CVE-2026-28773: IDC SuperFlex Satellite Receiver RCE Flaw

CVE-2026-28773 Overview

CVE-2026-28773 is a critical OS Command Injection vulnerability affecting the web-based Ping diagnostic utility (/IDC_Ping/main.cgi) in the International Datacasting Corporation (IDC) SFX Series SuperFlex Satellite Receiver Web Management Interface version 101. The vulnerability stems from insecure parsing of the IPaddr parameter, allowing authenticated attackers to bypass server-side semicolon exclusion checks by using alternate shell metacharacters (such as the pipe | operator) to append and execute arbitrary shell commands with root privileges.

Critical Impact

Authenticated attackers can achieve remote code execution with root privileges on affected satellite receiver devices, potentially compromising broadcast infrastructure and satellite communication systems.

Affected Products

• International Datacasting Corporation (IDC) SFX Series SuperFlex Satellite Receiver
• IDC SFX Web Management Interface version 101
• /IDC_Ping/main.cgi diagnostic utility

Discovery Timeline

• 2026-03-04 - CVE-2026-28773 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2026-28773

Vulnerability Analysis

This vulnerability is classified under CWE-78 (Improper Neutralization of Special Elements used in an OS Command), commonly known as OS Command Injection. The web-based Ping diagnostic utility in the IDC SFX Series satellite receivers fails to properly sanitize user-supplied input before incorporating it into system commands.

The application implements a server-side filter that attempts to block semicolon (;) characters to prevent command chaining. However, this security control is insufficient as attackers can bypass it by using alternative shell metacharacters. The pipe operator (|) allows command chaining in Unix-like systems and is not filtered by the application's input validation logic.

When an authenticated user submits a crafted payload through the IPaddr parameter, the application passes the unsanitized input directly to a shell command, resulting in arbitrary command execution. Since the web management interface typically runs with elevated privileges, the injected commands execute with root access, giving attackers complete control over the device.

Root Cause

The root cause of this vulnerability is inadequate input validation and sanitization in the Ping diagnostic utility. The application relies on a blocklist approach that only filters semicolons, failing to account for other shell metacharacters that can be used for command injection. This includes the pipe operator (|), backticks (`), command substitution ($()), and logical operators (&&, ||).

Additionally, the application directly concatenates user input into shell commands without proper escaping or parameterization, violating secure coding principles for handling external input in command execution contexts.

Attack Vector

The attack requires network access to the web management interface and valid authentication credentials. Once authenticated, an attacker can navigate to the Ping diagnostic utility and submit a malicious payload in the IPaddr parameter field.

The vulnerability is exploited by injecting shell metacharacters that the application fails to filter. For example, instead of using a semicolon (which is blocked), an attacker can use the pipe operator to chain arbitrary commands after the intended ping command. The injected commands execute with root privileges, allowing the attacker to:

• Establish reverse shells for persistent access
• Modify device configuration and firmware
• Intercept or manipulate satellite communications
• Pivot to other systems on the network
• Install backdoors or malicious payloads

For detailed technical information about this vulnerability, refer to the security researcher's disclosure.

Detection Methods for CVE-2026-28773

Indicators of Compromise

• Unusual HTTP POST requests to /IDC_Ping/main.cgi containing pipe operators (|) or other shell metacharacters in the IPaddr parameter
• Unexpected outbound network connections from satellite receiver devices
• Anomalous process execution originating from the web server process
• Unauthorized configuration changes on IDC SFX Series devices
• Evidence of shell spawning or command execution in web server logs

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block requests containing shell metacharacters in the IPaddr parameter
• Monitor HTTP traffic to /IDC_Ping/main.cgi for payloads containing |, backticks, $(), &&, or || patterns
• Deploy intrusion detection system (IDS) signatures for command injection patterns targeting the Ping utility
• Configure SIEM correlation rules to alert on multiple failed authentication attempts followed by suspicious diagnostic utility access

Monitoring Recommendations

• Enable detailed logging on all IDC SFX Series satellite receivers, including web server access logs and authentication events
• Implement network traffic analysis to detect anomalous communication patterns from satellite infrastructure
• Establish baseline behavior for legitimate Ping utility usage to identify deviations indicating exploitation
• Monitor for unexpected processes or network connections spawned by the web management interface

How to Mitigate CVE-2026-28773

Immediate Actions Required

• Restrict network access to the web management interface using firewall rules and network segmentation
• Implement strong authentication controls and review all accounts with access to the management interface
• Place IDC SFX Series devices behind a VPN or jump server to limit exposure
• Disable the Ping diagnostic utility if not operationally required
• Audit access logs for any suspicious activity indicating prior exploitation attempts

Patch Information

At the time of publication, no vendor patch information is available for this vulnerability. Organizations should monitor International Datacasting Corporation communications for security updates. Refer to the vulnerability disclosure for the latest information on remediation guidance.

Workarounds

• Implement network-level access controls (ACLs) to restrict management interface access to trusted IP addresses only
• Deploy a web application firewall (WAF) with rules to block shell metacharacters in diagnostic utility parameters
• Use network segmentation to isolate satellite receiver infrastructure from general network access
• Consider implementing a reverse proxy with input validation to filter malicious requests before they reach the device

# Example firewall rule to restrict management interface access
# Restrict access to management interface to specific trusted IPs
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP

# Alternative: Block access to vulnerable CGI endpoint
iptables -A INPUT -p tcp --dport 80 -m string --string "/IDC_Ping/main.cgi" --algo bm -j DROP