CVE-2026-30799

Executive Summary

CVE-2026-30799 is a critical Missing Authentication for Critical Function vulnerability in RTI Connext Professional, specifically within its Security Plugins. This flaw allows an unauthenticated, remote attacker to perform Identity Spoofing, effectively bypassing the DDS (Data Distribution Service) security model. By exploiting this vulnerability, an attacker can impersonate any legitimate participant in a DDS system, leading to unauthorized data access, injection of malicious data, and disruption of critical real-time communications. The vulnerability affects a wide range of Connext Professional versions, from 5.3.0 up to, but not including, 7.7.0. Given the use of RTI Connext in mission-critical sectors like defense, aerospace, and industrial control systems, the potential for severe operational impact is high. No public proof-of-concept (PoC) or exploit code is currently available, but the technical details are sufficient for a determined adversary to develop one.

Supply Chain & Package Security

This vulnerability is not in a standard open-source package manager (NPM, PyPI, Go, Ruby) but in a commercial middleware product (RTI Connext Professional). The supply chain risk is significant for organizations that integrate this SDK into their own products. A compromised DDS participant can lead to cascading failures across an entire distributed system. Organizations must verify the provenance of their RTI Connext binaries and ensure they are sourced from the official vendor.

CVSS Breakdown & Threat Level

CVSS Score: 9.8 (Critical)

• Attack Vector (AV): Network (N) - The vulnerability is exploitable remotely over the network.
• Attack Complexity (AC): Low (L) - No special conditions or complex attack sequences are required.
• Privileges Required (PR): None (N) - The attacker does not need any prior authentication.
• User Interaction (UI): None (N) - No user action is required for exploitation.
• Scope (S): Unchanged (U) - The impact is confined to the vulnerable component.
• Confidentiality (C): High (H) - An attacker can read all data published by legitimate participants.
• Integrity (I): High (H) - An attacker can inject false data, corrupting the system's state.
• Availability (A): High (H) - An attacker can disrupt communication, causing denial of service.

Threat Level: Critical. The combination of network exploitability, no required privileges, and high impact on all three security pillars makes this a top-priority vulnerability for any organization using the affected software.

Deep Dive & Mechanics

The vulnerability resides in the Security Plugins of RTI Connext Professional. These plugins implement the DDS Security specification, which provides authentication, authorization, and encryption for DDS communications.

The core issue is a Missing Authentication for Critical Function (CWE-306). Specifically, the security plugin fails to properly validate the identity of a participant during the initial discovery and handshake process. In a properly secured DDS domain, participants must present valid credentials (e.g., certificates, shared secrets) to prove their identity. This vulnerability allows an attacker to craft a malicious DDS discovery packet that claims a false identity without providing the necessary proof.

The attack flow is as follows:

1. Discovery: The attacker's system sends a crafted RTPS (Real-Time Publish-Subscribe) discovery packet to the target DDS network.
2. Identity Spoofing: The packet contains a ParticipantBuiltinTopicData that claims the identity of a legitimate, authorized participant (e.g., a critical sensor or controller).
3. Bypass of Security Checks: The vulnerable Security Plugins do not enforce the authentication requirement for this specific discovery message. They accept the claimed identity as valid.
4. Establishment of Communication: The target system (e.g., a data subscriber) accepts the attacker as the legitimate participant and establishes a secure channel (if encryption is enabled, the attacker may not be able to decrypt existing traffic, but they can still inject new data).
5. Impact: The attacker can now:
   • Publish malicious data as the spoofed participant, corrupting the system's state.
   • Subscribe to data intended for the spoofed participant, leading to information disclosure.
   • Cause denial of service by sending malformed data or by impersonating a critical controller and issuing harmful commands.

Vulnerable vs. Patched Code

The exact code fix is proprietary to RTI, but the conceptual difference is clear.

Vulnerable Code (Conceptual):

// In the security plugin's participant discovery handler
void on_discovered_participant(ParticipantData* data) {
    // VULNERABLE: No authentication check before accepting the identity
    if (is_participant_allowed(data->domain_id)) {
        // Accept the participant's claimed identity without verification
        add_participant_to_domain(data->participant_guid, data->claimed_identity);
    }
}

Patched Code (Conceptual):

// In the security plugin's participant discovery handler
void on_discovered_participant(ParticipantData* data) {
    // PATCHED: Enforce authentication before accepting the identity
    if (is_participant_allowed(data->domain_id) && 
        authenticate_participant(data->participant_guid, data->auth_token)) {
        // Only accept the identity after successful authentication
        add_participant_to_domain(data->participant_guid, data->verified_identity);
    } else {
        // Reject the unauthenticated participant
        log_security_event("Authentication failure for participant", data->participant_guid);
    }
}

The patch ensures that the authenticate_participant() function is called and must succeed before the participant's identity is trusted. This prevents an attacker from simply claiming a valid identity without the corresponding credentials.

Exploitation & Lab Setup

Red Team (Offensive)

Objective: Spoof a legitimate DDS participant to inject malicious data.

Lab Setup:

1. Environment: Two machines on the same network. One running a legitimate RTI Context application (e.g., a sensor publishing temperature data). The other is the attacker's machine.
2. Tools: Wireshark (for traffic analysis), a custom Python script using the struct and socket libraries to craft raw RTPS packets, or a modified DDS library.
3. Steps:
   • Reconnaissance: Use Wireshark to capture DDS discovery traffic. Identify the participant_guid and claimed_identity of a legitimate participant.
   • Craft Malicious Packet: Create a raw UDP packet to the DDS discovery multicast address (e.g., 239.255.0.1:7400). The packet should contain a valid RTPS header and a ParticipantBuiltinTopicData submessage, but with the attacker's network address and the stolen participant_guid.
   • Send Packet: Send the crafted packet. The vulnerable system will accept the attacker as the legitimate participant.
   • Publish Malicious Data: The attacker can now publish data under the spoofed identity. For example, if the legitimate participant was a temperature sensor, the attacker can publish a false temperature reading.

Example Python Snippet (Conceptual):

import socket
import struct

# Craft a minimal RTPS discovery packet (simplified)
def craft_spoofed_discovery_packet(spoofed_guid, attacker_ip):
    # RTPS Header
    header = b'\x52\x54\x50\x53'  # "RTPS" magic
    header += struct.pack('!H', 2)  # Version
    header += struct.pack('!I', 0)  # Vendor ID
    header += struct.pack('!I', 0)  # Timestamp
    # ... (more complex structure for ParticipantBuiltinTopicData)
    # This is a simplified placeholder
    payload = b'\x00' * 100  # Placeholder for the actual data
    return header + payload

sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 2)
packet = craft_spoofed_discovery_packet(b'\x01\x02\x03\x04', '192.168.1.100')
sock.sendto(packet, ('239.255.0.1', 7400))

Blue Team (Defensive)

Objective: Detect and block identity spoofing attempts.

Detection Steps:

1. Network Monitoring: Monitor for multiple DDS discovery packets claiming the same participant_guid from different source IP addresses. This is a strong indicator of a spoofing attack.
2. Anomaly Detection: Establish a baseline of legitimate DDS participants. Alert on any new participant that appears without a corresponding authentication handshake.
3. Log Analysis: Enable detailed logging on RTI Connext Security Plugins. Look for log entries indicating "Authentication failure" or "Invalid identity claim."
4. Honeypot Participants: Deploy fake DDS participants that are not used in production. Any attempt to communicate with them is a sign of reconnaissance.

Mitigation Steps:

1. Patch Immediately: Apply the vendor patch or upgrade to Connext Professional 7.7.0.
2. Network Segmentation: Isolate DDS traffic to trusted network segments. Use firewalls to block DDS discovery traffic (UDP 7400) from untrusted networks.
3. Enable Strong Authentication: Ensure that DDS Security is configured to require authentication for all participants. Use X.509 certificates or pre-shared keys.
4. Intrusion Prevention System (IPS): Deploy custom Suricata rules (see Detection Engineering) to detect and block malicious DDS discovery packets.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Multiple DDS discovery packets (UDP port 7400) with the same participant_guid but different source IP addresses.
  • DDS discovery packets from unexpected or external IP ranges.
  • Anomalous DDS traffic patterns, such as a sudden increase in discovery packets.
• Host IOCs:
  • RTI Connext logs containing "Authentication failure" or "Invalid identity" errors.
  • Unexpected DDS participants appearing in the domain.
  • Unusual network connections from the RTI process to unknown IPs.
• File IOCs:
  • Modified RTI configuration files (e.g., USER_QOS_PROFILES.xml) that disable security features.

Detection Engineering

YARA Rule

rule CVE_2026_30799_RTI_Identity_Spoofing {
    meta:
        description = "Detects potential exploitation of CVE-2026-30799 by identifying crafted RTPS discovery packets"
        author = "Valters IT"
        date = "2025-04-10"
        hash = "unknown"
    strings:
        $rtps_magic = { 52 54 50 53 } // "RTPS"
        $participant_data = { 00 01 } // Submessage ID for ParticipantBuiltinTopicData
        $spoofed_guid = { 01 02 03 04 } // Example: Replace with known legitimate GUIDs
    condition:
        $rtps_magic at 0 and $participant_data and #spoofed_guid > 1
}

Sigma Rule

title: CVE-2026-30799 - RTI Connext Identity Spoofing
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects multiple DDS discovery packets with the same participant GUID from different source IPs.
author: Valters IT
date: 2025-04-10
logsource:
    category: network_connection
    product: zeek
detection:
    selection:
        proto: "udp"
        destination_port: 7400
    condition: selection
    timeframe: 5m
    aggregation:
        - field: destination_ip
          method: count
          condition: gt 5
        - field: source_ip
          method: distinct_count
          condition: gt 1
    condition: selection and aggregation
falsepositives:
    - Legitimate network reconfiguration
level: high

Suricata Rule

alert udp any any -> any 7400 (msg:"CVE-2026-30799 - RTI Connext Identity Spoofing Attempt"; content:"|52 54 50 53|"; depth:4; content:"|00 01|"; within:20; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Action:

   • Patch: Upgrade to RTI Connext Professional version 7.7.0 or apply the specific patch for your version branch (5.3., 6.0., 6.1., 7.3.). Contact RTI support for patch details.
   • Workaround: If patching is not immediately possible, disable the DDS Security Plugins and rely on network-level security (e.g., IPsec, VPNs) to isolate DDS traffic. This is a temporary measure and reduces security.

2. Long-Term Mitigation:

   • Network Segmentation: Place all DDS participants on a dedicated, isolated VLAN. Use firewalls to block DDS discovery traffic (UDP 7400) from all other networks.
   • Authentication Hardening: Ensure that DDS Security is configured with the strongest available authentication mechanisms (e.g., X.509 certificates with mutual TLS).
   • Continuous Monitoring: Implement the detection rules provided in this report to monitor for exploitation attempts.
   • Vendor Communication: Subscribe to RTI security advisories to receive timely updates on future vulnerabilities.

Valters IT
DevSecOps & Cyber Threat Intelligence