CVE-2024-3109

Executive Summary

CVE-2024-3109 discloses a critical security flaw in the Motorola GuideMe application. The vulnerability combines a hard-coded AES encryption key with a lack of URI sanitization, enabling a local attacker with low privileges to read arbitrary files on the affected system. This poses a significant risk to data confidentiality, as sensitive files (e.g., configuration, credentials, user data) can be exfiltrated. The CVSS score of 6.3 reflects a medium severity, but the potential for privilege escalation or lateral movement elevates the threat. No public exploit code or patch is currently available, making detection and mitigation essential.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a proprietary Motorola application.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
• Base Score: 6.3 (Medium)
• Attack Vector: Local (AV:L) – requires local access to the device.
• Attack Complexity: Low (AC:L) – no special conditions needed.
• Privileges Required: Low (PR:L) – attacker needs a standard user account.
• User Interaction: None (UI:N) – no user action required.
• Scope: Unchanged (S:U) – vulnerability does not affect other components.
• Confidentiality Impact: High (C:H) – arbitrary file read.
• Integrity Impact: None (I:N)
• Availability Impact: None (A:N)

Threat Level: Medium. While the attack is local, the ability to read arbitrary files (including credentials and keys) can lead to further compromise.

Deep Dive & Mechanics

The vulnerability consists of two components:

1. Hard-coded AES Key: The Motorola GuideMe application contains a static AES encryption key embedded in its binary or configuration files. This key is used to encrypt/decrypt data, but because it is hard-coded, any attacker who extracts it can decrypt any data encrypted by the application.

2. Lack of URI Sanitation: The application fails to properly sanitize URIs when accessing local resources. An attacker can craft a malicious URI (e.g., file:///etc/passwd or file:///data/data/com.motorola.guideme/databases/sensitive.db) to read arbitrary files from the filesystem.

Attack Flow:

• The attacker gains local access (e.g., via a malicious app or ADB).
• The attacker identifies the hard-coded AES key (e.g., by reverse-engineering the APK).
• The attacker crafts a URI that points to a target file.
• The application processes the URI without validation, reads the file, and returns its contents (potentially encrypted with the hard-coded key, but the attacker can decrypt it).
• The attacker exfiltrates the data.

Vulnerable vs. Patched Code

Since no patch is available, we can only describe the vulnerable pattern.

Vulnerable Code (Conceptual):

// Hard-coded AES key
private static final String AES_KEY = "0123456789abcdef"; // Static key

// URI handling without sanitization
public String readFile(String uri) {
    // No validation of URI scheme or path
    File file = new File(new URI(uri));
    // Read and return file content
    return readFileContent(file);
}

Patched Code (Expected):

// Use a dynamically generated key stored securely (e.g., Android Keystore)
private KeyStore keyStore = KeyStore.getInstance("AndroidKeyStore");

// URI sanitization
public String readFile(String uri) {
    // Only allow specific paths or schemes
    if (!uri.startsWith("content://com.motorola.guideme/")) {
        throw new SecurityException("Invalid URI");
    }
    // Additional path traversal checks
    File file = new File(new URI(uri));
    if (!file.getCanonicalPath().startsWith("/data/data/com.motorola.guideme/")) {
        throw new SecurityException("Access denied");
    }
    return readFileContent(file);
}

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• Local access to a device running Motorola GuideMe (e.g., via ADB or a malicious app).
• Knowledge of the hard-coded AES key (extracted via reverse engineering).

Exploitation Steps:

1. Identify the AES key: Use strings or apktool to extract the key from the APK.

   strings GuideMe.apk | grep -i "aes"
   

2. Craft a malicious URI: Use the application's file-reading functionality.

   # Example using ADB to send an intent
   adb shell am start -n com.motorola.guideme/.FileReaderActivity -d "file:///data/data/com.motorola.guideme/databases/credentials.db"
   

3. Decrypt the output: If the file is encrypted with the hard-coded key, decrypt it.

   from Crypto.Cipher import AES
   key = b'0123456789abcdef'
   cipher = AES.new(key, AES.MODE_ECB)
   decrypted = cipher.decrypt(encrypted_data)
   

No public exploit code is available.

Blue Team (Defense)

Detection:

• Monitor for unusual file access patterns (e.g., reading /etc/passwd or /data/data/ files).
• Use file integrity monitoring (FIM) to detect unauthorized reads.
• Deploy endpoint detection and response (EDR) to flag processes accessing sensitive files.

Mitigation:

• Restrict local access to the device (e.g., disable ADB, use strong authentication).
• Apply principle of least privilege to the GuideMe application.
• If possible, use a sandbox or container to isolate the application.

Indicators of Compromise (IOCs)

• File Paths:
  • /data/data/com.motorola.guideme/databases/*.db
  • /data/data/com.motorola.guideme/shared_prefs/*.xml
  • /etc/passwd
  • /proc/self/environ
• Process Names:
  • com.motorola.guideme
• Network Connections: (if data is exfiltrated)
  • Outbound connections to unknown IPs on port 80/443.
• Registry/Config Changes: (if applicable)
  • Modified application preferences.

Detection Engineering

YARA Rule

rule CVE_2024_3109_Motorola_GuideMe_Hardcoded_AES {
    meta:
        description = "Detects hard-coded AES key in Motorola GuideMe APK"
        author = "Valters IT"
        date = "2025-04-10"
        reference = "CVE-2024-3109"
    strings:
        $aes_key = /AES_KEY\s*=\s*"[0-9a-fA-F]{16}"/ nocase
        $aes_key2 = /private static final String AES_KEY = "[0-9a-fA-F]{16}"/ nocase
    condition:
        any of them
}

Sigma Rule

title: CVE-2024-3109 - Motorola GuideMe Arbitrary File Read
id: 8f4b3c2a-1d5e-4f7b-9a0c-3e6d8f2b1a4c
status: experimental
description: Detects attempts to read arbitrary files via Motorola GuideMe application
author: Valters IT
date: 2025-04-10
logsource:
    category: process_creation
    product: windows
detection:
    selection:
        Image|endswith: 'GuideMe.exe'
        CommandLine|contains: 'file://'
    condition: selection
falsepositives:
    - Legitimate file access by the application
level: high

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (
    msg:"CVE-2024-3109 - Motorola GuideMe Data Exfiltration";
    flow:to_server,established;
    content:"GET"; http_method;
    content:"/data/"; http_uri;
    pcre:"/file:\/\/\//";
    sid:1000001;
    rev:1;
)

Remediation & Mitigation

Immediate Actions:

1. Isolate the application: If possible, uninstall or disable Motorola GuideMe until a patch is available.
2. Restrict local access: Disable ADB, USB debugging, and other local access vectors.
3. Monitor logs: Enable detailed logging for file access and process execution.

Long-term Fix:

• Vendor: Motorola must release a patch that:
  • Removes hard-coded AES keys and uses a secure key management system (e.g., Android Keystore).
  • Implements strict URI validation (allowlist of allowed paths/schemes).
  • Adds runtime permission checks for file access.

Workarounds:

• Use a mobile device management (MDM) solution to enforce policies that block the application.
• Deploy a custom SELinux policy to restrict the application's file access.

Valters IT
DevSecOps & Cyber Threat Intelligence Expert