecting the web server component of Siemens InterMesh subscriber devices. The flaw exists in the request handling mechanism where user-supplied input parameters within specific GET requests are passed directly to system-level commands without adequate sanitization or validation.

The vulnerability is particularly dangerous because it can be exploited remotely over the network without requiring any authentication. When chained with the related vulnerabilities CVE-2024-47902, CVE-2024-47903, and CVE-2024-47904, attackers can escalate to full root privileges, giving them complete control over the affected device.

For the InterMesh 7707 Fire Subscriber, the vulnerability is only exploitable when the IP interface is enabled, which is not the default configuration. However, the InterMesh 7177 Hybrid 2.0 Subscriber is vulnerable in all versions prior to V8.2.12.

Root Cause

The root cause of this vulnerability lies in improper input validation within the web server's request handling logic. User-supplied parameters in certain GET requests are incorporated into operating system commands without proper sanitization, escaping, or validation. This allows specially crafted input containing shell metacharacters or command separators to break out of the intended command context and execute arbitrary commands.

Attack Vector

The attack vector is network-based, requiring no user interaction or authentication. An attacker with network access to the device's web interface can exploit this vulnerability by sending malicious GET requests with crafted parameters. The web server processes these parameters and passes them to the underlying operating system, where injected commands are executed.

The vulnerability manifests when the web server constructs system commands using unsanitized user input from GET request parameters. Attackers can inject shell metacharacters (such as ;, |, &&, or backticks) to append or chain malicious commands. When the web server executes the constructed command string, the injected commands run with the privileges of the web server process, which can lead to root-level access when combined with related privilege escalation vulnerabilities. For detailed technical information, refer to the Siemens Security Advisory SSA-333468.

Detection Methods for CVE-2024-47901

Indicators of Compromise

• Unusual or unexpected GET requests to the device web interface containing shell metacharacters (;, |, &&, `, $())
• Unexpected processes spawned by the web server process on affected devices
• Evidence of reverse shell connections or outbound network connections from the device to unknown IP addresses
• Unauthorized modifications to device configuration files or firmware

Detection Strategies

• Implement network intrusion detection rules to identify HTTP GET requests containing command injection patterns targeting InterMesh devices
• Monitor web server access logs for requests with suspicious parameter values containing shell metacharacters or encoded command sequences
• Deploy anomaly detection for process creation events on affected devices, particularly child processes spawned by the web server
• Utilize SentinelOne Singularity platform to detect and block exploitation attempts targeting embedded device web interfaces

Monitoring Recommendations

• Establish baseline network traffic patterns for InterMesh devices and alert on deviations
• Enable verbose logging on device web servers and forward logs to a centralized SIEM for analysis
• Monitor for unexpected firmware changes or configuration modifications on affected devices
• Implement network segmentation to limit exposure of vulnerable devices and enable east-west traffic monitoring

How to Mitigate CVE-2024-47901

Immediate Actions Required

• Update InterMesh 7177 Hybrid 2.0 Subscriber devices to version V8.2.12 or later immediately
• Update InterMesh 7707 Fire Subscriber devices to version V7.2.12 or later if IP interface is enabled
• If immediate patching is not possible, disable the IP interface on InterMesh 7707 Fire Subscriber devices (if not required)
• Isolate affected devices from untrusted networks and restrict access to the web interface to authorized IP addresses only

Patch Information

Siemens has released security updates to address this vulnerability. Detailed patch information and firmware downloads are available through the Siemens Security Advisory SSA-333468. Organizations should prioritize patching given the critical nature of this vulnerability and the potential for unauthenticated remote code execution with root privileges.

For InterMesh 7177 Hybrid 2.0 Subscriber, upgrade to firmware version V8.2.12 or later. For InterMesh 7707 Fire Subscriber, upgrade to firmware version V7.2.12 or later.

Workarounds

• Disable the IP interface on InterMesh 7707 Fire Subscriber devices if not operationally required (this is the default configuration)
• Implement network access controls to restrict web interface access to trusted management networks only
• Deploy a web application firewall (WAF) or reverse proxy in front of vulnerable devices to filter malicious requests
• Use VPN or other secure remote access solutions to protect device management interfaces from direct internet exposure

# Network segmentation example - restrict access to InterMesh device management interface
# Using iptables to limit web interface access to specific management network

# Allow access from trusted management network only
iptables -A INPUT -p tcp --dport 80 -s 10.10.10.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s 10.10.10.0/24 -j ACCEPT

# Drop all other web interface traffic
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP