CVE-2025-22937

Executive Summary

CVE-2025-22937 is an unpatched privilege escalation vulnerability affecting the Adtran 411 ONT (Optical Network Terminal) running firmware version vL80.00.0011.M2. The vulnerability allows an attacker with initial access to escalate privileges via unspecified vectors, potentially gaining full administrative control over the device. No public proof-of-concept (PoC) or exploit code is available at this time, and the vendor has not released a patch. The CVSS score is currently unassigned, but the impact is considered high due to the critical role of ONT devices in network infrastructure.

This report provides a comprehensive technical analysis, detection strategies, and mitigation recommendations for security teams.

CVSS Breakdown & Threat Level

• CVSS Score: 0.0 (Unassigned)
• Attack Vector (AV): Unknown (likely Local or Adjacent Network)
• Attack Complexity (AC): Unknown
• Privileges Required (PR): Low (attacker needs initial access)
• User Interaction (UI): None
• Scope (S): Unchanged
• Confidentiality (C): High
• Integrity (I): High
• Availability (A): High

Threat Level: High. While no public exploit exists, the vulnerability affects a widely deployed network edge device. Successful exploitation could lead to full device compromise, enabling traffic interception, configuration changes, or lateral movement within the network.

Deep Dive & Mechanics

The Adtran 411 ONT is a fiber-optic network terminal used by ISPs to provide broadband services. The vulnerability resides in the device’s firmware vL80.00.0011.M2 and involves improper privilege management (CWE-269). An attacker with low-privileged access (e.g., via a compromised web interface or SSH) can exploit unspecified vectors—likely involving insecure API endpoints, SUID binaries, or misconfigured services—to escalate to root or administrator privileges.

Potential Attack Vectors:

• Insecure API Endpoints: The device may expose REST or SOAP APIs that allow privilege escalation without proper authorization.
• SUID Binary Exploitation: A setuid binary with a vulnerability (e.g., buffer overflow) could be used to gain elevated privileges.
• Misconfigured Services: Services running as root with weak permissions or exposed to unauthenticated users.

Impact:

• Full device takeover
• Modification of firmware or configuration
• Interception of network traffic
• Use as a pivot point for further attacks

Vulnerable vs. Patched Code

No patch is currently available. The vulnerable firmware version is vL80.00.0011.M2. Without a patched version, code comparison is not possible. However, the following hypothetical example illustrates the type of insecure code that could lead to privilege escalation:

Vulnerable Code (Hypothetical):

// Insecure SUID binary
int main() {
    setuid(0); // Set root privileges
    system("cp /tmp/exploit /etc/init.d/");
    return 0;
}

Patched Code (Hypothetical):

// Secure version with proper checks
int main() {
    if (geteuid() != 0) {
        fprintf(stderr, "Not running as root\n");
        exit(1);
    }
    // Perform secure operations
    return 0;
}

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Access to an Adtran 411 ONT with firmware vL80.00.0011.M2
• Low-privileged credentials (e.g., via default credentials or previous compromise)

Exploitation Steps:

1. Reconnaissance: Identify running services and SUID binaries.

   ssh user@<ONT_IP>
   find / -perm -4000 -type f 2>/dev/null
   

2. Exploit SUID Binary: If a vulnerable SUID binary is found, craft an exploit.

   # Example: Buffer overflow in a SUID binary
   ./vuln_binary $(python -c 'print "A"*100 + "\x90"*20 + "\x31\xc0\x50\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\x50\x53\x89\xe1\xb0\x0b\xcd\x80"')
   

3. Verify Privilege Escalation:

   id
   # Should show uid=0(root)
   

Note: No public exploit code exists. The above is a generic example.

Blue Team (Defense & Detection)

Detection Steps:

1. Monitor for SUID Binary Exploitation: Use auditd to log SUID binary executions.

   auditctl -a always,exit -F arch=b64 -S execve -F path=/bin/suid_binary -k suid_exploit
   

2. Network Monitoring: Look for unusual traffic from ONT devices to internal or external IPs.
3. Log Analysis: Check system logs for privilege escalation attempts.

   grep "su" /var/log/auth.log | grep "FAILED"
   

Mitigation:

• Restrict network access to ONT management interfaces.
• Disable unnecessary services and SUID binaries.
• Implement strict access controls and monitor for anomalies.

Indicators of Compromise (IOCs)

• File Hashes (SHA256):
  • firmware_vL80.00.0011.M2.bin: e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
• Network Indicators:
  • Unusual outbound connections from ONT to unknown IPs on ports 22, 80, 443
  • Traffic to known C2 domains (e.g., malicious-c2.example.com)
• System Indicators:
  • Unexpected SUID binaries in /tmp or /dev/shm
  • Modified /etc/passwd or /etc/shadow files
  • New user accounts with UID 0

Detection Engineering

YARA Rule

rule CVE_2025_22937_Adtran_ONT_PrivEsc {
    meta:
        description = "Detects potential privilege escalation on Adtran 411 ONT"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-22937"
    strings:
        $s1 = "vL80.00.0011.M2" ascii wide nocase
        $s2 = "setuid" ascii wide nocase
        $s3 = "root" ascii wide nocase
    condition:
        $s1 and ($s2 or $s3)
}

Sigma Rule

title: CVE-2025-22937 Privilege Escalation on Adtran 411 ONT
id: 12345678-1234-1234-1234-123456789012
status: experimental
description: Detects privilege escalation attempts on Adtran 411 ONT devices
author: Valters IT
date: 2025/04/10
logsource:
    product: linux
    service: auth
detection:
    selection:
        EventID: 1
        Image|endswith: '/suid_binary'
    condition: selection
falsepositives:
    - Legitimate administrative actions
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-22937 Adtran ONT Privilege Escalation"; flow:to_server,established; content:"|00 00 00 00|"; depth:4; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Isolate Affected Devices: Place Adtran 411 ONTs on a separate VLAN with strict firewall rules.
2. Disable Unnecessary Services: Turn off SSH, HTTP, and other management interfaces if not required.
3. Monitor Logs: Enable detailed logging and alerting for privilege escalation attempts.

Long-Term Fixes:

• Vendor Patch: Await an official firmware update from Adtran. Contact Adtran support for status.
• Firmware Hardening: If possible, replace the firmware with a custom hardened build.
• Network Segmentation: Implement zero-trust principles for all ONT devices.

Workarounds:

• Use network access control (NAC) to restrict device communication.
• Deploy an IDS/IPS to detect exploitation attempts.

Valters IT