CVE-2020-7980: Intellian Aptus Web RCE Vulnerability

CVE-2020-7980 Overview

CVE-2020-7980 is a critical command injection vulnerability affecting Intellian Aptus Web version 1.24. This vulnerability allows remote attackers to execute arbitrary operating system commands by manipulating the Q field within JSON data sent to the cgi-bin/libagent.cgi URI. Successful exploitation may require a valid session cookie (sid) for authentication to the default Intellian account, though this presents minimal barrier given the use of default credentials.

Critical Impact

Remote attackers can achieve complete system compromise by executing arbitrary OS commands on vulnerable Intellian satellite communication systems, potentially affecting maritime, aviation, and military communication infrastructure.

Affected Products

• Intelliantech Aptus Web 1.24
• Intellian satellite terminal systems running vulnerable firmware
• Systems utilizing cgi-bin/libagent.cgi endpoint

Discovery Timeline

• 2020-01-25 - CVE-2020-7980 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2020-7980

Vulnerability Analysis

This command injection vulnerability (CWE-78) resides in the libagent.cgi CGI script, which fails to properly sanitize user-supplied input within the Q field of JSON request data. When processing requests to cgi-bin/libagent.cgi, the application directly incorporates user input into system command execution without adequate validation or escaping.

The vulnerability is particularly severe in satellite communication environments where Intellian systems are deployed. These devices often serve critical communication infrastructure in maritime, aviation, and government/military applications. Compromise of such systems could result in communication disruption, unauthorized access to sensitive communications, or establishment of persistent backdoor access.

Root Cause

The root cause is improper input validation (CWE-78: Improper Neutralization of Special Elements used in an OS Command) in the libagent.cgi CGI handler. The application accepts JSON-formatted data containing a Q field parameter and passes this data to underlying system commands without proper sanitization, allowing shell metacharacters and command separators to be interpreted by the operating system shell.

Attack Vector

The attack is network-based, requiring only HTTP access to the vulnerable CGI endpoint. An attacker crafts a malicious JSON payload containing OS command sequences within the Q field and submits it to the cgi-bin/libagent.cgi endpoint. While authentication via a valid sid cookie may be required, Intellian devices often ship with default credentials, significantly lowering the exploitation barrier.

The attacker sends a specially crafted HTTP POST request to the /cgi-bin/libagent.cgi URI with JSON data containing command injection payloads in the Q parameter. Shell metacharacters such as semicolons, pipes, or backticks can be used to append or chain arbitrary commands. For detailed technical exploitation information, refer to the GitHub PoC for CVE-2020-7980 and Packet Storm RCE Advisory.

Detection Methods for CVE-2020-7980

Indicators of Compromise

• Unusual HTTP POST requests to /cgi-bin/libagent.cgi containing shell metacharacters (;, |, `, $()) in JSON payloads
• Unexpected outbound connections or reverse shells originating from Intellian devices
• Modified system files or unauthorized user accounts on Intellian terminal systems
• Suspicious processes spawned by CGI handlers or web server processes

Detection Strategies

• Monitor web server logs for requests to cgi-bin/libagent.cgi with abnormal JSON payload content
• Implement intrusion detection rules to flag command injection patterns in HTTP traffic targeting Intellian devices
• Deploy network segmentation to isolate satellite communication systems and alert on unexpected traffic patterns
• Audit authentication logs for use of default Intellian credentials

Monitoring Recommendations

• Establish baseline network behavior for Intellian devices and alert on deviations
• Configure SIEM correlation rules to detect command injection attack patterns against CGI endpoints
• Monitor for DNS queries or network connections to known malicious infrastructure from satellite terminal systems

How to Mitigate CVE-2020-7980

Immediate Actions Required

• Change default credentials on all Intellian Aptus Web interfaces immediately
• Restrict network access to the Aptus Web management interface using firewall rules and network segmentation
• Monitor for exploitation attempts using web application firewall (WAF) rules targeting command injection patterns
• Contact Intelliantech for firmware updates or patches addressing this vulnerability

Patch Information

No vendor advisory URLs were identified in the available data. Organizations should contact Intelliantech directly for updated firmware that addresses this command injection vulnerability. In the interim, compensating controls should be applied.

For additional technical details on this vulnerability, see the Blog Post on Intellian RCE.

Workarounds

• Implement strict network access controls to limit management interface exposure to trusted IP addresses only
• Deploy a web application firewall (WAF) with rules to detect and block command injection payloads in JSON data
• Disable the Aptus Web interface if remote management is not operationally required
• Implement network monitoring to detect and respond to exploitation attempts in real-time

# Example: Restrict access to Intellian management interface using iptables
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP