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Introduction
TrickMo, a notorious Android banking trojan, has re-emerged with a completely redesigned backend architecture, shifting focus from flashy user‑interface changes to stealthy, resilient device takeover (DTO) capabilities. This latest variant aggressively targets banking, fintech, wallet, and — critically — authenticator applications, undermining multi‑factor authentication (MFA) by stealing one‑time passwords (OTPs) and session tokens in real time. By coercing victims into granting Accessibility permissions, attackers gain full remote control, including screen viewing and interaction, effectively bypassing traditional security layers.
Learning Objectives
- Identify behavioral indicators of TrickMo infection, including Accessibility service abuse and unusual overlay requests.
- Apply both manual and automated detection techniques using Android Debug Bridge (ADB) and network traffic analysis.
- Implement hardening measures on Android devices and develop incident response steps to remove the malware and recover compromised accounts.
You Should Know
1. Understanding TrickMo’s Core Capabilities and Stealth Mechanisms
The new TrickMo variant does not introduce novel user‑facing tricks; instead, it refines how it operates under the hood. It retains full device takeover (DTO) — remote screen viewing, touch injection, and keylogging — but adds enhanced persistence, anti‑analysis checks, and modular command execution. The malware aggressively pushes fake system update or security warning overlays to trick users into enabling Accessibility permissions, which then grant the attacker unrestricted control.
Step‑by‑step guide to understanding Accessibility abuse:
- On a test device (never on a production phone), enable Developer Options and USB debugging.
- Connect the device to a Linux/macOS/Windows machine with ADB installed.
- List all packages that hold Accessibility permissions using ADB:
– Linux / macOS / Windows (ADB command):
`adb shell settings get secure enabled_accessibility_services`
- To see which accessibility services are active:
`adb shell dumpsys accessibility | grep -A 5 “Services:”`
4. If unknown or suspicious package names appear (e.g., random strings, fake system names), that’s a red flag for malware like TrickMo.
- Detecting TrickMo Infection on Android (Using ADB and Package Inspection)
Because TrickMo hides under generic or system‑mimicking names, you need to scan for runtime indicators. The malware may request permissions like SYSTEM_ALERT_WINDOW, BIND_ACCESSIBILITY_SERVICE, and `REQUEST_INSTALL_PACKAGES` without proper justification.
Step‑by‑step detection with ADB (Linux/Windows compatible):
1. List all installed third-party packages:
`adb shell pm list packages -3`
(This shows user‑installed apps only.)
- Look for recently installed apps by checking installation timestamps (requires root on some devices, but can use):
`adb shell dumpsys package packages | grep -A 2 “install”`
3. Check for dangerous permission grants:
`adb shell dumpsys package
Focus on `android.permission.BIND_ACCESSIBILITY_SERVICE` and `SYSTEM_ALERT_WINDOW`.
- On Windows (PowerShell), you can run similar commands using the ADB executable. Example:
`adb shell “pm list packages -3” | Out-String`
3. Network Traffic Analysis for TrickMo C2 Communication
TrickMo uses encrypted (often HTTPS) communication to its command‑and‑control (C2) servers, but it may also fall back to plain HTTP or use unusual ports. Analyzing network traffic from an infected emulator or sandbox can reveal domains, IPs, and data exfiltration patterns.
Linux setup for traffic capture:
- Route the Android device/emulator traffic through a proxy (mitmproxy or Burp Suite):
– On Linux, start mitmproxy: `mitmweb –set block_global=false`
– Set the device’s proxy to your Linux machine’s IP, port 8080.
- Alternatively, use tcpdump on the host if the device is on the same network:
`sudo tcpdump -i eth0 -w trickmo_traffic.pcap host `
3. Analyze with Wireshark (also on Windows):
- Filter for TLS handshakes: `tls.handshake.type == 1`
- Look for suspicious SNI (Server Name Indication) domains that are not legitimate banking services.
- Windows equivalent – Use Wireshark with `netsh` to capture traffic from the Android device’s IP if connected via a Wi‑Fi hotspot.
4. Reverse Engineering the TrickMo APK (Static Analysis)
Reverse engineering the malware helps extract IOCs (hashes, C2 URLs, encryption keys). Always perform this in an isolated VM.
Step‑by‑step for Linux (commands also work on Windows via WSL or Cygwin):
- Obtain the APK from a sandbox sample (e.g., VirusShare, Malshare).
2. Decompile with apktool:
`apktool d malicious.apk -o trickmo_decompiled`
- Convert DEX to Java using jadx (graphical or CLI):
`jadx -d trickmo_java_source malicious.apk`
4. Search for strings indicative of C2 communication:
`grep -r -E “https?://|ws://|socket” trickmo_java_source/`
- Look for Accessibility service implementation – typically a class extending
AccessibilityService. Use:
`find . -name “.java” -exec grep -l “AccessibilityService” {} \;` - Extract the AndroidManifest.xml (converted by apktool) to verify requested permissions:
`cat trickmo_decompiled/AndroidManifest.xml | grep -E “uses-permission|accessibility”`
5. Hardening Android Devices Against Banking Malware
Prevention is far easier than cleanup. Follow these steps to block TrickMo before it gains a foothold.
Step‑by‑step hardening guide for end users and enterprise devices:
- Disable installation from unknown sources (Google Play Store only).
On Android 8+: Settings → Security → Install unknown apps → turn off for all browsers and messaging apps. -
Enable Google Play Protect (real‑time scanning). Verify it’s active:
`adb shell cmd package bg-dexopt-job` (checks Play Protect status; alternatively, view in device settings). -
Use a dedicated authenticator app with hardware backup (e.g., Google Authenticator’s cloud backup off, or a hardware key). TrickMo cannot steal hardware keys.
-
Apply a mobile threat defense (MTD) solution for enterprise‑managed devices. Open‑source options:
– Install Hypatia (real‑time signature scanner) from F‑Droid.
– Use TrackerControl to block suspicious network traffic.
- Biometric confirmation for banking apps – inside banking app settings, enforce fingerprint/passcode for every transaction, not just login.
-
Linux/Windows command to audit a backup of installed apps (offline analysis):
`adb shell pm list packages -f > app_list.txt`
Then manually review against known malware package names.
- Incident Response: Removing TrickMo and Recovering Compromised Accounts
If an infection is suspected, act immediately. TrickMo may have disabled Google Play Protect or admin lockouts.
Emergency response steps:
- Boot into Safe Mode (press and hold power button, then tap and hold “Power off” → “Reboot to Safe Mode”). This disables third‑party apps.
-
Uninstall the malicious app via ADB (even if device admin is locked):
`adb uninstall `
If uninstall fails, try:
`adb shell pm uninstall -k –user 0 `
- Revoke Accessibility permissions for all suspicious apps using ADB:
`adb shell settings put secure enabled_accessibility_services “”`
- Factory reset (last resort, but guaranteed to remove persistence). Backup only essential data (no app backups, only photos/docs).
`adb reboot recovery` → choose “Wipe data/factory reset”.
-
After reset, change all passwords for banking, email, and authenticator apps from a clean machine. Enable new MFA secrets.
-
Notify your bank so they can flag potential fraud and roll back sessions.
-
API Security & Cloud Hardening for Financial Apps (Mitigation at the Server Side)
Banking and wallet applications can reduce damage even if TrickMo compromises a device. Implement these API‑level controls.
Step‑by‑step for developers and cloud architects:
- Enforce certificate pinning in the mobile app’s network layer (e.g., OkHttp’s
CertificatePinner) to block man‑in‑the‑middle attacks. -
Implement device attestation using Google Play Integrity API. Reject API calls from devices that fail basic integrity or have unknown sources enabled.
-
Use behavioral rate limiting on login and token refresh endpoints. If a single user has multiple IPs or unusual device fingerprints in a short window, trigger step‑up authentication.
-
Add a server side check for `X-Requested-With` header (not fully reliable but an extra layer) to detect non‑browser, automated requests.
-
Windows/Linux command to test API endpoint for missing pinning (using curl with custom CA or –insecure flag to simulate device attack):
`curl -k –proxy http://malicious-proxy:8080 https://yourbank.com/api/balance` -
Leverage Web Application Firewall (WAF) rules to detect geolocation anomalies and known TrickMo C2 patterns (e.g., suspicious User‑Agent strings like `Dalvik/2.1.0` + unexpected `Accept` headers).
What Undercode Say
- Accessibility permissions are the new root. Any app that aggressively pushes for this permission without a clear, user‑initiated purpose should be treated as critical malware.
- MFA is not invincible. TrickMo’s targeting of authenticator apps proves that token‑based 2FA on the same device as the malware is vulnerable. Hardware keys or isolated second devices remain the gold standard.
- Proactive detection beats reactive cleanup. Regular ADB audits, network monitoring, and enabling Google Play Protect can stop TrickMo before it requests Accessibility access.
- Server‑side API hardening is often overlooked. Even if the device is compromised, certificate pinning and device attestation can prevent token theft and session hijacking.
- Reverse engineering is accessible to defenders. Open‑source tools like `jadx` and `apktool` allow analysts to extract C2 URLs and behaviors without a commercial license – a skill every blue team should include in training.
Prediction
As Android banking malware like TrickMo continues to evolve backend architectures for stealth and persistence, the next generation will likely incorporate AI‑driven evasion — dynamically changing C2 domains, generating realistic fake overlays using on‑device LLMs, and automatically disabling security software. Simultaneously, attackers will shift focus from stealing credentials to abusing authenticated sessions via WebSockets, making traditional token revocation less effective. The financial industry will be forced to adopt continuous behavioral authentication (e.g., typing cadence, swipe patterns) and move critical actions to trusted execution environments (TEE) that even Accessibility malware cannot reach. Expect regulatory pressure to mandate hardware‑based MFA for all banking apps within 24–36 months.
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Reported By: Mayura Kathiresh – Hackers Feeds
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