CVE-2023-41826

Executive Summary

CVE-2023-41826 is a PendingIntent hijacking vulnerability discovered in the Motorola Device Help (Genie) application. This flaw allows a local attacker with minimal privileges to intercept and modify PendingIntents, enabling unauthorized access to files or interaction with non-exported software components. The vulnerability has a CVSS score of 5.1 (Medium), indicating a moderate risk primarily due to the requirement of local access. No public proof-of-concept (PoC) or exploit code has been released, and the patch status remains unknown. The attack surface is limited to devices with the vulnerable Genie app installed, typically Motorola Android devices.

Supply Chain & Package Security

This vulnerability is not related to NPM, PyPI, Go, or Ruby packages. It is a pre-installed Android application vulnerability within the Motorola supply chain.

CVSS Breakdown & Threat Level

• CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
• Base Score: 5.1 (Medium)
• Attack Vector (AV): Local (L) – The attacker must have physical or ADB access to the device.
• Attack Complexity (AC): Low (L) – No special conditions required.
• Privileges Required (PR): Low (L) – The attacker needs a low-privileged app or user account.
• User Interaction (UI): None (N) – No user action needed beyond initial access.
• Scope (S): Unchanged (U) – The vulnerable component and the attacker’s component are in the same security authority.
• Confidentiality (C): Low (L) – Limited file access possible.
• Integrity (I): Low (L) – Limited ability to modify data.
• Availability (A): Low (L) – Limited impact on service availability.

Threat Level: Medium. Exploitation requires local access, reducing the attack surface but still posing a risk in multi-user or enterprise environments.

Deep Dive & Mechanics

The vulnerability resides in the PendingIntent mechanism used by the Motorola Device Help (Genie) application. PendingIntents are tokens that allow other applications to perform predefined actions on behalf of the granting app. In this case, the Genie app creates PendingIntents that are implicit or mutable, allowing a malicious local application to intercept and modify them.

Technical Flow:

1. The Genie app creates a PendingIntent with FLAG_IMMUTABLE not set (or set incorrectly), making it mutable.
2. A malicious app on the same device can use Intent matching to intercept this PendingIntent.
3. The attacker modifies the Intent’s extras or data URI to point to sensitive files or non-exported components.
4. When the Genie app triggers the PendingIntent, the modified Intent executes, granting the attacker access.

Impact:

• File Access: The attacker can read files from the Genie app’s private directory or other accessible locations.
• Component Interaction: The attacker can invoke non-exported activities, services, or broadcast receivers within the Genie app, potentially leading to privilege escalation.

Vulnerable vs. Patched Code

Since no patch details are available, we provide a conceptual comparison.

Vulnerable Code (Java/Kotlin):

// Vulnerable: Mutable PendingIntent without FLAG_IMMUTABLE
Intent intent = new Intent(this, TargetActivity.class);
intent.putExtra("file_path", "/data/data/com.motorola.genie/files/sensitive.txt");
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, 0);

Patched Code (Java/Kotlin):

// Patched: Immutable PendingIntent with FLAG_IMMUTABLE
Intent intent = new Intent(this, TargetActivity.class);
intent.putExtra("file_path", "/data/data/com.motorola.genie/files/sensitive.txt");
PendingIntent pendingIntent = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_IMMUTABLE);

The key difference is the addition of PendingIntent.FLAG_IMMUTABLE (or PendingIntent.FLAG_UPDATE_CURRENT with proper validation). This prevents the Intent from being modified by other apps.

Exploitation & Lab Setup

Red Team (Exploitation)

Prerequisites:

• A rooted or ADB-enabled Motorola device with the Genie app installed.
• A malicious Android app installed on the same device.

Exploitation Steps:

1. Identify the vulnerable PendingIntent: Use dumpsys package or logcat to find PendingIntents created by the Genie app.
2. Create a malicious app that registers an Intent filter matching the Genie app’s PendingIntent.
3. Intercept and modify the Intent: Use Intent matching to replace the data URI or extras.
4. Trigger the PendingIntent: The Genie app will execute the modified Intent, granting access.

Example Malicious App Code (Kotlin):

// Malicious app intercepting PendingIntent
class MaliciousReceiver : BroadcastReceiver() {
    override fun onReceive(context: Context, intent: Intent) {
        // Modify the Intent to access sensitive data
        intent.data = Uri.parse("file:///data/data/com.motorola.genie/files/sensitive.txt")
        // Execute the modified Intent
        context.startActivity(intent)
    }
}

Blue Team (Defense)

Detection Steps:

1. Monitor for unusual PendingIntent usage: Use dumpsys activity intents to list active PendingIntents.
2. Check for mutable PendingIntents: Look for apps creating PendingIntents without FLAG_IMMUTABLE.
3. Audit app permissions: Ensure no untrusted apps have BIND_ACCESSIBILITY_SERVICE or SYSTEM_ALERT_WINDOW permissions that could facilitate hijacking.

Mitigation:

• Apply the vendor patch when available.
• Restrict installation of apps from unknown sources.
• Use Android Enterprise or MDM solutions to enforce security policies.

Indicators of Compromise (IOCs)

• File Paths:
  • /data/data/com.motorola.genie/files/*
  • /data/data/com.motorola.genie/databases/*
• Process Names:
  • com.motorola.genie
• Log Entries:
  • PendingIntent hijacking detected
  • Intent modified by unknown app
• Network Traffic: None expected (local vulnerability).

Detection Engineering

YARA Rule

rule CVE_2023_41826_PendingIntent_Hijacking {
    meta:
        description = "Detects mutable PendingIntent creation in Motorola Genie app"
        author = "Valters IT"
        date = "2025-04-10"
        cve = "CVE-2023-41826"
    strings:
        $s1 = "PendingIntent.getActivity" ascii wide nocase
        $s2 = "FLAG_IMMUTABLE" ascii wide nocase
        $s3 = "com.motorola.genie" ascii wide nocase
    condition:
        $s1 and not $s2 and $s3
}

Sigma Rule

title: CVE-2023-41826 PendingIntent Hijacking in Motorola Genie
id: 8a4b3c2d-1e5f-4a7b-9c8d-0e1f2a3b4c5d
status: experimental
description: Detects mutable PendingIntent creation in Motorola Device Help app
author: Valters IT
date: 2025-04-10
logsource:
    product: android
    service: logcat
detection:
    selection:
        - 'PendingIntent.getActivity' 
        - 'com.motorola.genie'
    condition: selection
falsepositives:
    - Legitimate use of mutable PendingIntents in other apps
level: medium

Suricata Rule

alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"CVE-2023-41826 PendingIntent Hijacking Attempt"; flow:to_server; content:"com.motorola.genie"; nocase; content:"PendingIntent"; nocase; classtype:attempted-user; sid:1000001; rev:1;)

Remediation & Mitigation

Immediate Actions:

1. Disable or uninstall the Motorola Device Help (Genie) app if not required.
2. Restrict app installation to trusted sources only.
3. Monitor for suspicious app behavior using mobile threat defense (MTD) solutions.

Long-term Fix:

• Apply the vendor patch when released. The fix involves setting FLAG_IMMUTABLE on all PendingIntents.
• For developers: Always use PendingIntent.FLAG_IMMUTABLE (or FLAG_MUTABLE only when necessary with proper validation).

Workarounds:

• Use Android’s AppOps to revoke the Genie app’s permissions.
• Implement Intent validation in custom apps to reject modified Intents.

Valters IT