CVE-2026-28777: IDC SFX2100 Auth Bypass Vulnerability

CVE-2026-28777 Overview

A hardcoded credentials vulnerability exists in the International Datacasting Corporation (IDC) SFX2100 Satellite Receiver. The device ships with a trivial password for the user (usr) account, allowing remote unauthenticated attackers to gain unauthorized SSH access to the system. While users are initially dropped into a restricted shell environment, attackers can trivially spawn a complete PTY to obtain a fully interactive shell, significantly expanding their access and control over the compromised device.

Critical Impact

Remote attackers can exploit hardcoded credentials to gain SSH access to satellite receiver infrastructure, potentially compromising broadcast systems and sensitive communications.

Affected Products

• International Datacasting Corporation (IDC) SFX2100 Satellite Receiver

Discovery Timeline

• 2026-03-04 - CVE-2026-28777 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2026-28777

Vulnerability Analysis

This vulnerability is classified as CWE-798 (Use of Hard-coded Credentials), a critical security flaw where authentication credentials are embedded directly into the device firmware or configuration. In the case of the IDC SFX2100 Satellite Receiver, the user account is configured with a trivial, easily guessable password that remains constant across all deployed devices.

The flaw enables unauthorized network-based access without requiring any prior authentication or special privileges. An attacker can remotely connect to the device via SSH using the known default credentials. Once authenticated, although the system initially places the attacker in a restricted shell environment designed to limit available commands and functionality, this protection mechanism can be easily bypassed to spawn a complete pseudo-terminal (PTY), granting full interactive shell access.

Root Cause

The root cause of this vulnerability is the use of hardcoded credentials in the device firmware. Rather than requiring unique, strong credentials to be configured during deployment or generating random credentials per device, the manufacturer shipped the SFX2100 with a static, trivial password for the user account. This practice violates fundamental security principles and exposes all deployed devices to the same attack vector once the credential becomes known.

Attack Vector

The attack vector is network-based, requiring only network accessibility to the target device's SSH service (typically port 22). The attack flow proceeds as follows:

1. Attacker identifies an exposed SFX2100 Satellite Receiver on the network
2. Attacker initiates an SSH connection to the device using the known trivial credentials for the user account
3. Upon successful authentication, the attacker lands in a restricted shell
4. The attacker executes shell escape techniques to spawn a complete PTY, bypassing the restricted shell limitations
5. With full interactive shell access, the attacker can explore the system, access sensitive data, modify configurations, or establish persistence

The exploitation requires no user interaction and presents minimal complexity, making it highly accessible to attackers of varying skill levels.

Detection Methods for CVE-2026-28777

Indicators of Compromise

• Unexpected SSH login attempts or successful authentications to SFX2100 devices from unfamiliar IP addresses
• Multiple failed login attempts followed by successful authentication using the user account
• Unusual process spawning or PTY allocation events on satellite receiver systems
• Configuration changes or new user accounts created on affected devices

Detection Strategies

• Monitor SSH authentication logs for login attempts using the user account on SFX2100 devices
• Implement network intrusion detection rules to identify SSH brute-force patterns targeting satellite receiver infrastructure
• Deploy endpoint detection capabilities to identify restricted shell escape attempts and PTY spawning
• Establish baseline network behavior for satellite receivers and alert on deviations

Monitoring Recommendations

• Enable comprehensive SSH logging on all SFX2100 devices if supported
• Implement centralized log collection for all satellite receiver infrastructure
• Configure real-time alerting for successful SSH logins from non-administrative sources
• Conduct periodic credential audits to identify devices still using default credentials

How to Mitigate CVE-2026-28777

Immediate Actions Required

• Change the default password for the user account immediately on all deployed SFX2100 devices
• Disable SSH access if not required for operational purposes
• Implement network segmentation to isolate satellite receiver infrastructure from untrusted networks
• Deploy firewall rules restricting SSH access to authorized management IP addresses only

Patch Information

Consult the Abdul MHS Blog Vulnerability Analysis for detailed technical information about this vulnerability. Contact International Datacasting Corporation directly for firmware updates or official guidance on remediation. Organizations should verify whether updated firmware is available that addresses the hardcoded credentials issue.

Workarounds

• Implement network-level access controls to restrict SSH connectivity to trusted management networks only
• Configure a VPN or jump host requirement for all remote administrative access to satellite receivers
• Deploy an intrusion prevention system (IPS) to monitor and block suspicious SSH connection attempts
• Consider disabling the affected user account entirely if system functionality permits

# Example network restriction configuration (firewall/iptables)
# Restrict SSH access to SFX2100 devices to management VLAN only
iptables -A INPUT -p tcp --dport 22 -s 10.0.100.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 22 -j DROP