CVE-2024-34047

Executive Summary

CVE-2024-34047 is a critical memory safety vulnerability in the O-RAN RIC (Radio Intelligent Controller) I-Release e2mgr component. The flaw resides in the RicServiceUpdateHandler function, which lacks proper array size checks before processing service update requests. This omission can lead to an out-of-bounds write (CWE-787), potentially allowing an unauthenticated attacker to corrupt memory, crash the service, or achieve remote code execution. The O-RAN ecosystem is foundational to open 5G networks, making this vulnerability a high-priority threat for telecom operators and vendors deploying O-RAN compliant infrastructure.

The vulnerability has a CVSS score of 0.0 in the NVD record, but this is likely a placeholder or error. Based on the nature of the flaw (lack of array bounds checking in a network-facing component), the actual severity is expected to be high (CVSS 7.5–9.8). No public proof-of-concept (PoC) or exploit code has been released as of this report. The EPSS score is 0.0%, indicating low exploitation activity in the wild, but this may change as more details emerge.

Supply Chain & Package Security

This vulnerability affects the O-RAN RIC I-Release, which is distributed as source code and container images. The e2mgr component is a critical part of the RIC platform, handling E2 interface connections between the RIC and O-RAN nodes. Organizations using O-RAN software must verify their supply chain for affected versions and apply patches or mitigations as soon as they become available.

CVSS Breakdown & Threat Level

While the official CVSS vector is unknown, a reasonable assessment based on the vulnerability description is:

• Attack Vector (AV): Network (N) – The e2mgr service listens on network ports.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): None (N) – No authentication needed.
• User Interaction (UI): None (N) – No user action required.
• Scope (S): Unchanged (U) – The vulnerable component is the only one affected.
• Confidentiality (C): High (H) – Memory corruption can leak sensitive data.
• Integrity (I): High (H) – Attacker can modify memory.
• Availability (A): High (H) – Crash or denial of service is likely.

Estimated CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Estimated Base Score: 9.8 (Critical)

Threat Level: Critical. The vulnerability is remotely exploitable without authentication and can lead to full system compromise.

Deep Dive & Mechanics

The O-RAN RIC e2mgr (E2 Manager) is responsible for managing E2 sessions between the RIC and O-RAN nodes (e.g., gNBs, en-gNBs). The RicServiceUpdateHandler function processes service update messages from connected nodes. These messages contain arrays of service data (e.g., RAN function IDs, service types). The vulnerability arises because the handler does not validate the size of these arrays before copying data into fixed-size buffers.

Root Cause:
In the source code of e2mgr, the RicServiceUpdateHandler function likely uses a stack or heap buffer to store incoming service update data. The code reads the array length from the network message but fails to check if it exceeds the allocated buffer size. This allows an attacker to send a crafted message with a large array length, causing a buffer overflow.

Attack Flow:

1. Attacker sends a malicious E2 service update message to the e2mgr endpoint (typically TCP port 38000 or similar).
2. The message contains an array length field set to a value larger than the internal buffer.
3. The RicServiceUpdateHandler copies the array data into the undersized buffer without bounds checking.
4. The overflow corrupts adjacent memory, potentially overwriting function pointers, return addresses, or other critical data.
5. The attacker can then trigger code execution or cause a denial of service.

Impact:

• Remote Code Execution (RCE) with the privileges of the e2mgr process (often root).
• Denial of Service (DoS) by crashing the e2mgr service.
• Potential lateral movement within the O-RAN network.

Vulnerable vs. Patched Code

Since no official patch or source code diff is available, the following is a hypothetical example based on the vulnerability description.

Vulnerable Code (C pseudocode):

void RicServiceUpdateHandler(uint8_t *msg, size_t msg_len) {
    uint32_t num_services;
    ServiceUpdate services[32]; // Fixed-size buffer

    // Read number of services from message
    memcpy(&num_services, msg, sizeof(num_services));
    msg += sizeof(num_services);

    // VULNERABLE: No check if num_services > 32
    for (uint32_t i = 0; i < num_services; i++) {
        memcpy(&services[i], msg, sizeof(ServiceUpdate));
        msg += sizeof(ServiceUpdate);
    }
}

Patched Code (Hypothetical):

void RicServiceUpdateHandler(uint8_t *msg, size_t msg_len) {
    uint32_t num_services;
    ServiceUpdate services[32]; // Fixed-size buffer

    // Read number of services from message
    if (msg_len < sizeof(num_services)) {
        // Handle error
        return;
    }
    memcpy(&num_services, msg, sizeof(num_services));
    msg += sizeof(num_services);
    msg_len -= sizeof(num_services);

    // PATCH: Validate array size
    if (num_services > 32) {
        // Log error and reject
        return;
    }

    for (uint32_t i = 0; i < num_services; i++) {
        if (msg_len < sizeof(ServiceUpdate)) {
            // Handle error
            return;
        }
        memcpy(&services[i], msg, sizeof(ServiceUpdate));
        msg += sizeof(ServiceUpdate);
        msg_len -= sizeof(ServiceUpdate);
    }
}

Exploitation & Lab Setup

Red Team (Offensive)

Lab Environment:

• O-RAN RIC I-Release (vulnerable version) running in a Docker container.
• Attacker machine with Python3 and Scapy or a custom TCP client.
• Network connectivity between attacker and e2mgr port (default 38000).

Exploitation Steps:

1. Identify the e2mgr service IP and port (e.g., nmap -p 38000 <target>).
2. Craft a malicious E2 service update message with an oversized array length.
3. Send the message to trigger the buffer overflow.
4. Use a ROP chain or shellcode to gain code execution (requires knowledge of the target binary).

Example Python script (conceptual):

import socket

target_ip = "192.168.1.100"
target_port = 38000

# Craft malicious message
# Assume message format: [num_services (4 bytes)] [service_data (variable)]
num_services = 100  # Overflow value
payload = num_services.to_bytes(4, 'little')
payload += b"A" * (100 * 64)  # Overflow data

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((target_ip, target_port))
sock.send(payload)
sock.close()

Note: No public exploit code is available. The above is for educational purposes only.

Blue Team (Defensive)

Detection:

• Monitor network traffic for malformed E2 service update messages (e.g., unusually large array lengths).
• Use the Sigma and Suricata rules provided in the Detection Engineering section.
• Enable logging on the e2mgr service to capture crash dumps or error messages.

Mitigation:

• Apply vendor patches as soon as they are released.
• If patching is not possible, restrict network access to the e2mgr port using firewall rules.
• Deploy a Web Application Firewall (WAF) or intrusion prevention system (IPS) to filter malicious traffic.
• Run the e2mgr service with minimal privileges (e.g., non-root user) and enable ASLR/NX.

Indicators of Compromise (IOCs)

• Network IOCs:

  • TCP connections to port 38000 (or configured e2mgr port) with unusually large payloads.
  • E2 service update messages containing array length fields > 32 (or the expected buffer size).
  • Repeated connection attempts from the same IP address.

• Host IOCs:

  • Crash dumps or core files from the e2mgr process.
  • Log entries indicating "buffer overflow" or "segmentation fault" in e2mgr logs.
  • Unexpected child processes or shell spawns from the e2mgr PID.

• File IOCs:

  • Modified binaries or libraries in the e2mgr installation directory.
  • Suspicious files in /tmp or /var/tmp created by the e2mgr process.

Detection Engineering

YARA Rule

rule CVE_2024_34047_e2mgr_overflow {
    meta:
        description = "Detects potential exploitation of CVE-2024-34047 in O-RAN e2mgr"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-34047"
    strings:
        $s1 = "RicServiceUpdateHandler" ascii wide
        $s2 = "e2mgr" ascii wide
        $s3 = "service_update" ascii wide
    condition:
        all of them
}

Sigma Rule

title: CVE-2024-34047 - O-RAN e2mgr Buffer Overflow Attempt
id: 12345678-1234-1234-1234-123456789abc
status: experimental
description: Detects network traffic indicative of exploitation of CVE-2024-34047
author: Valters IT
logsource:
    category: network
    product: suricata
detection:
    selection:
        dest_port: 38000
        payload_length: "> 2048"  # Adjust based on normal traffic
    condition: selection
falsepositives:
    - Legitimate large service updates (rare)
level: high

Suricata Rule

alert tcp any any -> any 38000 (msg:"CVE-2024-34047 - O-RAN e2mgr Buffer Overflow Attempt"; flow:to_server; content:"|00 00 00 20|"; offset:0; depth:4; byte_test:4,>,32,0; classtype:attempted-admin; sid:1000001; rev:1;)

Note: The Suricata rule above checks for a 4-byte array length field at the start of the payload that exceeds 32. Adjust the offset and depth based on actual protocol analysis.

Remediation & Mitigation

1. Immediate Actions:

   • Isolate the e2mgr service from untrusted networks using firewall rules.
   • Monitor for any signs of exploitation using the provided detection rules.
   • If possible, disable the e2mgr service temporarily until a patch is available.

2. Vendor Patch:

   • Contact O-RAN Alliance or your vendor for an official patch.
   • Apply the patch as soon as it is released.

3. Long-term Mitigations:

   • Implement input validation and bounds checking in all network-facing components.
   • Use memory-safe languages (e.g., Rust) for critical components.
   • Conduct regular security audits and penetration testing of O-RAN deployments.

4. Workarounds:

   • If patching is not possible, deploy a reverse proxy or API gateway that validates message sizes before forwarding to e2mgr.
   • Enable stack canaries and other exploit mitigations in the e2mgr binary (requires recompilation).

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert